Botanical in the management of Plant diseases - CiteSeerX

CCEENNTTRREE OOFF AADDVVAANNCCEEDD SSTTUUDDIIEESS

IINN

PPLLAANNTT PPAATTHHOOLLOOGGYY

(Indian Council of Agricultural Research, New Delhi)

Proceedings of the 21st

Training

on

““RReecceenntt AAddvvaanncceess iinn PPllaanntt DDiisseeaassee MMaannaaggeemmeenntt””

DDeecceemmbbeerr 1133,, 22000088 ttoo JJaannuuaarryy 0022,, 22000099

DDDrrr... JJJ... KKKuuummmaaarrr,,, DDDiiirrreeeccctttooorrr CCCAAASSS

DDDrrr... SSS...CCC... SSSaaaxxxeeennnaaa,,, CCCooouuurrrssseee CCCoooooorrrdddiiinnnaaatttooorrr

GG..BB.. PPAANNTT UUNNIIVVEERRSSIITTYY OOFF AAGGRRIICCUULLTTUURREE AANNDD TTEECCHHNNOOLLOOGGYY

PANTNAGAR- 263 145 (UTTARAKHAND)

PREFACE

Increase in agricultural production is the key to all-over economic growth of the country.

In view of increasing world population and escalating overall food requirements rapid growth of

agriculture is essential for ensuring food security and alleviating poverty. Growing demand must

be met primarily by increasing production on land already under cultivation and by reducing

losses due to diseases and pests. The main constrains for plant growth and, at the same time, one of

the culprits are plant pathogens, such as fungi, bacteria, viruses and nematodes etc. are serious

constraints to crop productivity. In worst-case scenario, these pathogens can be disastrous and

even life threatening. Disease management needs to be understood in light of general evolution of

these organisms. Estimation of losses attributed to seed and soil borne inoculum, establishing

predictive relationships between host & parasite and disease incidence, developing reliable,

effective, cheap and rapid control methods, dialogue with the private sector on development of

modules and comparing data on advantages of plant health are the current issues. Besides,

increasing crop productivity, plant health issues are exremely important in international trade and

conservation and utilization of plant genetic resources, which is vital for global food security.

To address this emerging challenge, the 21st CAS training on ‘Recent Advances in Plant

Disease Management’ was visualized. Excellent response was received from all over India for

participation in this training. Twenty participants representing 10 states actively participated in the

programme for 21 days. They were exposed to the recent advances in plant disease management

through lectures, practical and field visits on various aspects of pests and disease management.

Scientific areas covered included series of lectures covering various aspects of technological

innovations with respect to disease management, storage pests and GMOs, protection, etc.

We are grateful to the ICAR for sponsoring this 21st CAS training programme. We are

highly grateful to Prof. B.S. Bisht, Vice-Chancellor for his constant support, guidance and

encouragement in making the training a great success. We put on record the help and guidance

received from Dr. J.P. Tiwari, Dean Agriculture, Dr. D.P. Singh, Director Research and Dr. K. P.

Singh, Director Extension Education in the successful conduct of training programme. We

sincerely acknowledge the services of our guest speakers Dr. (Mrs.) Abha Agnihotri, TERI, New

Delhi; Dr. Ram Kishun, CISH, Lucknow; Dr. R.J. Rabindra, Director PDBC, Bangalore; Dr. K.N.

Pathak and Dr. R.C. Rai, RAU, Bihar; Dr. H.N. Gour and Dr. A.U. Siddique, MPUA&T, Udaipur;

Dr. B.P. Singh, Modipurum, Meerut; Dr. Akhtar Haseeb, AMU, Aligarh; Dr. T.S. Thind, PAU,

Ludhiana; Dr. Y.P. Sharma, Flowerdale, Shimla; Dr. R.K. Khetrapal, NBPGR, New Delhi; Dr.

Yogesh Negi, Dehradun; Dr. Y.P. Singh, FRI, Dehradun; Dr. R.D. Kapoor, Monsanto India Ltd.,

New Delhi and Dr. S.P.S. Beniwal, ex-Regional Coordinator, ICARDA. We would be failing in our

duty if we do not acknowledge the help and logistic support received from Dr. M.C. Nautiyal,

Dean, Hill Campus, Ranichauri and his team of scientists for delivering lectures during exposure

visit of participants. Several scientists from various departments such as Soils Science,

Entomology, Genetics and Plant Breeding, Agric. Communication, Agrometeorology Biological

Science, Microbiology, Molecular Biology & Genetic Engineering, Vet. Anatomy and the

University library in addition to Plant Pathology rendered all possible help and delivered scientific

lectures and designed practical exposure to the participants. We acknowledge their contributions

with utmost gratitude and sincerity.

Pantnagar

Jan. 02, 2009

S.C. Saxena

Course Coordinator

J. Kumar

Director, CAS

CONTENTS

Sl. No. Title Speaker Page

Welcome Address Dr. J. Kumar i-iii

Inaugural Address Prof. B.S. Bisht i-iii

1. Department of Plant Pathology Dr. J. Kumar 1-22

2. Addressing Nutrient Deficiencies and Toxicities in

Crops

Dr. P.C. Srivastava 23-24

3. GIS Application in Precision Farming and Plant

Disease Management

Dr. A.K. Agnihotri

25-31

4. Soil Health and Plant Disease Management Dr. B. Mishra 32-35

5. Biotechnological Approaches for Incorporation of

Fungal Disease Resistance

Dr. Abha Agnihotri 36-38

6. Recent Advances in Integrated Management of

Vegetable Diseases

Dr. S.N.

Vishwakama

39-41

7. Managing disease through host resistance Dr. D. Roy 42-43

8. Recent Advances in Management of Wilt and Root

Rot Complexes of Chickpea (Cicer Arietinum L.)

Dr. H.S. Tripathi 44-46

9. Micro-Meteorology in Relation to Plant Disease

Development

Dr. H.S. Kushwaha 47-53

10. Visit to Meteorological Observatory and Automatic

Weather Station in Cropped Field at CRC

Dr. H.S. Kushwaha 54-59

11. Technology Transfer: Experiences of Uttarakhand Dr. K. P. Singh 60-62

12. Recent Advances in Management of Bacterial

Diseases of Subtropical Fruits

Dr. Ram Kishun 63-67

13. Electron Microscopy: A Tool for study of

Ultrastructural Pathology

Dr. Balwinder Singh

Dhote

68-76

14. Advances in Eco-Friendly Approaches in IPM Dr. Ruchira Tiwari 77-84

15. Problems and Progress of Research on Alternaria

Blight Resistance in Rapeseed-Mustard

Dr. R.P. Awasthi

85-86

16. Advancement in Seed Health Testing Techniques

for Better Disease Management

Dr. (Mrs.) Karuna

Vishunavat

87-91

17. A Brief Tutorial on Use of Bioinformatics Tools for

Plant Pathologist

Dr. S. Marla 92-98

18. Plant Nematological Contributions to

Phytopathology

Dr. K. N. Pathak 99-103

19. Status of Karnal Bunt of Wheat and its Management Dr. R.C. Rai 104-119

i

20. Entomopathogenic Nematodes and their Role in

Biological Control of Insect Pests

Dr. A.U. Siddiqui 120-131

21. Recent Advances in the Management of Maize

Diseases

Dr. S.C. Saxena

132-133

22. Phosphate Solubilizing Bacteria and their Role in

Crop Growth and Disease Management

Dr. (Mrs.) Reeta

Goel

134-141

23. Plant Parasitic Nematodes– A Major Constraint to

Agricultural Productivity and their Management

Dr. Akhtar Haseeb 142-147

24. New Generation Fungicides Dr. T.S. Thind 148-151

25. Advances in the Management of Sheath Blight

Disease of Rice

Dr. A.P. Sinha 152-156

26. Integrated Management of Maize Diseases with

Special Reference to Banded Leaf and Sheath Blight

Dr. S.C. Saxena

157-159

27. Role and limitations of Botanicals in the

Management of Plant Diseases

Dr. A.P. Sinha 160-165

28. Arbuscular Mycorrhiza: A Potential Bioagent for

Managing Plant Disease

Dr. A. K. Sharma

166-170

29. Wheat Stem Rust Ug 99- A Threat to Food Security Dr. Y.P. Sharma 171-173

30. Management of Transboundary Movement of Pests Dr. R.K. Khetarpal 174-182

31. Pathogen Population Considerations in Developing

Durable Disease Resistance: A Case Study of Rice

Blast Pathosystem

Dr. J. Kumar

183-187

32. Role of PGPR in Plant Disease Management Dr. Yogesh K. Negi 188-192

33. Recent Advancement in the Management of Apple Scab Dr. K.P. Singh 193-198

34. Soil Solarization: An Effective and Ecofriendly

Disease Management Strategy

Dr. Y. Singh

199-203

35. Modeling Plant Disease Epidemics for Crop

Protection

Dr. V.S. Pundhir

204-207

36. Epidemiological Approaches to Disease

Management through Seed Technology

Dr. (Mrs.) Karuna

Vishunavat

208-214

37. Climate Change in the Hilly Regions Dr. N.S. Murty 215-222

Chairman’s Address Prof. B.S. Bisht i-ii

Annexure- I (Committee members) --- i-ii

Annexure- II (List of Participants) --- i-iii

Annexure- III (List of Speakers) --- i-ii

Annexure- IV (List of Training Course Schedule) --- i-iv

ii

WELCOME ADDRESS by

Dr. J. Kumar Director CAS

Prof. & Head, Plant Pathology, College of Agriculture

G.B. Pant University of Agriculture & Technology, Pantnagar- 263 145

on

December 13, 2008

Good morning and welcome to the

Inaugural Session of the 21st CAS training on

“Recent Advances in Plant Disease

Management”.

Hon’ble, Vice-Chancellor Dr. B.S. Bisht;

Dean Agriculture Dr. J.P. Tiwari; Dr. D.P. Singh

Director Experiment Station, Dr. K.P. Singh,

Director Extension, Dr. S.C. Saxena, Course

Coordinator of the present training, Deans and

Directors, Jt. Directors, Officers, Heads of

Departments, Senior faculty members,

Colleagues, Staff members, the trainees from

different universities, Students, Press & Media,

Ladies & Gentle men.

At the outset, on behalf of faculty of Plant

Pathology and on my own behalf, it is a pleasure

in welcoming the Chief Guest of the function,

honorable Dr. B.S. Bisht, Vice-Chancellor of this

University who is known for his boundless

energy, passion, integrity and commitment. Dr.

Bisht, an alumni of this University, has had a long

distinguished professional career in various

capacities in the country before joining ICAR

where he was responsible for designing,

implementing and monitoring human resource

development programmes towards academic

excellence and R&D. Dr. Bisht is a big support

and source of inspiration for the pursuance of

research and academics in this Great University

as well. You have consented to grace this

occasion despite your very hectic schedule of

work, we are all very grateful to you, Sir.

It is a pleasure in welcoming Dr. J. P.

Tiwari the Dean, College of Agriculture. Dr. Tiwari

is vastly experienced and has held several

important positions such as Head, Department of

Horticulture, Registrar, and Dean, P.G.S. Dr.

Tiwari has held college of agriculture in high

esteem. We all members of Plant Pathology

faculty welcome you sir.

I am also pleased to welcome Dr. D. P.

Singh, Director Experiment Station and renowned

Plant Breeder in the country, who has developed

a number of varieties of various pulses that are

widely grown in the country. Dr. Singh has also

held various other important positions such as

Dean PGS and Head of the Department of

Genetics & Plant Breeding . I like to welcome you

to this function, sir.

It is again a pleasure in welcoming Dr.

K.P. Singh, the Director Extension, who is

essentially a Plant Pathologist and has

tremendous experience in administration,

research and extension. He is a tremendous

support in establishing extension linkages and

registering our existence at the end of farming

community in the State.

I would also like to welcome Dr. S.C.

Saxena, one of the senior most persons in the

College and a guest faculty in the Department of

Plant Pathology. Dr. Saxena is the First

i

Generation Staff in the Department as well as the

College and is an appropriate interface to the

newer generations coming to the Department.

I welcome our esteemed Registrar,

Deans and Directors, Jt. Directors, Officers who

are present here in the hall. They have spared

their valuable time to grace this occasion.

The Heads and faculty members of

various departments have also responded to our

request and are present in the hall. I welcome all

of you to the function.

The participants of the training from

different universities have traveled a long distance

to reach Pantnagar. While at Pantnagar you

may miss the comforts and attractions of big cities

but the warmth of academics that exist at this

place and a very exhaustive work that awaits you

should keep you engrossed and compensate for

any logistic inadequacies. I welcome you all and

assure you a comfortable stay within our means.

In the last, but not the least, I welcome all

our students and staff, press and media and

others who are present in the hall and have made

the arrangements for this inaugural session.

Ladies and gentlemen, the Department of

Plant Pathology was created and accredited by

ICAR in 1961 and ever since the Department has

had a strong commitment to, and history of,

sound education, research and extension in Plant

Pathology. Dr. Y.L.Nene was the first Head of the

Department. Under his capable leadership, the

department expanded to include many dedicated

faculty members whose programmes made the

Department the recognized leader in the country.

The next generation of faculty members like the

first responded to the changing needs presented

by the modern agriculture. At present the

Department includes 14 professors, one senior

professor as guest faculty, one honourary

professor from INRA, France, four Associate

Professors and two Assistant Professors with 13

technical and 10 supporting staffs. The entire

staff upholds the Department’s commitment to

education, basic and applied research and

extension

The Department has a well-knit under

graduate (U.G.) and post graduate (P.G.)

programme with updated and modern course

curricula. It offers six U.G. and 20 P.G. courses.

A broad range of carefully designed courses

complimented by lectures in other Departments

appropriately address the academic needs of the

students. The great diversity of areas of expertise

and interests present in the Department leads to

diversity in thesis titles. So far almost 300 M.Sc.

and 155 Ph.D. students have earned degrees

from the Department.

The Department is actively engaged in

the research work on both fundamental and

applied aspects in the domains of ecology of soil

borne plant pathogens, epidemiology and

forecasting, biological control and IPM including

small farms technologies, molecular diagnostics,

pathogen population biology, disease resistance,

seed pathology, fungicides, nematology,

phytovirology, phytobacteriology and biology &

technology of mushroom production.

The distinguished faculty of the

Department has brought in a number of national

and international research grants besides a series

of AICRPS. For a number of AICRPs such as

those of Rice, Wheat, Oilseeds, Potato, Seeds

and Small millets the faculty members of the

Department render services as the Project

Coordinators also.

Over the years, the trained and

accomplished faculty members as well as

students in addressing current issues in Plant

Pathology have won over 40 national and

international awards. Individual staff members

with in the department have long been recognized

for their leadership role in the science of Plant

ii

Pathology. By way of their contributions many

faculty members of the Department have earned

International positions. Also a number of faculty

members have served as president, vice

presidents, and zonal president of several

professional societies

The Department has a unique distinction

of producing 35 books published by not only

Indian but also reputed international publishers.

This is besides a series of technical bulletins, lab

manuals, compendia and extension literature that

have also been prepared.

The Department, besides other fields,

has a strong set up in IPM and biocontrol.

Recently Government of India has declared the

Biocontrol Lab as `Central Insecticide Lab’ for

biopesticides. Similarly the Department also holds

big strength in mushroom research and trainings.

In view of quality of teaching, research

and extension work being carried out by the

department, ICAR upgraded the department to

the status of CAS in Plant Pathology in the year

1995 with the major mandate to train scientific

faculty from all over the country in important and

innovative areas of Plant Pathology. So far 20

trainings have been conducted and 416 scientists

from 24 states have participated.

The topic of the present training under

CAS is ‘Recent Advances in Plant Disease

Management’. As you know, plant diseases,

need not be epidemics, are of paramount

importance to human well being. They can make

the difference between a comfortable life and life

haunted by hunger, misery or even death from

starvation. A most devastating event that vividly

illustrates the consequences of a plant disease

was the Irish Potato famine of the 1840s, which

explicits the far reaching effects plant pathogens

can have on region, politics, art, economics and

culture. Approximately, 1.5 million of victims died

as a result of either famine or the disease and rest

were forced to immigrate to North America.

History is rife with many such examples. Even

today, the crop yield losses on field and during

post harvest period caused by diseases and

insect pests are of paramount importance. The

annual loss can go up to 30 %. Even if a

conservative figure of 15% is considered, it

translates into a loss of 30 million tons of food

grain, 4 million tons of oilseed, 86 million tons of

sugarcane and 23 million tons of fruits and

vegetables annually. An annual loss of 60,000

crores has been estimated in India. Plant

protection is thus challenging, interesting and

important science. The amount of food loss

averted is a direct contribution to the food basket

of hungry millions. The advancements in averting

such looses thus has lots of bearing on the

growers, consumers and the society.

I will not go into the details about the topic

because it would be introduced to you more

appropriately by the Vice Chancellor.

However, I would like to mention that

Global food security and the different options

available to address the same are the major

concerns of the world today. Avoiding or

minimizing losses due to plant diseases could

significantly augment the overall food production

of the country. I would thus like to extend my

special gratitude to the Faculty of Plant Pathology

for their endorsement of the topic for the present

CAS training.

Finally, I would like to thank our Vice-

Chancellor for allowing us to hold this CAS

training.

With these words I welcome you all and

assure a fruitful and comfortable stay to the

participants of this 21th training programme of

CAS in Plant Pathology.

Thank you very much!

iii

INAUGURAL ADDRESS by

Prof. B.S. Bisht

Vice-Chancellor


on

December 13, 2008

I consider it a privilege and honour to

be called upon to Inaugurate the Training

Course “Recent Advances in Plant Disease

Management” being organized by the Centre

of Advanced Studies (CAS) in Plant

Pathology. I am delighted to know that as

many as 21 scientists from the SAUs and

Central Universities from all over India are

participating in the training course. I extend my

warm welcome to you all.

Plant disease epidemics have

influenced man’s food, his health, social

customs and even his ability to wage wars.

Human sufferings and epidemics of plant

diseases have gone hand in hand since the

earliest history of man. Even today,

catastrophic plant disease exacerbates the

current deficit of food supply in which at least

800 million people are inadequately fed.

India is being acknowledged as

growing economic giant but the benefits of

this progress are mostly confined to urban or

semi-urban areas. More than 65% of the

population in the country lives in rural areas

and depends on agriculture and related

avenues for their sustenance. Hunger and

poverty persists because of lack of work

opportunities, thus inadequate income for

farming community. Indian agriculture,

basically characterized as a means of

subsistence, is changing fast as per market

demands, both domestic and international.

Modern high input mono-cropping based

intensive agriculture has resulted in loss of

biodiversity (both flora and fauna), out-

breaks of pests and diseases, degradation of

soil and water, which has ultimately led to

stagnating agricultural production and

productivity. Climatic changes are becoming

a major factor in the present scenario.

Growing population of India that has

been putting more pressure on agro-

ecosystem for more food is a serous

concern. At the time of independence 350

million people lived in the country, which

after 60 years have grown to more than a

billion with more than 50% below the age of

30 years. As our food production is not

meeting the requirements, food is being

imported. By 2025, the food requirement is

likely to be doubled. Thus, more food will

have to be produced in ways that generate

income for poor rural populations and that also

make food affordable to poor people in urban

areas. Growing demand must be met

i

primarily by increasing production on land

already under cultivation (productive and

marginal lands) and by reducing losses due to

diseases and pests.

The crop yield losses, on field and

during post harvest period, caused by pests,

diseases and weeds are of paramount

importance. Diseases are critically important

components of agroecosystems globally, for

social, economic and biological reasons.

World wide annual losses due to diseases

are 25-30% of attainable production of

principle food and cash crops, with

developing countries experiencing the

greatest losses. It is estimated that out of the

total annual crop produce ($ 1500 billion),

approx. $ 550 billion is lost and another $38

billion is spent on pesticide alone to protect

augment the overall food production. Plant

diseases alone reduce global food

production substantially and the potato

disease that caused the Irish famine in 1845

is again becoming prevalent and resulting

into significant food losses.

Various types of direct and indirect

losses caused by plant diseases include,

reduced quality and quantity of crop

produce, increased cost of production, threat

to animal health and environment, limiting

the type of crops / cultivars grown, loss of

natural resources and less remunerative

alternatives adopted. In order to combat the

losses caused by plant diseases, it is

necessary to define the problem and seek

remedies. At the biological level, the

requirements are for the speedy and

accurate identification of the causal

organism, accurate estimates of the severity

of disease and its effect on yield, and

identification of its virulence mechanisms.

Disease may then be minimized by the

reduction of the pathogen's inoculum,

inhibition of its virulence mechanisms, and

promotion of genetic diversity in the crop.

Success in pest management, as in

most walks of life, depends on having the

right tools and the confidence to apply them.

The key tool for disease control is

knowledge and having knowledge gives

confidence. Diagnostic and advisory support

systems are facing massive challenges in

making relevant and effective knowledge

and support available to farmers and market

chains and ensuring that upstream

researchers are informed of the real priority

problems and issues requiring resolution.

Chemical pesticides have reduced

crop losses in many situations, but even with

a very substantial increase in pesticide use,

the overall proportion of crop losses and the

absolute value of these losses from pests

appear to have increased over time. Despite

this perverse relationship, an increase in

pesticide use still appears to be profitable.

Increased monoculture, reduced crop

diversity and rotation, and use of herbicide

have all boosted yields, but have increased

vulnerability to pests as well. Pests tend to

develop resistance to pesticides, requiring

higher use to sustain production.

Inappropriate and excessive pesticide use

have led to increased and unnecessary pest

ii

outbreaks and additional pest loss because

of the inadvertent destruction of natural

enemies of the pests, pest resistance, pest

resurgence, and secondary pests.

Ultimately, overuse of pesticide can reduce

food production. Proponents with varying

perspective on chemicals agree that IPM

must be science-based and economically

viable for farmers. The emphasis is on pest

problems and preventing them from reaching

economically damaging levels.

Current sensitivities about

environmental pollution are a consequence

of improper synthetic pesticide use. Host-

plant resistance, natural plant products, bio-

pesticides, natural enemies, and agronomic

practices offer a potentially viable option for

integrated pest management (IPM). They

are relatively safe for the non-target

organisms and humans. Biotechnological

tools such as marker assisted selection,

genetic engineering, and wide hybridization

to develop resistant crop cultivars will have a

great bearing on future pest management

programs. Disease modeling, decision

support systems, and remote sensing would

contribute to scaling up and dissemination of

IPM technologies.

Plant Pathology is challenging and an

important science that deals with science of

disease development (causes and

mechanism) and art of managing diseases

(minimizing the crop losses). Society,

consumers and growers will only be able to

continue to benefit from plant pathology if

the discipline can evolve appropriate disease

management schemes that can respond to

the significant changes in agricultural

practices in both industrial and developing

countries; the ultimate goal is to produce

more and safer food in sustainable

agricultural systems that conserve natural

resources and the environment. Information

technology, communication and the

integration of conventional and new

technologies are all essential elements that

must be integrated by the modern

practitioners of plant pathology into effective

disease management schemes that can be

implemented at the farm level.

In view of this, organization of the

current CAS training on Recent Advances in

Plant Disease Management should be viewed

as very timely and appropriate. I have, thus,

pleasure in declaring the training course

open and wish the training, discussions and

deliberations a grand success.

* * * * * * *

iii

(Recent Advances in Plant Disease Management)

- 1 -

DEPARTMENT OF PLANT PATHOLOGY

Establishment of University – 1960

Department created and Accredited – 1961

M. Sc. (Ag) Programme – 1963

Ph. D. Programme – 1965

Ist course – Introductory Plant Pathology

Ist Instructor – Dr. Y. L. Nene

Ist HOD – Dr. Y. L. Nene

Courses:

5 UG courses

16 PG courses

Staff position:

14 Professor

01 Honorary Professor

02 Professor (Guest Faculty)

04 Associate Professor

02 Assistant Professor

13 Technical staff

10 Supporting staff

The G.B. Pant University of Agriculture & Technology (earlier known as U.P. Agriculture

University) was established in 1960. Department of Plant pathology was created and accredited by ICAR

in 1961. The postgraduate degree programme leading to M.Sc. (Ag.) Plant Pathology and Ph.D. Plant

Pathology were started in 1963 and 1965, respectively.

Faculty of Plant Pathology is highly qualified and includes 14 professors, 1 Honorary Professor, 2

Guest Faculty, 4 Associate Professors and 2 Assistant Professor with 13 technical staff and 10

supporting staffs. Besides, there are two senior professors as guest faculty in the department

Sl. No. Name of Faculty members Designation Area of specialization

1. Dr. Serge Savary Honorary Professor Epidemiology

2. Dr. S.C. Saxena Guest Faculty Maize diseases

3. Dr. S.N. Vishwakarma Guest Faculty Vegetable & soybean

4. Dr. J. Kumar Professor & Head Plant disease management on small farm, IPM, Biological control, Molecular characterization of Plant Pathogens

5. Dr. K.P. Singh Professor Wheat


- 2 -

6. Dr. A.P. Sinha Professor Rice disease & fungicides

7. Dr. H.S. Tripathi Professor Pulse diseases & virology

8. Dr. R.P. Awasthi Professor Oilseed crop disease

9. Dr. K.S. Dubey Professor Soybean diseases

10. Dr. (Mrs.) K. Vishunavat Professor Seed Pathology

11. Dr. V.S. Pundhir Professor Epidemiology of crop disease

12. Dr. Pradeep Kumar Professor Maize Pathology

13. Dr. R. K. Sahu Professor Sugarcane diseases

14. Dr. Vishwanath Assoc. Professor Soybean Pathology

15. Dr. Yogendra Singh Assoc. Professor Sorghum diseases

16. Dr. K.P.S. Kushwaha Assoc. Professor Mushroom & pulse diseases

17. Dr. A.K. Tewari Assoc. Professor Oilseed crops diseases

18. Dr. K.K. Mishra Asstt. Professor Mushroom & pulse diseases

19. Dr. (Mrs.) Deepshikha Asstt. Professor Wheat diseases

TEACHING

The department of plant pathology has made immense contribution in the area of teaching,

research and extension. A well-knit UG and PG programme with updated and modern syllabi is

already in operation in the department. The department offers 6 courses for undergraduate

students. There are 20 postgraduate courses leading to M.Sc. (Ag.) and Ph.D. degrees in Plant

Pathology. Since the inception of the department 290 M.Sc. (Ag.) and 155 Ph.D. students have

been awarded degrees.

Under graduate courses:

1961’s Introductory Plant Pathology

Present

APP-312 Introductory Plant Pathology (2) APA/APP/APE-319 Organic Farming (2)

APP-314 Crop disease & their management (2) APP/APE-321 Integrated Pest Management (2)

APP-321 Mushroom cultivation (1)

Post graduate courses:

Core courses

APP-500 Principles of Plant Pathology (2) APP-520 Diagnosis of Plant Diseases (2)

APP-505 Phytopathological Techniques (2) APP-600 Seminar (1)

APP-515 Phytobacteriology (2) APP-690 Thesis Research (15)

APP-530 Phytovirology (2)

Basic Supporting Courses

BBB-625 Mycology I (3) BBB-626 Mycology II (3);


- 3 -

BPS-661 Experimental Statistics (4) BPM-502 Computer (2)

Optional courses – 6 Cr. Hr.

APP-610 Principle of Plant Disease Control (3)

APP-615 Seed Pathology (2)

APP-640 Fungicides (3)

APP-604 Diseases Resistance in Plants (2)

APP-612 Introduction to Edible Fungi (3)

APP-624 Cultural and Chemical Control of Plant Parasitic Nematodes (2)

APP-630 Phytonematology (2)

APP-602 Diseases of Ornamental and Medicinal Plants (2)

Deficiency Courses

For B. Sc. (Ag):

APP-410 Disease of Field Crops (3)

APP-430 Diseases of Horticultural Crops (3)

For ZBC:

APP-401 Introductory Plant Pathology (3)

APA-401 Elements of Crop Production (3)

APH-401 Introduction to Horticulture (3)

APP-410 Disease of Field Crops (3)

APP-430 Diseases of Horticultural Crops (3)

Ph.D. Courses:

APP-600 Seminar (1- 2)

APP-604 Disease Resistance in Plants (2)

APP-640 Fungicides (3)

APP-700 Epidemiology of Plant Diseases (2)

APP-710 Biochemistry of Plant Infection (2)

APP-720 Ecology of Soil Borne Plant Pathogens (3)

APP-790 Thesis Research (30)

Minor: 10 Cr.hr.

Books Published

The department has unique distinction of producing 33 books published by not only Indian

but also reputed international publishers like Elsevier Science (UK), Gordon and Beach (UK),

Prentice Hall (USA), CRC Press (USA), Science Publisher (USA), Lewis Publishers (USA) etc. It

has also produced 13 technical bulletins. A number of text books in Hindi for U.G. students have

been published. The faculty members have written/prepared several laboratory manuals,

reference books, working sheets on diseases, bulletins, extension pamphlets, etc. for the benefit of

U.G. and P.G. students of plant pathology as well as for the farmers.


- 4 -

(A) Hindi – (10) (B) English– (33)

Plant Disease 8th Edition by Dr. R.S. Singh

An Introduction to Principles of Plant Pathology 4th Edition by Dr. R.S. Singh

Plant Pathogens: The Fungi by Dr. R.S. Singh

Plant Pathogens: The Viruses & Viroids by Dr. R.S. Singh

Plant Pathogens: The Prokaryotes by Dr. R.S. Singh

Integrated Disease Management by Dr. R.S. Singh

Diseases of Fruit Crops by Dr. R.S. Singh

Fungicides in Plant Disease Control by Drs. P.N. Thapliyal and Y.L. Nene

Diseases of Annual Edible Oilseed Crops Vol.-I by Dr. S.J. Kolte

Diseases of Annual Edible Oilseed Crops Vol.-II by Dr. S.J. Kolte

Diseases of Annual Edible Oilseed Crops Vol.-III by Dr. S.J. Kolte

Diseases of Linseed & Fibre Flex by Dr. S.J. Kolte

Castor Diseases & Crop Improvement by Dr. S.J. Kolte

Plant Diseases of International Importance Vol.I: Diseases of Cereals & Pulses by

Drs. U.S. Singh, A. N. Mukhopadhyay, J. Kumar, and H.S. Chaube

Plant Diseases of International Importance Vol.II: Diseases of Vegetables & Oil Seed

Crops by Drs. H.S. Chaube, U.S. Singh, A. N. Mukhopadhyay & J. Kumar

Plant Diseases of International Importance Vol.III: Diseases of Fruit Crops by Drs. J.

Kumar, H.S. Chaube, U. S. Singh & A. N. Mukhopadhyay

Plant Diseases of International Importance Vol.IV: Diseases of Sugar, Forest &

Plantation Crops Drs A. N. Mukhopadhyay, J. Kumar, H.S. Chaube & U.S. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol.I: Prokaryotes by Drs. U. S.

Singh, Dr. Keisuke Kohmoto and R. P. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol. II: Eukaryotes by Drs. Keisuke

Kohmoto, U.S. Singh and R. P. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol. III: Viruses & Viroids by R. P.

Singh, U.S. Singh and Keisuke Kohmoto.

Aromatic Rices by Drs. R.K. Singh, U.S. Singh and G. S. Khush

A Treatise on the Scented Rices of India by Drs. R.K. Singh and U.S. Singh

Scented Rices of Uttar Pradesh & Uttaranchal by Drs. R. K. Singh and U.S. Singh

Plant Disease Management : Principles & practices by Drs. H.S. Chaube and U.S.

Singh

Molecular Methods in Plant Pathology by Drs. R. P. Singh and U.S. Singh

Soil Fungicides Vol.-I by Drs. A.P. Sinha and Kishan Singh

Soil Fungicides Vol.-II by Drs. A.P. Sinha and Kishan Singh

Experimental & Conceptual Plant Pathology Vol.I: Techniques by Dr. R.S. Singh, U. S.

Singh, W.M. Hess &D.J. Weber


- 5 -

Experimental & Conceptual Plant Pathology Vol. II: Pathogenesis and Host

Specificity by Dr. R.S. Singh, U. S. Singh, W.M. Hess & D.J. Weber

Experimental & Conceptual Plant Pathology Vol.III: Defense by Dr. R.S. Singh, U. S.

Singh, W.M. Hess &D.J. Weber

Seed Pathology, 2 volumes by Dr. V.K. Agarwal

Phytopathological Techniques by Dr. K. Vishunavat and S.J. Kolte

Crop Diseases & Their Management by H.S. Chaube & V.S. Pundhir

Laboratory Manuals published:

Introductory Plant Path (UG) : H. S. Chaube, V. S. Pundhir, S. N. Vishwakarma

Crop Diseases & Their Management : A. N. Tewari

Diagnosis of Plant Diseases : A. N. Tewari

Identification of Plant Disease

& their control

: A. N. Tewari

Phytovirology : Y.P.S. Rathi, H. S. Tripathi & P. Kumar

Introductory Plant Pathology (UG) : YPS Rathi, P. Kumar & H. S. Tripathi

RESEARCH

Research work in the department began since the inception of the University.

With the addition of new programme and staff strength, the research act ivit ies got

diversif ied encompassing, Ecology of soil borne plant pathogens, Epidemiol ogy and

Forecasting, Biological control and IPM, Molecular Biology and Populat ion Biology,

Seed Pathology, Fungicides, Nematology, Phytovirology, Phytobacteriology and

Biology & Technology of Mushroom Production. The department has several

research projects funded by national and international funding agencies. The

department is guiding the research work at the regional stat ion such as Bharsar,

Kashipur, Lohaghat, Majhera and Ranichauri on pathological aspects. The

scientists of the department have won many national and international awards.

The department is act ively engaged in the research work on both

fundamental and applied aspects in frontier areas of plant pathology. The plant

protect ion technology developed by the department is being effect ively

communicated to the farming community of state of Uttaranchal. The department

has to cater the needs of not only farmers of the plain but also of hil ls located at

different alt itudes. In hil ls crops, diseases and cropping pract ices vary a lot

depending on alt itudes and they are quite different from plain. This offers a big

challenge to the Centre of Advanced Studies in Plant Pathology.


- 6 -

Significant Contribution

Cause and control of Khaira disease of rice

Development of selective media for isolation and enumeration of Pythium and Fusarium

Mechanism of biological control in soil amended with organic matters

Biology and characterization of legume viruses

Ecology of soil – borne pathogens (Fusarium, Pythium, Rhizoctonia solani, Sclerotium rofsii)

Mechanism of absorption, translocation and distribution of fungicides in plants

Methods for quantitative estimation of fungicides like metalaxyl, organotin compounds, carbendazim

etc.

Hormonal action of fungicides

Phenolics in Plant disease resistance

Biological control with introduced antagonists

Etiology & management of mango malformation

Etiology and management of shisham wilt.

Epidemiology and Genetics of Karnal bunt fungus

Population biology of rice blast fungus, Magnaporthe grisea

Mechanism of intra-field variability in Rhizoctonia solani

Soil solarization

Mushrooms – Development of strains, and production technologies

Role of Ps. fluorescens in sporophores development of A. bisporus

Compost formulation with Sugarcane baggase + Wheat Straw, 2:1 developed to reduce cost of

cultivation of Agaricus bisporus.

Developed chemical treatment (Formalin 15ml + Bavistin 0.5g/10kg compost) of long method

compost to avoid the moulds in cultivation of A. bisporus.

Recommended supplementation of substrate with 2% mixture of Neem cake + Wheat straw + Rice

bran + Soybean meal for Pleurotus spp. cultivation.

Standardized cultivation of Auricularia polytricha using sterilized wheat straw supplemented with

wheat bran (5%).

Standardized cultivation of Lentinula edodes with substrate

popular sawdust.

Systemic induced resistance in brassicae.

Use of siderophore producing Pseudomonads for early fruiting

and enhanced yield of Agaricus bisporus.

Use of Pseudomonas fluorescens for control of mushroom

diseases caused by Verticillium, Sepedonium, Trichoderma and Fusarium.

Pleurotus sajor-caju and P. florida recommended for commercial cultivation using soybean straw /

Paddy straw / Wheat straw / Mustard straw.

Standardized cultivation technology for Hypsizygus almarius using wheat straw supplemented with

Lentinula edodes


- 7 -

wheat bran.

Standardized cultivation of Calocybe indica using wheat

straw as a substrate with casing of FYM + Spent Compost

+ Sand (2:1:1).

A relay cropping schedule developed for Tarai region of

Uttaranchal: two crops Agaricus bisporus (Sept. - March), four

crops Pleurotus spp. (Sept.- Nov. and Feb.,- April) and three

crops of Calocybe indica (March-October).

Developed two strains of Agaricus bisporus, Pant 31 and Pant 52, now included in multilocational

testing under coordinated trials.

Development and commercialization of seven hybrids of oyster mushroom.

Associated with multilocational testing and release of the strains NCS-100, NCS-102, NCH-102 of

A. bisporus.

120 mushroom species from different locations in Uttaranchal

have been collected and preserved in the museum of the

centre.

Of the collected mushrooms five Auricularia, four species of

Pleurotus and two species of Ganoderma have been brought

under cultivation.

Developed / standardized technology for production of traditional

value added mushroom products viz. ‘Sev’, ‘Warian’, ‘Papad’ and ‘Mathri’.

Isolated a high value cater pillar mushroom

Cordyceps sinensis from high altitudes of

Uttaranchal and analysed for antioxidative

properties.

MAJOR ACHIEVEMENTS

Twenty seven wheat lines, combining better agronomic characteristics and resistance to diseases

including Karnal bunt have been identified (Shanghi-4, BW 1052, HUW 318, Lira/Hyan’S’ VUI’S’,

CUMPAS 88, BOBWHITE, SPRW 15/BB/Sn 64/KLRE/3/CHA/4/GB(K)/16/VEE/ GOV/AZ/MU, NI9947,

Raj 3666, UP 1170, HS 265, HD 2590, HS317, PH 130, PH 131, PH 147, PH 148, PH 168, HW 2004,

GW 188, MACS 2496, CPAN 3004, K8804, K8806, ISWYN-29 (Veery”S”) and Annapurna).

Foliar blight of wheat has now been assumed as a problem in

Tarai areas of U.P and foothills of Uttaranchal. Bipolaris

sorokiniana - Dreschlera sorokiniana, was found associated

with the disease in this area. Karnal bunt of wheat caused by

Tilletia indica Mitra, is widely distributed in various Western

and Eastern districts of U.P while the North hills and Southern

Ganoderma lucidum

Cordyceps sinensis

Calocybe indica


- 8 -

dry areas are free from the disease.

Multiple disease control in wheat has been obtained by seed treatment with Raxil 2DS @

1.5g/Kg seed + one foliar spray fungicide Folicur 250 EW (Tebuconazole) @ 500ml/ha, which

controls loose smut, brown rust, yellow rust, powdery mildew and leaf blight disease very

effectively.

The mixture of HD 2329 + WH 542 + UP 2338 produced highest yield recording 11.67 per cent

higher as compared to average yield of their components.

Among new fungicides Raxil 2DS (Tebuconazole) @ 1.0, 1.5, 2.0 and 2.5g/kg seed, Flutriafol

and Dividend @ 2.5g/Kg seed were found highly effective in controlling the disease. Raxil 2DS

@ 1.5g/Kg seed as slurry treatment gave complete control of loose smut.

New techniques for embryo count and seedling count for loose smut, modified partial vacuum

inoculation method of loose smut, creation of artificial epiphytotics of Karnal bunt, NaOH seed

soaked method for Karnal bunt detection and detached leaf technique for screening against

leaf blight using pathogen toxin developed.

The major emphasis has been on the screening of maize germplasms to various diseases with

special reference to brown stripe downy mildew, banded leaf and sheath blight and Erwinia

stalk rot. A sick-plot has been developed to ensure natural source of inoculum. Efficient

techniques for mass multiplication of inoculum and screening of germplasms have been

developed to create epiphytotic conditions. The selected genotypes have been utilized for

evolving agronomically adaptable varieties. Several promising hybrids and composites have

developed and released following interdisciplinary approach.

Studies on estimation of yield losses, epidemiological parameters on various economically

important diseases of maize have been worked out to evolve suitable control measures and

have been recommended to farmers in the region.

Based on the survey and surveillance studies the information on the occurrence of various

diseases in UP and Uttaranchal, a disease map has been prepared and monitored to finalize the

out breaks of one or more diseases in a given area based on weather parameters. It will help the

growers to be prepared to save the crop from recommended plant protection measures.

An repository of >600 isolates of biocontrol agents developed at Pantnagar & Ranichauri.

These isolates are suited for different crops & agro-ecological conditions.

Standard methods developed for testing hyphal and sclerotial colonization.

Isolate of T. virens capable of colonizing sclerotia of Rhizoctonia, Sclerotium and Sclerotinia

isolated for the first time. It may have great potential.

16 new technologies related with mass multiplication and formulation of microbial bio-agents

developed and are in the process of being patented.

Several genotypes including SPV 462, SPV 475, SPV 1685, SPH 1375, SPH 1420, CSV 13,

CSV 15, CSH 14, CSH 16, CSH 18, G-01-03, G-09-03, GMRP 91, RS 629, UTFS 45, UTMC

523 and AKR 150 have been identified with high level of resistance to anthracnose and zonate


- 9 -

leaf spot diseases.

Biocontrol agents T. harzianum and P. fluorescens have been found effective in increasing the

growth of plants and reducing the severity of zonate leaf spot. G. virens and T. viride have

been found most effective against anthracnose pathogen.

The cause of Khaira as zinc deficiency was established for the first time and zinc sulphate

+slacked lime application schedule was developed for the control of the disease

Inoculation technique was developed to create “Kresek” phase in rice seedlings. Pre-planting root

exposure technique in a suspension of 108cells/ml for 24 hrs gave the maximum “Kresek”. Root

inoculation, in general was found better for development of wilt symptoms than shoot inoculation.

A simple technique has been developed to detect the pathogen in and/or on seeds. The

presence of viable pathogen has been demonstrated from infected seeds stored at room

temperature up to 11 months after harvest.

The disease is sporadic in occurrence often becomes serious in nature. Chemical control trials

showed that the disease can effectively be controlled by giving 2-3 foliar sprays of

streptocycline @ 15 g/ha.

A number of new fungicides along with recommended ones and botanicals were tested against

sheath blight. Foliar sprays with Anvil, Contaf, Opus, Swing and RIL F004 @ 2 ml/l and Tilt @

1 ml/l were found highly effective in controlling sheath blight. Foliar sprays with Neem gold @

20 ml /lit. or Neem azal @ 3ml/lit. was found significantly effective in reducing sheath blight

and increasing grain yield.

Foliar sprays with talc based formulations of the bioagents (Trichoderma harzianum, or

Pseudomonas fluorescence, rice leaf isolates) were found effective in reducing sheath blight

and increasing grain yield. Foliar sprays with the bioagents (T.harzianum) or P. fluorescence)

given 7 days before inoculation with R. solani was highly effective against the disease.

Seed or soil treatment with T. harzianum or P. fluorescence @ 2, 4 or 8 g/kg enhanced root

and shoot growth and fresh and dry weight of rice seedlings.

Seed treatment with fungorene followed by one spray of carbendazim (@ 0.05% at tillering at

diseases appearance) and two sprays of Hinosan @ 0.1% at panicle initiation and 50%

flowering was most effective and economical treatment in reducing the disease intensity and

increasing the yield.

For the first time, true sclerotia were observed in Kumaon and Garhwal regions at an altitude of

900 m above. True sclerotia have a dormancy period of approximately six months. Exposure of

sclerotia to near ultraviolet radiation for an hour breaks the dormancy and increased

germination.

Trichoderma may reduce population of earthworm in

vermicomposting during early days

An repository of >600 isolates of biocontrol agents developed at

Pantnagar & Ranichauri. These isolates are suited for different


- 10 -

crops & agro-ecological conditions.

Isolates of T. virens capable of colonizing sclerotia of Rhizoctonia, Sclerotium and Sclerotinia

isolated for the first time. It may have great potential.

Standard methods developed for testing hyphal and sclerotial colonization.

16 new technologies related with mass multiplication and formulation of microbial bioagents

developed and are in the process of being patented.

Effect of different physical factors and extracts on the germination of true sclerotia was studied.

Maximum germination was observed at 250 C and at pH 6.0, in fluorescent light. Among the

substratum, maximum germination occurred on moist sand. Soil extract was more favourable

than other extracts. The number of stipes and mature head formation was directly correlated

with the size and weight of the sclerotia.

The viability of the 3 propagules namely; conidia, pseudo and true sclerotia stored under

different conditions showed that conidia remain viable from 2-3 months, pseudo- sclerotia from

4-6 months and true sclerotia up to 11 months at room temperature and under field conditions.

True sclerotia buried at different depth (2.5 to 10 cm) in soil germinated well, but scleroita

buried at 15 cm depth did not germinate and rotted.

Discoloured grains of various types were grouped according to their symptoms. The fungi

responsible for each type of symptoms were identified. Ash grey discolouration of glumes

separated by dark brown band was caused by Alternaria alternata and Nigrospora oryzae.

Spots with dark brown margin and ash grey centre by Curvularia lunata and Alternaria

alternata, light yellow to light brown spots by C. pallescens, Fusarium equiseti and N. oryzae,

Brown to black dot by Phyllosticta oryzae Dark brown to black spot and specks by Drechslera

victoriae, D. rostratum and D. oryzae, light to dark brown glumes by Sarocladium oryzae and

D. oryzae, and light to dark brown spots by D. Australiense.

Rice varieties Manhar, Narendra 80, Saket 7, Ajaya, Bansmati, 385 showed higher incidence

(34.1 to 41.8%) whereas Sarju 52, UPR 1561-6-3, Pusa 44, Jaya, Pant Dhan 10 and improved

Sharbati exhibited lower (18.4-22.3%) incidence of seed discolouration. Bipolaris oyzae

caused highest seed discolouration which is followed by Fusarium moniliforme, curvularia

lunata and Fusarium graminium in all the test varieties.

On the basis of the symptoms pattern and transmissibility of the pathogen through grafting and

eriophyied mite (Aceria cajani), presence of foreign ribonucleic protein and nuclear inclusion

like bodies in the phloem cell indicated the viral (RNA virus) nature of the pathogen of sterility

mosaic of pigeon pea. The vector mite of the pathogen was found on lower surface of leaves

of Canavis sativus and Oxalis circulata weeds in this area. Mild mosaic, ring spot and severe

mosaic symptoms were observed in different as well as same cultivar. This observation reveals

the presence of variation in the pathogen.

Germplasm lines/ cultivars screened viz; ICP 14290, ICP 92059,ICP 8093, KPBR 80-2-2, PL

366, ICPL 371, Bahar, NP (WR) 15.were found resistan against Phytophthora stem blight.


- 11 -

Some resistant donors for mungbean yellow mosaic virus have been identified i.e. UPU-

1,UPU-2,UPU-3, UG-370, PDU-104, NDU-88-8, UG-737, and UG-774. The varieties thus

evolved include PU-19, PU- 30, and PU-35., Manikya, resistant lines/cultivars identified: ML-

62, ML-65, Pant M-4, Pant M-5, ML-131, NDM 88-14, ML-682, PDM-27, ML- 15, ML-803, ML-

682 and 11/ 395 and for Urdbean leaf crinkle virus, SHU 9504, -9513,-9515, -9516, -9520, -

9522, -9528, KU 96-1, UG 737 and TPU-4.

Seed treatment with carbendazim (0.1%) followed by two prophylactic sprays of carbendazim

(0, 05%) or Dithane M-45 @ 0.25% was found most effective in reducing disease severity of

anthracnose disease. In early sown crop high disease severity was observed while in late

sown crop low disease severity was recorded. Inter cropping with cereals or pulses have no

effect on anthracnose severity.

Propiconazol 0.1%, carbendazim 0.1%, hexaconazol 0.1%, mancozeb 0.25% sprayed plots

have low disease severity and high grain yield against Cercospora leaf spot.

Studies on integrated management of wilt/root rot/collar rot showed that Seed treatment with

fungicide alone or in combination with other fungicides/ bio agents were found effective.

Among the fungicides seed treatment with Bavistin + Thiram (1:2), vitavax + Thiram (1:2),

vitavax, Bavistin, Bayleton, Bio agent Gliocladium virens + Vitavax and Pseudomonas

fluorescence) decreased the seedling mortality, improved germ inability, plant stand and yield.

Ten thousand germplasm lines/ breeding populations F2, F3,

F4 and F5 generations were screened. Many germplasm/

accessions were found resistant/ tolerant to Botrytis gray

mould viz; ICC 1069, ICC 10302, ICCL 87322, ICC 1599, -

15980, - 8529, ICCV 88510, E100Y (M) BG 256, BG261,

H86-73, IGCP 6 and GNG 146.

Lentil entries evaluated under sick plot for wilt/root rot/ collar

rot diseases. The following lines were found promising viz;

LL 383, PL 81-17, LH 54-8, DPL-58, DPL 14, Jawahar Massor- 3, DPL 112, IPL-114, L 4147

and Pant L 639.

The promising germplasm lines/ cultivars are as follows: DPL 62, PL-406, L 4076, TL 717, E

153, IPL 101, IPL 105, PL- 639, LH 84-8, and Precoz .

The field pea lines were found promising JP 141, Pant P-5, KFPD 24 (swati), HUDP 15, KFPD-

2, HFP-4, P1361, EC-1, P-632, P 108-1, KPMR 444, KF 9412, DPR 48, T-10, KPMRD348,

DDR13, IM9102, KFP 141 and KPMR 467 against powdery mildew and JP 141, Pant P-5, P

10, FP 141, KDMRD 384, HUDP-9, HUP-2 and T-10 were found promising against rust

disease.

Mid-September planting or early October planting of rapeseed-mustard has been found to

escape from Alternaria blight (Alternaria brassicae) downy mildew (Peronospora parasitica)

and white rust (Albugo candida) diseases as against mid and late October planting. In general


- 12 -

high occurrence of the floral infection (staghead phase) of white rust and downy mildew during

flowering period has been found to be associated with reduced period, i.e. 2-6 hours, of bright

sunshine/day concomitant with the mean maximum temperature of 21-250C, the mean

minimum temperature of 6-100C and higher total rainfall up to 166 mm. Bright sunshine hours

/day has a significant negative correlation whereas total rainfall has a significant positive

correlation with staghead development.

All the three important foliar diseases of rapeseed-mustard could be effectively controlled by

following integrated package of balanced N100 P40K40 application, early October sowing and

treating the seed with Apron 35 SD @ 6g kg-1 seed followed by spray of mixture of metalaxyl +

mancozeb (i.e Ridomil MZ 72 WP @ 0.25%) at flowering stage and by spray of mancozeb or

iprodione @ 0.2% at pod formation stage. In situations where Sclerotinia stem rot and / or

powdery mildew appeared to be important in a particular crop season, a spray of mixture of

carbendazim (0.05%) + mancozeb (0.2%) was found to give excellent cost effective control of

the diseases with significant increase in seed yield of the crop.

Among the botanicals, leaf extracts of Eucalyptus globosus (5%) and Azadirchta indica (5%)

have been proved to exhibit greater antifungal activity against A. brassicae and Albugo

candida and showed significant reduction in the severity of Alternaria blight and white rust

diseases which was rated to be at par with mancozeb fungicide spray.

Some abiotic chemical nutrient salts such as calcium sulphate (1%), zinc sulphate(0.1%) and

borax (0.5%) and biocontrol agents such as Trichoderma harzianum and non-aggressive D

pathotype of A.brassicae have been shown to induce systemic host resistance in mustard

against aggressive “A” pathotype of A. brassicae and virulent race(s) of A. candida.

The staghead phase in B. juncea has been investigated to be due to A. candida and not due P.

parasitica. Tissues at the staghead phase become more susceptible to P. parasitica than

normal tissues of the same plant.

B. juncea genotypes (EC 399296, EC 399299, EC 399301, EC 399313, PAB-9535, Divya

Selection-2 and PAB 9511), B. napus genotypes (EC 338997, BNS-4) and B. carinata (PBC-

9221) have been shown to possess resistance to white rust coupled with high degree of

tolerance to Alternaria blight. Reduced sporulation is identified to be the major component for

slow blighting.

B. juncea (RESJ 836), B. rapa (RESR 219) and B. napus (EC 339000) have been selected for

resistance to downy mildew and for high yield performance. Total 52 genotypes of mustard

representing at least 12 differential resistance sources, 23 lines of yellow sarson representing

6 differential resistance sources and 54 lines of B. napus representing 3 differential resistance

sources to downy mildew have been identified.

A new short duration (95-100 days) short statured (85- 96 cm) plant type of mustard strain

‘DIVYA’ possessing high degree of tolerance to Alternaria blight suitable for intercropping with

autumn sown sugarcane and potato yielding with an average of 15-22 q ha-1 has been


- 13 -

developed. This ‘Mustard DIVYA’ plant type is now recommended as a source for breeding

more and more improved varieties of mustard as it has been proved to have good general

combining ability for short stature characteristics.

Seed treatment with mancozeb @ 0.2% + thiram @ 0.2% has been found to control seed,

seedling and root rot diseases of groundnut. However seed treatment with thiram @ 0.2% +

vitavax @ 0.2% has been found to control collar rot (Sclerotium rolfsii) of groundnut. Two

sprays of carbendazim @ 0.05% have been found to give excellent control of early and late

leaf spot (tikka disease) of groundnut.

Mid September planting of sunflower was found to escape the occurrence of major diseases

like Sclerotinia wilt and rot, Sclerotium wilt, charcoal rot and toxemia. Severity of Alternaria

blight was found to be negligible and did not cause any reduction in yield. The crop could be

harvested by 15th December. The yield obtained was 16 q/ha.

The average percent loss has been noted in the range of 50.6 to 80.7 percent due to Alternaria

blight disease under Kharif conditions. However, the percent loss in oil has been shown in the

range of 21.6 to 32.3. To control the disease, total 4 sprays of mancozeb @ 0.3% at 10 day

interval have been found effective.

A repository of about 5000 rice blast isolates was made from 30 locations in Indian Himalayas at

Hill Campus, Ranichauri. Blast pathogen population from the region was analyzed using molecular

markers and phenotypic assays. Most locations sampled and analyzed had distinct populations

with some containing one or a few lineages and others were very diverse. Within an

agroecological region migration appeared to be high. The structure of some populations could be

affected to some extent by sexual recombination.

Magnaporthe grisea isolates derived from Eleusine coracana, Setaria italica and Echinochloa

frumentaceum collected from a disease screening nursery were cross compatible. The

chromosome number of each isolate was found to be six or seven. Similarity of karyotypes was

found among isolates with in a lineage though between lineages some variability was noticed. A

remarkable similarity between karyotypes of Eleusine coracana and Setaria italica was observed. All

of these isolates were fertile and mated with each other to produce productive perithecia. The

existing data however showed no evidence of genetic exchange among host-limited M. grisea

populations in Indian Himalayas.

No strong relationship appeared between the number of virulences in a pathotyope and its frequency

of detection. The frequency of virulent phenotype to a cultivar and susceptibility of that cultivar in the

field did not correspond. The number of virulences per isolate was in general less than the number

of virulences per pathotype, which indicated predominance of isolates from pathotypes with fewer

virulences. There was a tendency for the pathotypes to have fewer virulences. The frequency of

virulence among rare pathotypes was higher than common pathotypes against all the differential

NILs, including two-gene pyramids. These rare pathotypes could be the potential source of

resistance breakdown of the novel resistance genes.


- 14 -

Blast resistant gene Pi-2(t) appeared to have the broadest and Pi-1(t) the narrowest resistant

spectra. Compatibility to Pi-2 (t) gene did not appear to limit compatibilities with other resistant

genes. Loss of avirulence to all the five major gene tested may carry a serious fitness penalty.

Major gene Pi-2 and gene combination Pi-1,2 showed least compatibilities and hold promise

in managing blast in the region. In the overall Himalayan population, gene combinations in

general were effective at most locations. Combination of Pi-1+2 genes was effective at most

locations until the year tested. However, three gene pyramid [Pi-1(t) + Pi-2(t)+Pi-4(t)] resisted

infection at all locations.

It was inferred that the pathotype composition of the blast pathogen composition in the Indian

Himalayas was very complex and diversifying the resistance genes in various rice breeding

programmes should prove to be a useful strategy for disease management.

A common minimum programme under bio-intensive IPM in vegetables in Uttaranchal hills was

designed that is extended to over 2000 farmers from 20 villages in district Tehri Garhwal.

Epidemiological considerations in the apple scab disease management led to the development

of disease prediction models. Relation of degree-day accumulations to maturation of

ascospores, and potential ascospore dose (PAD) were found to be useful for predicting the

total amount of inoculum in an orchard thereby effectively improving apple scab management.

Out of 71 genotypes tested against red rot caused by Colletotrichum falcatum, four genotypes

viz; Co Pant 92226, Co Pant 96216, Co Pant 97222 and CoJ 83 were found resistant and

another 24 exhibited fairly good tolerance.

Seed treatment with Thiram + Carbendazim (2:1) @ 3g/kg seed or Vitavax 0.2% controlled the

seed and seedling rots and improved the seedling emergence without any adverse effect on

the nodulation and invariably yield were increased. Seed treatment with Trichoderma

harizianum, T. viride or Pseudomonas fluorescens @ 10g/kg controlled seed and seedling rots

and increased plant emergence.

Purple seed stain disease can be effectively controlled by seed treatment with thiram +

carbendazim (2:1) @ 3 g/kg seed followed by two sprays of benomyl or Carbendazim @ 0.5

kg/ha.

Rhizoctonia aerial blight can be effectively controlled by two sprays of carbendazim @ 0.5

kg/ha. Seed treatment with T. harzianum or Pseudomonas fluorescens 10g/kg seed + soil

treatment with pant Bioagent-3 mixed with FYM @50q/ha followed by two sprays of T.

harzianum @ 0.25% reduced the disease severity of RAB.

Pod blight and foliar diseases caused by Colletrotichum dematium var truncatum could be

effectively controlled by the use of carbednazim 0.05%, Mancozeb 0.25%, Copperoxychloride

0.3%, Thiophanate methyl 0.05%, Chlorothalonil 0.25%, Hexaconazole 0.1% and


- 15 -

Propiconazole 0.1%. First spray should be given as soon as disease appear and second spray

after 15 days of first spray.

Rust disease could be effectively controlled with three sprays of Benomyl 0.05%, Mancozeb

0.25% or Zineb 0.25%, at 50, 60 and 70 days after sowing. Varieties Ankur, PK-7139, PK-

7394, PK-7121, PK-7391 were resistant.

Charcoal rot disease can be effectively controlled by seed treatment with Trichoderma

harzianum @ 0.2% + vitavax @ 0.1%.

Pre-mature drying problem Soybean can be minimized by seed treatment with carbendazim +

Thiram (2:1) @ 3g/kg seed followed by two sprays with carbendazim, mancozeb and

Aureofungin. Varieties PSS-1, PS-1042, PK-1162, PK-1242 and PK-1250 were found to be

superior for premature drying problem.

Integrated disease management (IDM) modules based on combined use of cultural practices,

fungicides for fungal disease, insecticide for virus disease and host resistance were evaluated

against RAB and Soybean yellow Mosaic virus diseases.

Bacterial pustules can be successfully controlled by two sprays at 45 and 55 days after

planting with a mixture of Blitox-50 (1.5 kg/ha) + Agrimycin-100 (150g/ha) or streptocycline

(150 g/ha) + copper sulphate (1kg/ha).

Soybean yellow Mosaic can be very effectively controlled by four sprays with oxymethyl

demoton @ 1l/1000 lit/ha at 20, 30, 40 and 50 days after planting. Soil application with Phorate

10G @ 10 kg/ha and Furadan 3G @ 17.5 kg/ha controlled the disease. Varieties PK-1284,

1251, 1259, 1043, 1225, 1303, 1314, 1343, 1347, PS-1042 PS-564, 1364 were identified as

resistant to Soybean yellow Mosaic virus.

EXTENSION

The scientists also participate in the farmers contact programme as well as practical

trainings at different levels including those of IAS and PCS officers, Extension workers, Agricultural

officers, Farmers, Defense Personnels etc. The Scientists of the department also actively

participate in the trainings organized under the T&V programme for the benefit of farmers/State

level Agricultural Officers. Two Professors (Extension Pathology) and crop disease specialists are

deputed to “Help Line Service” started recently by the University under Agriculture Technology

Information Centre (ATIC). The telephone number of help line services is 05944-234810 and 1551.

Technology developed by the centre is regularly communicated to the farmers of the 13 districts of

Uttaranchal State through the extension staff (Plant Protection) of both university and state

agriculture and horticulture departments posted in all districts of the state. The radio talks and TV

programme are delivered. Popular articles and disease circulars are published regularly for the

benefit of the farmers.


- 16 -

UP-GRADATION TO CENTRE OF ADVANCED STUDIES

In view of the outstanding quality of teaching, research and extension work being carried out by

the department, ICAR vide letter No. 1-2/93 (CAS)UNDP dated Feb.02, 1995 upgraded the department

to the status of the centre of advanced studies in plant pathology. Major mandate of the CAS was to train

scientific faculty from all over the country in important and innovative areas of plant pathology. So far

under CAS, 16 trainings have been conducted and 336 scientists from all over the country have been

trained in different areas. Centre of Advanced Studies in Plant Pathology at Pantnagar was awarded a

certificate of Appreciation in commemoration of Golden Jubilee year of independence (1998) for

organizing the programmes for human resource development and developing excellent instructional

material by the education division, ICAR on August 14, 1998. The progress report CAS in Plant

Pathology during X plan is as follows:

Trainings Held

1. Recent advances in biology, epidemiology and management of diseases of major kharif

crops (Sept. 19- Oct. 12, 1996)

2. Recent advances in biology, epidemiology and management of diseases of major rabi crops

(Feb. 25 –March 18, 1997)

3. Ecology and ecofriendly management of soil-borne plant pathogens (Jan 12 – Feb. 02, 1998)

4. Advanced techniques in plant pathology (Oct. 12 – Nov. 02, 1998)

5. Recent advances in detection and management of seed-borne pathogens (March 10-30,

1999)

6. Recent advances etiology and management of root-rot and wilt complexes (Nov. 26 – Dec.

16, 1998)

7. Integrated pest management with particular reference to plant diseases: concept, potential

and application (Nov. 23 –Dec. 13, 2000)

8. Recent advances in research on major diseases of horticultural crops (March 01-30, 2001)

9. Recent advances in plant protection technology for sustainable agriculture (Nov. 19 –Dec.

09, 2001)


- 17 -

10. Plant diseases diagnosis: past, present and future (Feb. 13, - March 05, 2002)

11. Chemicals in plant protection: past, present and future (Jan. 28 – Feb. 17, 2003)

12. Eco-friendly management of plant diseases of national importance: present status and

research and extension needs (Nov. 10-30, 2003)

13. Ecologically sustainable management of plant diseases: status and strategies (March 22-

April 11, 2004)

14. Disease resistance in field and horticulture crops: key to sustainable agriculture (Dec. 10-30,

2004)

15. Regulatory and cultural practices in plant disease management (Dec. 03-21, 2005)

16. Crop disease management: needs and outlook for transgenics, microbial antagonists and

botanicals (March 21 – April 10, 2006)

17. Soil Health and Crop Disease Management (December 02-22, 2007)

18. Role of Mineral Nutrients and Innovative Eco-friendly Measures in Crop Disease

Management (March 22- April 11, 2007)

19. Plant Disease Management on Small Farms (January 03-23, 2008)

20. Seed Health Management for Better Productivity (March 28 to April 17, 2008)

21. Recent Advances in Plant Disease Management (Dec. 13, 08 to Jan. 02, 09)

Sl. No.

State Total Sl. No.

State Total

1. Andhra Pradesh 11 13. Maharashtra 25

2. Assam 09 14. Manipur 03

3. Bihar 17 15. Meghalaya 01

4. Chattishgarh 7 16. Nagaland 01

5. Gujarat 41 17. Orissa 12

6. Haryana 3 18. Punjab 04

7. Himanchal Pradesh 34 19. Rajasthan 40

8. Jammu & Kashmir 24 20. Sikkim 01

9. Jharkhand 06 21. Tamil Nadu 11

10. Karnataka 22 22. Uttar Pradesh 58

11. Kerla 05 23. Uttaranchal 62

12. Madhya Pradesh 22 24. West Bengal 17

Total = 436


- 18 -

INFRASTRUCTURE

Wheat Pathology Lab. – General Path, Epidemiology, Toxin, Tissue Culture

Maize Pathology Lab. – General Plant Pathology, Bacteriology

Rice Pathology Lab. – General Plant Pathology

Ecology and Vegetable Pathology Lab. – Ecology, Histopathology, Biocontrol, Nematodes

Soybean Path. Lab.– General Plant Pathology, Fungicides

Oil Seed Path. Lab.– General Pl. Path., Tissue, Culture, Histopathology, Toxins

Pulse Path. Lab. – General Pl. Path., Phytovirology

Seed Path. Lab. – General Path, Seed Borne diseases

Biocontrol Lab. – Biocontrol & IPM

Molecular Pl. Path Lab. – Population biology & host- pathogen interaction

Mushroom Research – Research & training

Glass houses – 3

Polyhouses – 3

UG Practical Lab – 1

PG Lab – 1

Training Hall – 1

Conference Hall – 1

Office – 1

Huts for Mushroom Production


- 19 -

Research Project (on going)

AICRP – 13

Adhoc Projects – 16

Total budget outlay - > 1000 lacs

Sl. No. Project title Funding

agency

1 All India Coordinated Research Project on Wheat ICAR

2 All India Coordinated Research Project on Rice ICAR

3 All India Coordinated Research Project on Maize ICAR


- 20 -

4 All India Coordinated Research Project on Rapeseed Mustard ICAR

5 All India Coordinated Research Project on MULLaRP ICAR

6 All India Coordinated Research Project on Sugarcane ICAR

7 All India Coordinated Research Project on Sorghum ICAR

8 All India Coordinated Research Project on Biological control ICAR

9 All India Coordinated Research Project on Soybean ICAR

10 All India Coordinated Research Project on Mushroom ICAR

11 All India Coordinated Research Project (NSP) Seed Tech Research ICAR

12 Application of micro-organism in Agriculture and Allied Sector Fungi of

Uttaranchal

ICAR

13 All India Coordinated Research Project on Potato ICAR

14 Integrated Management of Guava wilt ICAR, MM-I

15 IPM in Vegetables ICAR, MM-I

16 Refinement of Technology for Production of specialty mushroom ICAR, MM-I

17 Ganoderma of Uttaranchal: their cultivation and components of

medicinal uses

ICAR, MM-I

18 Multilocational Evaluation on Rice germplasm NBPGR-ICAR

19 IPM NCIPM

20 Rural Bio-resource Complex DBT

21 Study of Pathogenicity & Molecular Variability in Fusarium solani

causing shisham wilt

DBT

22 Centre of Excellence in Agriculture Biotechnology DBT

23 Management of crop performances through control of plant disease

epidemics (Indo-French Program) (Just approved)

CEFIPRA,

France

24 Further studies on the management of Karnal Bunt by eco-friendly

Means

Adhoc

25 Multi-locational Evaluation of the germplasm in Chickpea Adhoc

26 Evaluation of Chickpea germplasm against biotic stress -BGM Adhoc

27 DUS test on forage sorghum Adhoc

28 Net work project on management of Alternaria blight of mustard and

vegetable crops

Adhoc

29 Indo-UK Collaborative Project on oilseeds for transfer of disease and

draught resistant

Adhoc

30 AIC Epidemiology and Plant disease management Adhoc


- 21 -

Total Budget Outlay – > 1000 lakhs

Research Areas – Biological Control, IPM, Shisham wilt, Soil solarization, Population Biology,

Seed pathology, Mushroom etc.

Publication:

1. Books - 33

2. Research Bulletins - 20

3. Research Papers - >1200

4. Conceptual / Review articles - >130

5. Chapters contributed to book - >150

6. Extension literature - over (200)

(Hindi – English)

Annual Review of Phytopathology - 02

Recognition and Awards:

UNO (Rome) – Dr. Y. L. Nene

Prof. M. J. Narisimhan Academic Award (IPS) 5

Jawahar Lal Nehru Award (ICAR) 2

Pesticide India Award (ISMPP) 7

P. R. Verma Award for best Ph. D. Thesis (ISMPP) 2

Other (Hexamar, MS Pavgi, Rajendra Prasad etc.) >20

Uttaranchal Ratana 2

Education Award 2004-05” for his book “Qyksa ds jksx” 01

by the Ministry of Human Resource Development, GOI

Professional Societies and our Share:

Indian Phytopathological Societies

Presidents – 3

Zonal Presidents – 3

Indian Society of Mycology & Plant Pathology –

Presidents – 3

Vice Presidents – 1

Indian Soc. Seed Technology

Vice Presidents - 3

Science Congress

President (Agriculture Chapter) - 1

National Academy of Agricultural Sciences

Fellows - 3


- 22 -

Future Strategies:

Teaching: Introduction of new courses

Methods in Biological Control

Plant disease and national importance

Integrated plant disease management

Molecular plant pathology

Advances in mushroom production

Research thrust:

• Biological control & ICM (IPM + INM) in different crops/cropping systems

• Disease management under organic farming

• Microbial ecology

• Green chemicals

• Population biology of pathogens (including use of molecular tools)

• Induced resistance

• Exploitation of indigenous edible and medicinal mushrooms

Human Resource Development

Degree awarded

M.Sc. 285

PhD 155

Trainings organized No. Persons trained

Summer schools (ICAR) 5 136

Summer training (DBT) 1 24

International training (IRRI) 1 11 (8 countries)

Under CAS 20 416

Persons training under SGSY on Mushroom Production 1785

Out of above > 750 persons have started mushroom cultivation

Future Goal:

Ecologically sustainable management of plant diseases to ensure both food security &

safety through education, research & extension


- 23 -

Addressing Nutrient Deficiencies and Toxicities in Crops

P.C. Srivastava Department of Soil Science, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

The growth of crop plants depends upon a number of soil, climatic and management

factors. Nutrient supply to plants play very important role in plant growth and ultimate crop yield

and quality of produce. When crops fail to absorb any nutrient in sufficient quantities, the metabo-

lism disturbances occur and crops exhibit specific hunger signs. These hunger signs are called

deficiency symptoms, which appear depending upon the mobility of nutrient in plants. Deficiency

symptoms of nitrogen, phosphorus, potassium, magnesium, molybdenum and zinc appear first on

older leaves. The deficiency symptoms of calcium, boron, manganese iron and sulphur appear first

on new leaves and buds. On the other hand, if some of these nutrients are present in excess they

produce toxicity symptoms and require immediate adoption of corrective measures.

Management of nutrient deficiencies in the field requires a thorough knowledge of the

symptoms produced as a result of deficiency or toxicity of the specific nutrient. For the

amelioration of deficiency, corrective measures need to be adopted based on the principles of

integrated nutrient supply system.

Nutrient toxicities especially, in respect of micronutrients are important in certain

geographical regions and can be best managed by using tolerant varieties and chemical

amendments.

Components of nutrient supply system:

In agricultural ecosystem, major sources of plant nutrients are:

Soil

Mineral fertilizers

Organic manures/matter

Amendments

Biofertilizers.

The main aim is to tap all possible sources in a judicious way and ensure their efficient use.

A Soil source

In order to enhance the supply of nutrients from soil, the following measures need to be

adopted.

Adoption of appropriate soil management and conservation practices to reduce nutrient loss.

Amelioration of problem soils to mobilize unavailable nutrients

Maximum utilization of available soil nutrients using appropriate crop variety, cultural practices and cropping system

Microbiological methods to mobilize unavailable soil nutrients using vesicular-arbuscular mycorrhizae and Psuedomonas spp.

B. Chemical fertilizers

More efficient use of chemical fertilizers in the production system is intended. In a country

like India where the problems of low and unbalanced fertilizer use and food requirement of an


- 24 -

ever increasing population coexist, any approach to further reduce the fertilizer application and

supplementation through alternative sources should be advocated with great caution

depending upon the current level of fertilizer use in the system. The direction should be to

maximize production/unit area/unit time by optimizing fertilizer use efficiency through

complementary use of organics and other alternative sources of plant nutrients. Any additional

nutrient applied through other sources must be taken into account for making up the gap

between the recommended and actual level of fertilizer application.

Higher fertilizer use efficiency can be achieved through:

Use of appropriate fertilizer product

Minimization of nutrient loss by using correct method and time of application

Elimination of all nutritional limiting factors such as primary a- and secondary-nutrients

and improvement in other production factors

Scheduling of fertilizer recommendations

C. Organic manures

Organic manure/matter is valuable bye-product of farming and allied industries. The

nutrient recycling is possible either by their composting or direct application or mulching. Some

of such sources are-

Farmyard manure, poultry litter, sheep and goat droppings.

Crop residues.

Municipal wastes (Night soil, urine, sewage, sludge)

Slaughter house (blood, bones) and fishery wastes

Bye-products of agro-industries (oil cakes, fruit and vegetable processing wastes, press-mud rice-husk, bran)

Forest litter, marine algae, sea weeds, water hyacinth, tank silt etc.

D. Biofertilizers

Suitable microbial culture should be used to tap unavailable soil nutrients. Besides

improving the availability of N to plants, green manuring/leguminous tree leaf manuring and

use of symbiotic and asymbiotic microorganisms also alter the supply of micronutrients. This

involves use of vesicular-arbuscular mycorrhizae and suitable strains of Psuedomonas spp.

Microbes capable of producing growth promoting, antifungal and antibacterial substances can

also be used. A combined inoculation strategy can be adopted to partly reduce the

dependence on chemical fertilizers. This involves an integration of a combination of inoculants

with reduced doses of mineral fertilizers to meet the complete requirement of the crop under a

given agro-climatic condition. The strategy has important relevance in organic farming.

REFERENCES

1. Tisdale, S.L.; Nelson, W.L.; Beaton, J.D. and Havlin, J.L. 1997. Soil Fertility and Fertilizer. 5th ed.

Prentice hall of India.

2. Srivastava, P.C. and Gupta, U.C. 1996. Trace elements in crop production. Oxford. IBH publishing.


- 25 -

GIS Application in Precision Farming and Plant Disease Management

A.K. Agnihotri Department of Soil Science, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Introduction to Gis

DEFINITION

Definitions of GIS (short for "Geographic Information Systems") vary considerably.

One such definition is as follows.

GIS is a computer-based information management technology used by people for handling

spatial/geographic data or geographically-referenced data.

There are two important aspects in the definition of GIS:

Components of GIS

There are four basic components of a GIS - i.e., people managing data by formulating tasks using

software running on hardware.

Functions of GIS

With these basic components, GIS can be used to perform the following functions:

Data handling (i.e. capturing, organizing, storing)

Data manipulation (i.e. processing, analyzing)

Data output (i.e. displaying)

GIS Applications

GIS as an information management tool can be used over a spectrum of developmental

stages from the most basic to the most sophisticated. GIS techniques can be applied to a wide

variety of problem-solving situations in practically any field of human endeavor where maps or

geographical information are used.

Three basic types of GIS applications that represent the stages of development (with

increasing sophistication) in the use of GIS technology are

1 inventory applications,

2 analysis applications, and

3 management applications.

At its most basic level, GIS is used as an information management tool - a method of

integrating spatial data (e.g., maps and satellite images) and textual/tabular data (e.g., census,

soils, and climate) within a single, retrievable data base. At the advanced level, GIS can be used

as a tool for modeling and testing hypotheses, such as on land/resource use scenarios, ecosystem

change and evaluation of technology suitability.

Inventory Applications

Often the first step in developing a GIS application is making an inventory of the subjects

you want to study for a given geographic area, e.g. soils, land cover/land use, human settlements,

infrastructure, etc. These subjects are represented in the GIS as layers or themes of data. At this


- 26 -

basic level, the GIS is used as an information handling tool --- a method of integrating spatial data

( e.g., maps and satellite images) and textual/tabular data ( e.g., census, soils, and climate) within

a data base whereby the component layers may be retrieved, displayed, printed out and updated.

Analysis Applications

Once the GIS data base is set up, you would usually want to get value-added information

from the data. This can range from carrying out simple to complex queries involving multiple data

layers to more complex analysis on the data layers. Most GIS have a variety of spatial analysis

tools to manipulate map layers and their associated data.

Management Applications

More advanced spatial analysis and modeling techniques are needed to address real world

problems. At this stage of application, GIS, on its own or linked with other tools, may be used to

help managers and policy makers in making decisions based on a rational use of a sound

knowledge base.

WHAT YOU CAN DO WITH A GIS?

Identifying Features

With a GIS, you can ask questions about the data sets created. There are two main kinds of

questions that the GIS can answer:

I. Querying - what exists at a particular location?

You specify the object/feature for which you want information by

o pointing at an object or region of a displayed map

o typing the identifier for the object you select

o typing in a geographical coordinate location

After specifying the object/feature or location, you can obtain a list of

o all of its characteristics some of its characteristics

o some of its’ characteristics

2. Locating by specifying conditions - where are the objects/features which satisfy a particular

set of conditions?

You can specify one condition or a set of conditions by stringing them up in logical expressions.

Performing Geographical Analyses

You can analyze data to obtain.

o answers to a particular question

o solutions to a particular problem

GIS can carry out many different types of spatial operations on the data stored in the GIS data

base, or on data from other software which are linked to the GIS data sets.

Spatial operations may be applied to.

o existing map(s)

o attribute data associated with existing map(s)


- 27 -

The result of spatial operations may be.

o new map(s)

o tabular data

o graphics, e.g. line graphs, bar charts, etc..

When spatial operations are performed on two or more map layers, we refer to the operations as

map overlays. Spatial operations performed on multiple map layers may be thought of as map

algebra. The map algebra concept is an extension of the algebra operation on numbers.

Instead of operating on single numbers, the spatial operator acts on whole map layers. In

the raster mode, the operator acts on the geographically equivalent cells of the map layers.

By stringing together various spatial operations, the GIS can be used to solve complex

problems using geographically-referenced data.

Concept of Map Overlays

Vector mode Raster mode


- 28 -

THE NATURE AND REPRESENTATION OF GEOGRAPHIC DATA

THE NATURE OF GEOGRAPHIC DATA

The world is infinitely complex and full of variation; the closer one looks, the more detail is seen,

ad infinitum. It would therefore take an infinitely large data base to represent the real world

accurately. Therefore data must somehow be reduced to a finite and manageable quantity by

abstraction and generalization. Real-world entities must be represented by discrete objects with

associated attributes and geographical data must give information about

a. position

b. attribute

c. possible topological relationships

Spatial objects representing real-world entities with finite area. The real-world entities

which are represented as areas also depend on the scale of the map ( e.g., on a large scale map,

streams are represented by areas, although slim, elongated areas while on a small scale map,

streams are represented by lines). Boundaries may be natural or man-made.

REPRESENTATION OF GEOGRAPHIC OBJECTS IN COMPUTERISED GIS

In computerized GIS, map information that we normally see in paper maps would need to

be converted to digital form.

Analog Representation

This is more familiar to ordinary users of maps. Points, lines, and areas are drawn with a

certain amount of locational accuracy on a 2-D surface like a piece of paper, and referenced to

locations on the earth's surface by using some standard system of coordinates, e.g. national grid,

or an internationally-accepted map projection. Objects drawn on the map may be stylized and

symbolized or color-coded, attributes may also be directly labeled onto objects or is shown in a

legend. Topological relationships are inferred visually by the map reader. A map sheet can contain

a. single entity type or theme, i.e., thematic map, such as soil map

b. several entity types e.g., topographic maps have contours, rivers, cultural features such

as towns, bridges, etc.


- 29 -

Digital Representation

A map, in the paper form that we are familiar with, cannot exist in the computer. While the human

eye (and brain) is adept at recognizing shapes and inferring spatial relationships among objects,

the computer needs to be instructed specifically how spatial patterns should be recorded, handled

and displayed. The locational, attribute, and topological information inherent in spatial data must

be represented or encoded into the spatial data base. The manner in which the information is

represented is defined by the spatial data base model, there are two main kinds of spatial data

models, i.e., raster and vector models. In simple terms,

a. A raster model tells what occurs everywhere, at each place/cell in the entire study area.

b. A vector model tells where everything occurs, i.e., by giving a location to every object

which one intends to map

Whichever the model, spatial data for a study area are organized into a set of layers

(coverages or themes), each layer may represent a single entity type. However, it is not usual for

distinctly different entity types to be combined in a layer, such as is normally seen in an analog

topographic map. Generally, separation of the complex, realworld features by layers makes spatial

data more easily handled in the GIS. The user cannot "see" the digital spatial data base directly for

it would not make much sense; in order to convert the digital data to comprehensible display would

require certain software commands to retrieve data from the data base and display them on some

output device.

VECTOR DATA STRUCTURE

The Data Model

The objects of a map are defined by tracing its boundaries or locations in relation to a

geographic reference frame. The fundamental primitive is a point, objects are created by

connecting points with straight lines or with splines. The vector data file is therefore a list of points

making up arcs, arcs making up areas, with explicit documentation of membership and topology

and with associated attribute usually kept in a separate file.

RASTER DATA STRUCTURE

The Data Model

Raster model divides the entire study area into a regular grid of cells arranged neatly in

rows. Each cell contains a single value; the value given to a cell depends on the type of entity

being encoded, and the type allowable by the GIS software; it can be:

Precision Farming Terminology

Precision farming is a comprehensive approach to farm management and has the following goals

and outcomes: increased profitability and sustainability, improved product quality, effective and

efficient pest management, energy, water and soil conservation, and surface and ground water

protection.. These terms may be confusing at first, but you will soon become familiar with the

language of PF.


- 30 -

Precision Farming vs. Traditional Agriculture

In PF, the farm field is broken into "management zones" based on soil pH, yield rates, pest

infestation, and other factors that affect crop production. Management decisions are based on the

requirements of each zone and PF tools (e.g. GPS/GIS) are used to control zone inputs. In

contrast, traditional farming methods have used a "whole field" approach where the field is treated

as a homogeneous area. Decisions are based on field averages and inputs are applied uniformly

across a field in traditional farming. The advantage of PF is that management zones with a higher

potential for economic return receive more inputs, if needed, than less productive areas.

Therefore, the maximum economic return can be achieved for each input.

Information, Technology, and Decision Support

PF relies on three main elements: information, technology, and decision support

(management).

Information

Timely and accurate information is the modern farmer's most valuable resource. This

information should include data on crop characteristics, hybrid responses, soil properties, fertility

requirements, weather predictions, weed and pest populations, plant growth responses, harvest

yield, post harvest processing, and marketing projections. Precision farmers must find, analyze,

and use the available information at each step in the crop system. An enormous database is

available on the internet. This data is both accessible and quickly updated.

Technology

Precision farmers must assess how new technologies can be adapted to their operations.

For example, the personal computer (PC) can be used to effectively organize, analyze, and

manage data. Record keeping is easy on a PC and information from past years can be easily

accessed. Computer software including spreadsheets, databases, geographic information systems

(GIS), and other types of application software are readily available and most are easy to use.

Another technology that precision farmers use is the global positioning system (GPS). GPS

allows producers and agricultural consultants to locate specific field positions within a few feet of

accuracy. As a result, numerous observations and measurements can be taken at a specific

position. Global information systems (GIS) can be used to create field maps based on GPS data to

record and assess the impact of farm management decisions. Data sensors used to monitor soil

properties, crop stress, growth conditions, yields, or post harvest processing are either available or

under development. These sensors provide the precision farmer with instant (real-time)

information that can be used to adjust or control operational inputs.

Precision farming uses three general technologies or sets of tools: crop, soil, and

positioning sensors - these include both remote and vehicle-mounted, "on-the-go" sensors that

detect soil texture, soil moisture levels, crop stress, and disease and weed infestations;

Machine controls - these are used to guide field equipment and can vary the rate, mix, and

location of water, seeds, nutrients, or chemical applications;


- 31 -

Computer-based systems - these include GIS maps and databases that use sensor information to

"prescribe" specific machine controls.

Decision support combines traditional management skills with precision farming tools to

help precision farmers make the best management choices or "prescriptions" for their crop

production system Unfortunately, decision support has many times been either unreliable or

difficult to understand. Building databases based on the relationships between input and potential

yields, refining analytical tools, and increasing agronomic knowledge at the local level are yet to be

accomplished. Most agricultural researchers agree that decision support remains the least

developed area of PF. Diagnostic and database development will eventually replace technologies

as the real benefit of PF.

It would be easy to predict the incidence of the plant disease if weather conditions are

recorded properly and an effective data base is prepared for precise decision support. It would be

easier to handle the plant disease if farmers are fore-warned and chemicals are made available in

time to farmers.


- 32 -

Soil Health and Plant Disease Management

B. Mishra Department of Soil Science, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Soil health

Soil health is an assessment of ability of a soil to perform its ecosystem functions as

appropriate to its environment. The term soil health is used to assess the ability of a soil to:

Sustain plant and animal productivity and diversity;

Maintain or enhance water and air quality; and,

Support human health and habitation

The underlying principle in the use of the term “soil health” is that soil is not just a growing

medium; rather it is a living, dynamic and ever-so-subtly changing environment.

Soil quality

The terms ‘soil health’ and ‘soil quality’ are, in a general way, interchangeable. 'Soil quality'

is a term generally used more by soil scientists and 'soil health' by others, but they do have

different emphasis. Both terms link soil to other concepts about health such as environmental

health, human health, plant health, and animal health. ‘Soil health’ and ‘soil quality’ represent the

capacity of soils to support these other aspects of health. So, just as human health is a functional

concept that describes how fit we are to interact with each other and our environment, soil health

and soil quality are functional concepts that describe how fit the soil is to support the multitude of

roles that can be defined for it.

Soil health indicators

The health or quality of soil is rather dynamic and can affect the sustainability and

productivity of land use. It is controlled by chemical, physical, and biological components of a soil

and their interactions. Indicators are the soil properties which reflect the soil health. A short list of

indicators which are suitable for many purposes is given in Table 1. To select a single indicator of

soil health would be of limited use.

Table 1: Soil health indicators used to asses soil function

Indicator Soil function

Visual: crusting, ponding, soil loss Soil degradation, water transmission

Physical: soil aggregate stability, infiltration and bulk density

Retention and mobility of water and nutrients; habitat for macro and micro fauna

Chemical: organic matter, pH, extractable soil nutrients, N-P-K and base captions Ca Mg and K

Soil structure, stability, nutrient retention soil biological and chemical activity thresholds; plant available nutrients and loss of Ca, Mg and K

Biological: microbial biomass C and N; potentially mineralizable N

Microbial catalytic potential and repository for C and N; soil productivity and N supplying potential


- 33 -

Soil conditions that can prevent outbreaks

Pathogens can exist in the soil for long periods of time without causing an outbreak of

disease in plants. Disease outbreaks are either caused by an increase in the population of the

pathogen or by an increase in the susceptibility of the plant. The population of the pathogen is

dependant on whether the soil conditions are favourable for its growth and survival. The conditions

that are favourable for the growth and survival of pathogens are different for each species of

pathogen. The factors affecting the suitability of soil conditions include:

soil pH,

water content,

oxygen level,

nutrient level and

the activities of other soil organisms.

Management practices that restrict the growth of pathogens by producing soil conditions

unfavourable to their growth will reduce the likelihood of disease outbreaks. The susceptibility of

the plant to disease is affected by factors such as its age and nutritional status.

Soil pH

Soil pH plays major roles in disease management. Potatoes are commonly grown in soils

with a pH of 5.0 to 5.2 for control of common scab caused by, S. acidiscabies. Potato scab is more

severe in soils with pH levels above 5.2. Below 5.2 the disease is generally suppressed. Sulfur

and ammonium sources of nitrogen acidify the soil, also reducing the incidence and severity of

potato scab. Liming, on the other hand, increases disease severity. While lowering the pH is an

effective strategy for potato scab, increasing soil pH or calcium levels may be beneficial for

disease management in many other crops.

Recently, management of soybean diseases has been closely linked with soil pH of the

particular field. The severity of brown stem rot of soybean increases as soil pH decreases,

whereas soybean cyst nematode increases as soil pH increases.

Soil fertility and plant health

There is a strong relationship between soil fertility and plant health. Poor soil management

and declining soil fertility often result in a negative feedback cycle characterized in part by an

increase of soil borne diseases. Adequate crop nutrition makes plants more tolerant of or resistant

to disease. Also, the nutrient status of the soil and the use of particular fertilizers and amendments

can have significant impacts on the pathogen's environment.

Adequate nitrogen supply is essential for healthy plant growth but excessive nitrogen

supply makes the plants succulent and susceptible to infection. Presence of adequate phosphorus

imparts resistance to the plant against many diseases. Applied phosphorus has been shown to

allow crops to better tolerate diseases such as take-all root rot fungus and Septoria leaf blotch in

wheat, downy mildew and blue mold in tobacco, Cercospora in soybean seed, and brown stripe

disease in sugarcane. Potassium enhances plant resistance to many diseases such as maize


- 34 -

stalk rot, wheat powdery mildew, rice stalk rot, wheat leaf blight, cotton leaf spot and rapeseed

black spot. Inadequate potash levels can lead to susceptibility to Verticillium wilt in cotton. High

potassium levels also retard Fusarium in tomatoes. Severity of wilt in cotton was decreased by

boosting potassium rates as well.

Adequate levels of calcium can reduce clubroot in crucifer crops (broccoli, cabbage,

turnips, etc.). The disease is inhibited in neutral to slightly alkaline soils (pH 6.7 to 7.2). A direct

correlation between adequate calcium levels, and/or higher pH, and decreasing levels of Fusarium

occurrence has been established for a number of crops, including tomatoes, cotton, melons, and

several ornamentals. Calcium has also been used to control soil-borne diseases caused by

Pythium, such as damping off. Crops where this has proved effective include wheat, peanuts,

peas, soybeans, peppers, sugarbeets, beans, tomatoes, onions, and snapdragons. Researchers

in Hawaii reported reduction of damping off in cucumber after amending the soil with calcium and

adding alfalfa meal to increase the microbial populations.

A more acid soil also fosters better uptake of manganese which stimulates disease

resistance in some plants. Increased plant uptake of manganese decreased take-all disease

(Gaeumannomyces graminis var. tritici), Verticillium wilt in potatoes and stalk rot in maize. Zinc

deficiency is known to cause khaira disease of rice. Silicon , which is not yet an essential element

for plants, has been reported to provide disease resistance in rice.

Disease suppressive soils

Suppressive soils are those in which a specific pathogen does not persist despite favorable

environmental conditions, the pathogen establishes but doesn't cause disease, or disease occurs

but diminishes with continuous monoculture of the same crop species. A classic example is soil

suppressive to the take-all disease of wheat. Disease suppression has been attributed to an

increase in nonpathogenic microorganisms which are well-adapted to growth on wheat roots.

Suppressiveness is linked to the types and numbers of soil organisms, fertility level, and nature of

the soil itself (drainage and texture). The mechanisms by which disease organisms are

suppressed in these soils include induced resistance, direct parasitism (one organism consuming

another), nutrient competition, and direct inhibition through antibiotics secreted by beneficial

organisms.

Suppressive soils have proved to be sources of some important antagonists and they

continue to provide clues useful in developing biocontrol strategies. The existence of soils that are

naturally suppressive to diseases induced by soil borne plant pathogens provides good

opportunities to study situations where biological control is effectively working. In most cases,

suppressiveness is fundamentally based on microbial interactions between the pathogen and

some populations of the saprophytic microflora. However, these biotic interactions are dependent

on the abiotic characteristics of the soil. In the case of soils suppressive to fusarium wilts, it is

obvious that pH and the nature of the clays are important factors interacting with the microbial

populations responsible for suppressiveness. Competition for nutrients, mainly carbon and iron,


- 35 -

has been demonstrated to be one of the mechanisms by which suppressive soils control Fusarium

wilts. Populations of non-pathogenic Fusarium oxysporum and fluorescent Pseudomonas spp. are,

at least partly, responsible for competition for carbon and iron, respectively. Moreover, these

antagonistic populations have other modes of action which can contribute to their biocontrol

activity. Strains of both non-pathogenic F. oxysporum and P. fluorescens are being developed as

biocontrol agents. Studies of suppressive soils suggest biological control could also be achieved

by enhancing the natural level of suppressiveness that exists in every soil.

REFERENCES

1. Datnoff, L.E., Elmer, W.H. and Huber, D.M. (2007) Mineral Nutrition and Plant Diseases, APS Press, Saint Paul, USA.

2. Janvier,C. et al. (2007) Soil health through soil disease suppression: Which strategy from descriptors to indicators? Soil Biol. Biochem. 39 (1): 1-25.


- 36 -

Biotechnological Approaches for Incorporation of Fungal Disease Resistance

Abha Agnihotri

Plant Biotechnology, TERI, Habitat Place, Lodhi Road, New Delhi- 110 003

The changing environmental conditions and the un-predictable temperature fluctuations are

adversely affecting the crop yields; the severity of various diseases has increased and even

evolution of new pathotypes is expected. Utilization of pesticides for controlling the fungal diseases

has serious environmental concerns with respect to environmental degradation and toxicity in non

target species through food chain contamination.

The different strategies adopted to control plant diseases include non-chemical and

chemical control. The non-chemical control includes hot water treatment and biological control.

The chemical control though found to be effective results in development of resistance in the

pathogens and residue toxicity; thereby have a detrimental effect on non-target species. Besides

this, the fungicide sprays affect crop physiology independent of disease occurrence and adversely

affect the quality of the produce. Owing to the above-mentioned problems associated with

chemical control, focus has been to develop new biotechnological techniques for crop protection

and production. Among all the biological approaches available exploiting genetic resistance

present in most eco-friendly and environmentally safe approach.

Selection alone may not help due to non availability of resistant genes within the available

gene- pool/ cultivars. Genes conferring resistance to biotic and/ or abiotic stress are frequently

scattered in weedy and wild species, and can be used for the incorporation of resistance in

cultivated varieties. However the majority of these belong to secondary and tertiary gene pools.

Thus, their exploitation through conventional means is problematic because of the difficulties of

obtaining hybrids and subsequent gene transfer in desirable genetic background due to pre- and

post fertilization barriers.

Pre-fertilization considerations include spatial separation, synchrony of flowering,

pollination system, floral characteristics and competitiveness of pollen whereas post fertilization

considerations include genetic/sexual compatibility, hybrid viability, and fertility of progeny and

successful introgression. For successful gene introgression all pre- and post fertilization

requirement must be met, failure to meet anyone requirement will render to non-introgression of

the gene, thus would not produce the desirable results. Therefore inter-specific and/ or inter-

generic sexual hybridization through wide hybridization utilizing in vitro techniques, somatic

hybridization and genetic engineering are the approaches that can be used to enhance the scope

and efficiency of transfer of disease resistance traits across genera and species barriers.

Wide hybridization has been used to transfer disease resistance traits as well as various

economically important agro- morphological traits. Laibach for the first time reported embryo

rescue in 1925, since then it has been efficiently to develop hybrids and to transfer economically


- 37 -

important traits. The production rate of hybrids can be markedly increased by improving the culture

media composition and by several modified culture techniques indicating that the embryo abortion

is due to non-development of the ovule or the endosperm even though the embryo remains

healthy. Ovary culture along with sequential embryo rescue culture has been reported to be more

successful than ovule culture to produce wide hybrids in the crucifers. Fusion of protoplasts at the

level of plasma membrane is non-specific, and there is no barrier to inter-specific, inter-generic or

even intertribal fusion of cells.

Somaclones are the naturally occurring variations in tissues cultured in vitro, and are

utilized for genetic variability generation and selection for desired traits. The mutagenesis is also

known to create novel genetic recombinants. When the multi-cellular tissues are treated with

mutagens a chimeric structure is expected necessitating the examination of a large population and

additional efforts for generation of homozygous lines. These limitations can be overcome to a large

extent by combining mutagenic treatment with doubled haploid production. The doubled haploids

can be generated either by androgenesis or through microspore embryogenesis. Out of the two,

microspore embryogenesis is preferred as it eliminates the interaction of other tissues and single

cell mutations are true to type. The most important application of microspore culture is the production

of instant homozygous plants in a single step, with novel genotypic combinations in a single

generation. Therefore, the doubled haploids have been profitably utilized for mutation breeding for

generating novel genetic recombinants for disease resistance.

Apart from such widely accepted biotechnological approaches, genetic transformation and

marker aided selection, has also been effectively utilized for incorporation of fungal diseases/

selection of breeding populations with resistance/ high tolerance. Molecular markers that are

tightly linked to the trait of interest, besides, helping in identifying the desired plant species at any

growth stage of the plant and reducing the time also helps to select for the trait under strict

quarantine laws. However, even then the crop plants have to be tested for virulence against the

pathogen to confirm the effectiveness of the marker associated with the resistant gene. Marker

assisted selection or MAS as it is commonly known has been successfully utilized in identifying

economically important traits in many crop plants such as maize, tomato, tobacco, rice, wheat, and

brassicas to name a few. The transgenic technology has a great potential in this direction,

however, the availability of the desired genes governing adequate resistance, and an efficient

regeneration system from somatic explants is a pre requisite for its appropriate application. The

various biotechnological approaches with case study and the relevant bio-safety issues will be

discussed.

REFERENCES

1. Agnihotri A (1993). Hybrid embryo rescue. In: Plant tissue culture manual: fundamentals and applications (Ed) Lindsey K, E4: 1-8. Kluwer Academic Publishers, Dordrecht.

2. Bansal VK, Thiagarajah MR, Stringam GR, Tewari JP (1999). Inheritance of partial resistance to race 2 of Albugo candida in canola-quality mustard (Brassica juncea) and its role in resistance breeding. Plant Pathol 48(6): 817-822.


- 38 -

3. Cheung WY, Gugel RK, Landry BS (1998). Identification of RFLP markers linked to the white rust resistance gene (Acr) in mustard (Brassica juncea (L.) Czern. And Coss.). Genome 41(4): 626-628.

4. Deepak Prem, Kadambari Gupta, Gautam Sarkar and Abha Agnihotri 2008. Activated Charcoal induced high frequency microspore embryogenesis and efficient doubled haploid production in Brassica juncea Plant Cell Tissue & Organ Culture, (DOI 10.1007/s 11240-008-9373-1)

5. Duncan S, Barton JE, O’Brien PA (1993). Analysis of variation in isolates of Rhizoctonia solani by random amplified polymorphic DNA assay. Mycol Res 97: 1075-1082.

6. Ferreira ME, Williams PH, Osborn TC (1995). Mapping of a locus controlling resistance to Albugo candida in Brassica napus using molecular markers. Phytopathol 85(2): 218-220.

7. Gupta K, Prem D, Negi M S and Agnihotri A 2004. ISSR’s: An efficient tool to characterize interspecific F1 hybrids of Brassica species. In: 4

th International Crop Science

Congress, Sept. 26-Oct. 1, 2004, Queensland, Australia.http://www.regional.org.au/au/cs/2004/poster /3/4/4/1974_agnihotria.htm

8. Gupta K, Prem D, and Agnihotri A 2003. Role of biotechnology for incorporating white rust resistance in Brassica species. In: Plant Biotechnology and Molecular Markers, (eds) P S Srivastava, A Narula, and S Srivastava, Kluwer Academic Publishers, Dordrecht, Netherlands and Anamaya Publishers, New Delhi, pp. 156–168

9. Kadambari Gupta, Deepak Prem, Nash Nashaat and Abha Agnihotri.2006 Response of interspecific Brassica juncea x Brassica rapa hybrids and their advanced progenies to Albugo candida (Pers.) Kunze. Plant Pathology 55: 679-689

10. Khush GS, Brar DS (1992). Overcoming barriers in hybridization. In: Distant hybridization of crop plants.(eds) Kallo G, Chowdhary JB, Springer-Verlag Heidelberg, 47-62.

11. Kolte SJ, Awasthi RP, Vishwanath (1994). Divya mustard: a unique plant type and its developmental traits in disease management. Cruciferae- Newslett 16:128-129.

12. Kolte SJ, Bardoloi DK, Awasthi RP (1991). The search for resistance to major diseases of rapeseed mustard in India. In: GCIRC 8

th Int Rapeseed Congress, July 9-11,

Saskatoon, Canada, 1: 219-225.

13. Mora, A.A. and E.D. Earle. 2004. Resistance to Alternaria brassicicola in transgenic broccoli expressing a Trichoderma harzianum endochitinase gene. Molecular Breeding 8: 1-9

14. Prabhu, K.V., Somers, D.J., Rakow, G. and Gugel, R.K. 1998. Molecular markers linked to white rust resistance in mustard Brassica juncea. Theoretical and Applied Genetics. 97: 865-870

15. Quiros CF, HU J, Truco MJ (1994). DNA-based marker maps of Brassica. In. Philipps RL and Vasil IK (Eds) DNA based markers in plants. Kluwer Academic Pub. Dordrecht 11 : 199-222.

16. Sheikh IA, Singh JN (2000). Genetics of resistance to White rust in Indian mustard [ Brassica juncea (l.) Czern & Coss]. Crop Research 21 (3): 341-344.

17. Rene Grison, Bruno, G.B.; Michel, S.; Nicole, L. 1996. Field tolerance to fungal pathogens of Brassica napus constitutively expressing a chimeric chitinase gene NatureBiotechnology 14: 643-646

18. Singh D, Singh H (1987). Genetic analysis of resistance to White rust in Indian mustard.In: 7th International Rapeseed Congress , Pozman, Poland, 11-14 May, 1987. Pp 126.

19. Tewari AS, Petric GA, and Downey RK (1988). Inheritance of resistance to A.candida race 2 in mustard ( B.juncea (L.) Czern). Can J Plant Sci , 68 : 297-300.

20. Varshney, A., Mohapatra, T., Sharma, R. P. 2004. Development and validation of CAPS and AFLP markers for white rust resistance gene in Brassica juncea. Theor Appl Genet 109:153-159


- 39 -

Recent Advances in Integrated Management of Vegetable Diseases

S.N. Vishwakama Department of Plant Pathology, GBPUA&T, Pantnagar- 263145(Uttarakhand)

Vegetable are important source of dietary, minerals and vitamins. All the developed

and developing countries realize the importance of vegetables as an essential diet due to

medicinal and nutritional value for human health. There is steady upward trend in vegetable

production. China is ranking first in world and currently produces 237 million tons of

vegetables. India has a quantum jump in vegetable production securing the second positions

in the world. The total production of vegetable is more than 91 million tons in the country. In

spite of this, the productivity of vegetable per unit area is very low. Thus the produces at

present is approximately half of the requirement as per dietary standard against 250-300 gms

/day/adult. Vegetable being more succulent and rich in nutrient are more prone to disease

infection, therby incurring high yield losses during pre and post production period. Disease

pressure in vegetable crop from seedling stage to harvest caused by mainly fungi, bacteria

and virus are the most important constraints for low production.

Management of vegetable diseases-An over view:

The survey of literature reveals that vegetables either grown directly or through

transplanted seedling suffer from a variety of biotic, mesobiotic and abiotic causes. Control

methods invariably recommended includes cultural practices, host resistance, chemical

control, physical and biological control methods. Individually different methods have been

recommended for management of different disease, but among the recommendation

application of pesticides is really high and thereby posing problems of residue poisoning, pest

resistance and economic. Under this situation application of integrated disease management

(IDM) appears most appropriate as production is to increase and harmful effect of pesticide is

to decrease.

Integrated disease management (IDM):

The philosophy, principles and objective of IDM state that “A desirable approach to the

selection, integration and use of methods on the basis of their anticipated economic,

ecological and sociological consequences”. Under the concept of disease management

reduction in losses cause to vegetable must take into account that following criteria for

developing IDM schedules:

Develop the schedule which is economical. The cost of application and loss due to

disease must be proportionately balanced in favour of producers.

The schedule development fit in the production protection schedules practiced by the

growers.

The schedules developed must strive to manage most pest and disease

simultaneously in the crop concerned.


- 40 -

To ensure success the IDM schedule in the vegetables need to be applied as

community programme and /or cooperative programme.

Management of vegetable diseases: The existing technology:

Based on nature of vegetable diseases, the control strategies could be prophylactic or host

resistance. The principle of prophylaxis could be achieved by applying the principle of exclusion,

eradication and protection. To achieve exclusion method such as quarantine, inspection and

certification and seed treatment have been recommended. In order to achievement the eradication

of inoculum methods like biological control, crop rotation, rouging crop refuse destruction,

sanitation, including distruction of collateral and alternate hosts have been recommended.

In protection, those practice which function as a barrier between host and pathogens (no

contact). The practices are cultural practices such as methods of planting, time of

sowing/transplanting, balanced fertilizer, controlled irrigation, spray of micro nutrients and

application of pesticides, fungicides, antibiotics, nematicide etc. are recommended.

Principally, the use of resistant genotype looks the best method for diseases management.

The methods used to develop resistant genotype are introduction, selection, hybridization, mutation,

biotechnological and molecular technique. Development and use of resistant genotype is

continuous and never ending process due to evaluation of new biotype/pathotype/races. The

resistant is broken down as a matter of fact development of resistant to disease in vegetable is yet

to get place and recognition given to place cereals and pulses.

Guide lines for developing IDM:

Vegetables are different from cereals because cereals are harvested only once after sowing

therefore enough time is available to apply management strategies. On the other hand most

vegetables are harvested several times at different stages of the crop growth and therefore

the application of control method particularly fungicide suffer due to shortage of time, also

for consideration of safe period.

Vegetable are raised repeatedly following the principles of intensive farming. This practices

favour survival of primary inoculum and subsequently infection and spread of secondary

inoculum in the crops. To ensure success of any IDM schedule the impact and the effect of

intensive cultivation on diseases must be the major input in developing the schedule.

The vegetable in India is still today are grown on small scale. Cucurbits and beans are

grown ever around the house and the such crops are reserviour of inoculum of number of

pathogens as no control measure is invariably applied. This major sources of inoculum must

also be considered for developing the schedule.

The schedule develop must be easy approachable and effective to be used at community or

co-operative level.

Development of IDM schedule for diseases of brinjal-An example:

Brinjal suffers due to disease caused by Fungi, Bacteria, Viruses, Phytoplasma and


- 41 -

Nematodes. However, among the disease, damping-off (in nursery), Alternaria leaf spot,

Cercospora leaf spot, Phomopsis blight and fruit rot, Sclerotinia blight and fruit rot, Bacterial wilt and

Root-knot are the most important ones. The primary inoculum of the diseases listed above survives

either in/on seed or soil as resting structures or the infected crop debris as facultative saprophyte.

The secondary inoculums produced after infection, disseminate through the agency of air, water,

insect and during intercultural operations and therefore schedule development must attack initial as

well as secondary inoculums.

The schedule

i. Raised nursery, on raised solarized bed and the maintain plant density and soil moisture.

ii. Avoid frequent irrigations and heavy nitrogen application.

iii. Use healthy and certified seeds.

iv. Treat seed by physical and chemical means using heat or fungicide. Among fungicide,

thiram, captan@ 0.25%, Carbendazim @ 0.1%, Apron @ 0.4%.

v. Destruction of crop debris, deep summer ploughing, organic amendment, crop rotation, date

of sowing/transplanting to be used as per recommendation.

vi. While transplanting root treatment either with fungicide or bio-agent.

vii. Application of nematicide /fungicide/ for the control of inoculum existing in soil.

viii. Foliar application of required pesticides.

ix. Use of resistant/to tolerant varieties/ cultivars.

REFERENCES

1. Chaube, H.S and Ramji Singh, 2001. Introductory Plant Pathology JBD Co. Lucknow 360 pp.

2. Singh, R.S. 1984. Introduction to Principles of Plant Pathology Oxford & 1BH Publishing Co. New Delhi. 534 pp.

3. Singh, R.S. 1984 Disease of Vegetable Crops Oxford & IBH Publishing Co. New Delhi.346pp.


- 42 -

Managing disease through host resistance

D. Roy Department of Genetic and Plant Breeding, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Resistance is a trait which appears as a result of pathogen x host x environment

interaction. Disease can be controlled by controlling any one factor or a combination any two or

three factors. Pathogens could be fungi, bacteria, viruses or nematodes. Pathogen can be

avirulent or virulent. Further pathogen can show a degree of pathogenicity. Similarly, host can

show resistance or susceptibility. Host can also show a degree of resistance ranging from

immunity to high susceptibility. Finally, environment can be favourable or unfavourable. A virulent

pathogen in combination with susceptible host in favourable environment can produce lots of

disease. The disease control measures thus include the following:

1. Sanitation

2. Cultural practices

3. Chemical control

4. Biological control

5. Use of resistant variety

Before embarking on use of resistance one will have to work out the genetics of resistance-

whether the resistance is qualitative or quantitative. How many genes are determining resistance

against a particular pathogen? What type of gene action and interaction is there; whether the

inheritance is nuclear or extranuclear. Similarly one should know what is simple race and complex

race. Further one will have to understand the mechanisms of resistance against fungal, bacterial,

viral or nematode. One can control the disease by using either race-specific resistance gene or

race non-specific resistance gene or tolerance. The race-specific resistance gene can be used in

the following ways.

1. Singly

2. Deployment

3. Pyramiding of genes

4. Multine/mixture

In the first method of control one gene can be used at a time which will ultimately result in

Boom-bust cycle. This strategy exerts strongest selection pressure on pathogen and the selection

is termed directional selection. The boom-bust cycle can be broken by the following:

1. Localized use of R-gene

2. Cycling of R-gene

3. Polygenic resistance

4. Combination of VR and HR

5. Multigene variety/pyramiding of genes

6. Multiline/mixture


- 43 -

Gene deployment is effective against pathogens which migrate over long distance whereas

use of single gene is effective against localized pathogens. Gene deployment can be spatial or

temporal. Gene deployment strategy use a set of R-genes. The examples of disease control

through gene deployment include Puccinea path in crown rust in oat and in stem rust of wheat.

Gene deployment exerts a type of selection called disruptive selection

The principle underlying this method of control is to use a variety with a specific VR gene at

place where the epidemic ends and put a variety without this VR gene at the start of epidemic.

Pyramiding of genes refers to stacking of genes in a variety. In other words, the variety

contains multigenes for resistance. Here a variety contains 4-5 resistance genes which could give

stable resistance for centuries. There are also examples of multiple resistance in which one gene

for resistance against one disease could give resistance against other diseases. The one can use

combined resistance(VR + HR) for controlling disease. In this strategy one will have to first select

an F3 family with VR gene and then one should screen the different members of the family for

VR+HR. While breeding for combined resistance one should keep in mind the ‘vertifolia effect’.

Development of multiline variety involves two approaches- clean crop and dirty crop approaches.

8-16 component lines can be used for developing multiline variety. While using mixtures for

managing disease one should consider the following:

1. Composition of mixture

2. Number of components

3. Changing the crop density

4. Mixing the fields.

Further, varieties constituting the mixture can be from the same crop or from the different crops.

Besides all strategies mentioned above, one can use race-nonspecific resistance and tolerance for

managing disease. The reader is referred to Roy(2000) for detail.

REFERENCE

1. Roy, D.(2000). Plant Breeding-Analysis and Exploitation of Variation. Narosa, New Delhi.


- 44 -

Recent Advances in Management of Wilt and Root Rot Complexes of Chickpea (Cicer Arietinum L.)

H.S. Tripathi and Santosh Kumar

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand) Chickpea (Cicer arietium L.) is a major grain legume crop in Asia, Africa, and America with

a world cultivated area of 11.5 million hectare, production 8.88 million tones and productivity 797

kg/ha, is infected by 172 pathogens, Among theses wilt (Fusarium oxysporum f.sp. ciceri). Collar

rot (Sclerotium rolfsii), wet root rot (Rhizoctania solani, dry root rot (R. bataticola) are important

diseases. It is a soil- borne disease. These diseases are reported from 54 countries including India

(Nene et al,; 1996). All types of chickpea is infected by this disease. In India, chickpea is cultivated

in 7.22 million ha. with annual production 6.01 mt. and productivity 855 kg/ha (Anonymous 1998)

which is pretty low in comparison to Australia (1335 kg/ha) and Maxico (1470 kg/ha). The yield

losses vary between 10% and 100%, depending upon the agro climatic conditions (Jalali &

Hanichand, 1992).

Symptoms

The disease occurs at two stages of plant growth (i) seedling stage and (ii) flowering stage

or adult stage. The fungus infects the root system by penetrating the epidermis, cortex and finding

its way into xylem vessels where it colonizes extensively, producing conidia. The pathogen then

grows upward in the shoot, and extensive growth of the pathogen in vascular bundles plunges

them. Other symptoms includes yellowing and drying of leaves from base upward, dropping of

petioles and rachis, improper branching, withering of plants, browning of vascular bundles and

finely wilting of plants when disease occurs at seedling stage the seedling collapse and lies flat on

the ground surface, although they retain normal green colour. Such seedlings when uprooted

generally show uneven shrinking of the stem above and below the collar region. Area near the

collar region downward, black discoloration of xylem vessels is visible. Some times only a few

branches are affected which result in partial wilting.

Causal organism

Chickpea wilt is caused by Fusarium oxysporum Schlech. Snyd. and Hans. f.sp. ciceri

(Padwick) Snyd. & Hans. F. oxy. sp. ciceri (Padwick) Snyd. & Hans. The existence of 5 races

among India isolates has been demonstrated. Root rot complex includes, collar rot (Sclerotium

rolfsii) wet root rot (Rhizoctonia solani) dry root rot (R. bataticola, Telemorph-Macrophomina

phaseoli) damping off- Pythium and Phytophthora spp.).

Epidemiology

The wilt fungus may be seed-borne and may survive in plant debris. Fungus remains in the

hilum of the seed in the form of chlamydospore like bodies. Haware et al. (1978). The primary

infection is mainly through chlamydospores or mycelia. The conidia of the fungus are short lived;

however, the chlamydospores can remain viable up to next season collar rot and root rot


- 45 -

pathogens survive in the form of sclerotia. The pathogen survives in infected roots and stems.

Plant spp. other than chickpea may serve as symptom less carriers of the disease viz., Pigeon

pea, Lentil and Peas. The pathogen may also parasitize several weeds such as Cyperus rotundus,

Tribulus lerrestris, Convolulus arravis and Cardiospermum lalica cabum (Haware & Nene 1982).

Root pathogens infect several plant species. The soil type, reaction, moisture and temperature are

known to influence disease development. The disease is more severe in light sandy soil than

heavy clay ones (Kotasthane et al. 1979). Chauhan (1962) noted that the disease intensity

increased with lowering pH. alkaline soils favors incidence of wilt Shaika (1974) reported that the

pathogen tolerated a wide range of pH, with optimum between 5.0-6.5. High soil temperature and

deficiency of moisture appear to have a definite bearing on the incidence of the disease. Soil

temperature relations showed that the disease is optimum at 25°C and is at a lower at 20°C. The

amount of organic matter and humus content of the soil were found inversely related to wilt

incidence Chauhan (1962).

Disease Management

Chemical seed treatment

Seed treatment with Bavistin or corboxin (0.25%) improved seed germination by 16.5%

greatly reduced wilt incidence and increased yield by 23.7%. Seed inoculation with Rhizobium

followed by seed treatment with Bavistin (0.1%) is more effective in reducing wilt, increasing

nodules/plant and yield than Bavistin (0.1%) alone. Seed treatment with Bavistin + thiram (0.5+2.0

g/kg seed) has also been found promising. Rovral (0.2%), Mildothan (0.1%), Brassicol (0.2%) and

Dithane M-45 (0.2%) treatments enhanced seed germination and/or seedling vigour (Chaube et

al., 1984). Seed treatment with grarlic leaf extract and neem oil are also reported to produce

disease free seedlings.

Biological control

Suppression of wilt has been observed in potted plants following soil inoculation with

vesicular-arbuscular mycorrhizal (VAM) fungus. The endophyte colonized plant roots extensively

which resulted in reduction in wilt incidence form 80% in non mycorrhizal to 26.6% in mycorrhizal

plants. In such plants phosphate uptake efficiency was also significantly enhanced. Use of

Trichoderma viride, Gliocladium virens and Bacillus subtilis has been found effective and eco-

friendly for the control of wilt & root-rot complexes.

Cultural control

Early sown crop usually attract more disease while in late sown November planting low wilt

incidence is observed. The lower disease incidence in late sown crop was considered to be due to

low temperature prevailing during the period of late sown crop. Plants spaced at 15-20 cm had

much higher disease incidence than those spaced at 7.5 cm. Planting of seeds at proper depth

(10-12cm) is helpful in reducing disease incidence, while shallow sown crop seems to attract more

disease. Planting the crop with 'pora' method using lower seed rates helps to minimize disease

whereas broadcast method of planting increased wilt incidence. More incidence of wilt is recorded


- 46 -

under moisture stress conditions. Mixed cropping with wheat and berseem results low incidence of

wilt & root rots.

Varietal resistance

Cultivation of wilt resistant cultivars seems to be the best method for the control of wilt

although other conventional chemical and cultural methods have not found wide adoption. Many

resistant varieties have been developed under All India Corrdinated Pulses Improvement Project

(I.C.A.R.) viz; G-24, PG-114, Avarodhi, Hartyana Channa-2, PC-1, WR-315, BG-256, Uday, Phule

G-1, RSG-2.

REFERENCES

1. Anonymous (1998). Project Coordinator Report-All India Coordinated Research Project on Improvement of Chickpea (I.C.A.R.) I.I.P.R., Kanpur.

2. Chaube, H.S.; Rathi Y.P.S. and Tripathi, H.S.(1984). Search for effective seed dressing fungicides to control wilt complex of chickpea (Cicer arietinum L.). Seeds and Farms IX (4): 23-25.

3. Chauhan, S.K. (1962). Influence of pH in sand culture on disease intensity and crop loss correlation in Fusarium wilt of gram. J. Indian Bot. Soc.41:220.

4. Chauhan., S.K.(1962). Fusarium wilts of gram in relation to organic matter of soil. Vigyana Parishad Anusandhan Patrika, 5: 73.

5. Haware, M.P.,Nene, Y.L. and Raje Shwari: R.(1978).Eradication of Fusarium oxysporum f.sp. ciceri transmitted in chickpea seeds. Phytopathology 68: 1364.

6. Jalali, B.L. and Harichand (1997).Chickpea wilt. Plant Diseases of International Importance Volume I (eds.) U.S.Singh et al. prentice Hall. New Jersey.

7. Kotasthane, S. R. Agarwal, P.S., Joshi, L.K. and Singh, L.(1979).Studies on wilt complex of Bengal gram. JNKVV Res. J. 10:257.

8. Nene, Y.L.; Sheila, V.K. and Sharma, B.B.(1996).A world list of chickpea and pigeon pea pathogens. Fifth edition ICRISAT, Pathancheru 502 324

9. Shaika, M.H.(1974). Studies on wilt of gram in Marathwada region M.Sc. (Ag.) thesis MKV Prabhani ( India).


- 47 -

Micro-Meteorology in Relation to Plant Disease Development

H.S. Kushwaha Department of Soil Science, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Introduction

Microclimate of crop refers to the weather conditions within or near the crop canopy and

depends upon the physicals processes taking place in the air layer near the ground. Air

temperature within crop canopies changes and depends upon canopy structure, height of crop,

time of the day, cloud cover etc. Canopy structure is a function of cultural practices, type of crop

and varieties. Plant row width and soil fertility can also change the microclimate. Initiation and

progress of plant diseases is the outcome of interaction of four vital elements viz. Host

(susceptibility), Pathogen (Virulence), Environment (Favourable) and time (Duration of

interaction). These four elements form the " Disease Pyramid " and if these arms representing

four elements can be measured / quantified, the volume of Pyramid will be a measure of

disease produced. All these four elements are vital, but the role of environment become more

important as it influences both host as well as the Pathogen. The severity and the extent of this

interaction is markedly affected by the environment and the element of time. Not only the growth

of the host is affected by weather elements such as maximum & minimum temperatures,

relative humidity, wind speed & direction, rainfall, solar radiation, sunshine hours, soil

temperature, dew, fog, frost etc., but they have also a profound influence on Pathogen and

disease development. The amount of primary inoculums present is important for subsequent

disease development. The climatic conditions significantly influence dormancy of plant pathogens

and therefore, the plant inoculums, when growth commences. Apart from biological factors, the

micro-meteorological factors such as duration of leaf wetness, leaf temperature, duration and

intensity of rain, wind speed and its direction & relative humidity within and above the crop

canopy play a very important role in release and dispersal of the pathogens. The plant surface is

linked to the environment through the flow of energy between them. Humidity conditions and

specially dew affects the growth and development of many phyto-pathogens, especially the fungal

organisms. The temperature of the surface is the equilibrium temperature at which the sensible

and latent heat fluxes from the surface equal the net gain by radiation. Leaf temperature is,

therefore, sensitive to any changes or differnces in the levels of exchange. Each leaf or part of a

leaf has its own equlibrium level and in this way has a unique microclimate responsible for disease

outbreaks.

Weather can be defined as physical state of atmosphere at a particular location at a given

time and it is highly dynamic phenomenon. On the other hand the climate can be defined as a

long term (at least 30 years) average / aggregate weather of a locality The process of disease

development is greatly influenced by the weather changes in the close vicinity of Host-Pathogen

interaction. Thus a measurement of climatic variables gives real insight in the Host - Pathogen


- 48 -

interaction and it is the outcome (i.e. The Plant Disease). Since the management plant diseases

are mainly governed by the day today variations in both macro- as well as micro- weather

variables, it is, therefore, essential to monitor these variables using suitable meteorological

instruments.

2. Macro - & Micro - Meteorological Variables for Disease Development

The major macro and micro-meteorological variables which are important from the point of

view of disease development are maximum and minimum temperatures ; relative humidity ; wind

speed and its direction ; rainfall, dew ; intensity and duration of solar radiation ; duration of leaf

wetness etc.. It is also important to distinguish between macro-climate (meteorological screen) and

microclimate (climate at or very near to the host surface, canopy). Micro-climate affects growth

and development of diseases to the extent to which it causes changes in the microclimate. Rain is

a macroclimatic factor and the continuous drizzle or occurrence of dry and wet spells influence

some diseases. Dew is a microclimatic factor and when the relative humidity increases above 70

% condensation begins on plants. Micro-climatic factors influence plant diseases more than

macro-climatic factors.

Keeping in view the importance of meteorological variables, it is essential to measure them

accurately by correct meteorological instruments. In the present lecture efforts have been made to

explain in brief the ways and means of measurement of important meteorological weather

variables especially in the meteorological observatory & the micro - meteorological variables in

relation with disease development. The micrometeorological weather variables are monitored by

Automatic Weather Stations which are being installed in the cropped fields for specific research

purpose.

A) Macro - meteorological variables

The major macro-meteorological variables are measured in the meteorological

observatories which are situated all over the country almost in all State Agricultural Universities,

ICAR Institutes and also by India Meteorological Department

A plain area of 55 m (N-W) x 36 m (E-W) size with short cut grasses provides a good exposure

for all the meteorological instruments in the observatory. If a person stands at the gate facing the

observatory plot, he will find the tall instruments in the back row and shorter instruments in the

front rows. In general the instruments are separated at a distance of 9 m from each within rows of

12 m apart. The method of measurement of the important meteorological variables is described

under the following sub-heads:-

1). Maximum and minimum temperatures

The maximum and minimum air temperatures (oC) are measured by maximum and

minimum thermometers, respectively. They are housed in a single stevension in approximate

horizontal position at about 4 feet height from the ground. The screen is errected on 4 wooden

posts supplied with the screen with its door opening to the north and the bottom at 4 feet

approximately above the ground level.


- 49 -

2). Relative Humidity

The relative humidity (%) is measured indirecely by the readings of dry and wet bulb

temperatures. The dry and wet bulb temperatures are measured by Dry and wet bulb

thermometers wich are placed in the above Stevenson screen perfectly in the vertical positions.

The height of the bulbs of dry and wet thermometers should be from 4' 3" to 4' 6" above the

ground, respectively for correct measurements. From the readings of dry and wet bulb

temperatures the relative humidity is computed using Hygrometric Tables prepared by India

Meteorological Department (IMD), Pune, based on the values of Atmospheric Pressure of the

observatory locations throught the Country. At Pantnagar the Hygrometric Table of 1000 mb is

used.

3). Soil Temperature

The soil temperatures (oC) in the observatory are measured by specially designed Soil

Thermometers at 5, 10 and 15 cm soil depths. The plot where these thermometers are exposed

should not receive any shadow from the neighboring instruments or objects. The bulbs should be

at a vertical depth of 5 cm, 10 cm and 20 cm below the soil surface and the slant of the stem of the

thermometer should be towards north, i.e. the observer should be able to read the instruments by

sitting to the south of the instruments.

4). Rainfall

The rainfall is measured by Raingauge. The ordinary raingauge is errected on a masonry

or concrete foundation of 3' x 3' x 3' size and sunk into the ground. Into this foundation the base of

the gauge is cemented so that the rim of the raingauge is exactly one foot above the ground level

and 10" above the concrete structure, i.e. the concret structure will project 2" above the ground

surface. While getting the gauge, great care is taken to ensure that the rim is perfectly level.

However, the continuous recording of rainfall in the observatory is done by Self Recording Rain

Gauge on Charts.

5). Bright Sunshine Hours

The recording of the number of bright sunshine hours (hrs) is done by Campbell Stoke's type

Sunshine Recorder. This instrument is exposed on the terrace of the roof or on a pillor in the 'open'

where the horizon is clearly visible between North - East and South - East on the Eastern side and

between North - West and South - West on the Western side. The instrument should be placed on a

solid masonry pillor of any suitable height of 5' or 10' above ground depending upon the exposure on

eastern and western sides and rigidly fixed to it after proper adjustment is made. The number of burns

on the sunshine cards are counted to compute the duration of bright sunshine hours (hrs) in a day on

daily basis. However, no burning on cards takes place on cloudy days.

6). Solar Radiation

The quantity and intensity of solar radiation is measured by Pyranometer. This instrument

is placed in the same way as the sunshine recorder. The output in terms of solar radiation is

expressed in W m-2 or Cal.cm-2 day-1 units.


- 50 -

7). Wind Speed and Wind Direction

Wind speed (km hr-1) is measured by Anemometer while its direction (in terms of Compass

points) is measured by Wind vane. These wind instruments are errected at a height of 10 feet from

the ground on wooden posts. The site for these instruments must be as open as possible and

there must not be any object loftier than the instrument for a long distance (as far as possible)

around. Long trees and building in the neighborhood are always objectionable. Even if there are

not lofty enough to screen the instruments, they serve to cause eddies or swirls which act on the

windvane from a direction different from that of a general air current in the neighborhood.

Such obstructions do not also allow winds from all directions to strike the anemometer cups with

equal force. The standard exposure of wind instruments over open level ground in the observatory

plot should be 10 ft. above the ground. The distance between the wind instruments and any

obstruction should be at least 10 times the height of the obstruction.

8). Dew

Dew (mm) is measured by Dew Gauges which are exposed at four heights on a stand and

the appearence of dew drops is compared with the standard photographs to quantify the dew in

terms of mm of dew fall on daily basis.

9). Recording Instruments

i). Air Temperature:

The continuous recording of air temperature (oC) is done by the Thermograph or Thermo-

hygrograph. They are placed in the observatory area inside the double Stevenson screen. In the

same screen, a standard thermometer is also placed for comparison with its bulb at the level of the

thermal element and at a horizontal distance of about 5" from it.

ii). Relative Humidity:

The continuous recording of the relative humidity (%) of free air in the observatory is done by

Hair Hygrograph or Thermo-hygrograph. They are exposed in the observatory in the same above

double Stevenson screen. The Stevenson screen should be located in a place where the surrounding

air is not polluted by excessive smoke or dust particles or is surcharged with brine or oil vapour, since

these instruments have a deleterious effect upon the hygroscopic properties of the hair.

B) Automatic recordings of micro-meteorological variables:

The continuous recording of micro-meteorological weather parameters is done by

Automatic Weather Stations and they are installed in the cropped fields to monitor the

microclimate of crops. The automatic weather station is composed with various

micrometeorological instruments for monitoring of micrometeorological weather variables such as

Air temperature (oC), Relative humidity (%), Wind speed (m s-1), Wind direction (degrees from

North), Leaf temperature (oC), Leaf wetness (% of total wet), Solar radiation (W m-2), Net radiation

W m-2), Rainfall (mm) and Soil temperature (oC).

3. Micro-meteorological variables for crop disease development :

There is a close relationship between plant diseases and the weather variables. The viral


- 51 -

and bacterial diseases are more weather-depended due to the fact that viral and bacterial

pathogens remain at fixed locations, consistently exposed to a particular type of weather for a

sufficiently long period. Some of the examples of disease-weather relationships are given below:

1. High air temperatures may set limits to the development of plant disease. A high temperature of

> 35 (oC) is fungicidal to the organism causing blister blight in tea. A temperature of > 25 oC

prevents spore formation in "phytophthora infestanis", the late blight fungus. Relatively high

temperatures are important for the rate of inoculums build up of downy mildews. In potato

blight, temperatures near the optimum for vegetative mycelial growth (19 -22 oC) stimulate the

development of blight within the potato leaves, thus favouring spread by conidia produced

by the leaves.

2. Soil temperature play an important role in management of various diseases specially the soil as

well as the seed born diseases. Heating of soil by solar radiation can be managed by using the

mulches. Killing of fungal spores may be higher under high soil temperature conditions

compared to low temperatures. Generally the soil temperature data is recorded during 0700

and 1400 hours of the day and an average value is calculated. But it did not give the clear

picture of periodic soil temperature variations under mulch and non mulch conditions. For

example the effect of soil solarization on soil temperature regimes studied through AWS at

Pantnagar showed that degree day accumulation varied from 919 (38.3 oC) to 787 (32.8 oC)

degrees under plastic mulch and non-mulch, respectively, in a single day at Pantnagar.

3. Microclimatic humidity is of importance for fungal plant diseases, and not the macroclimatic

humidity as registered in meteorological screens. Further, disease is more affected by

microclimatic conditions in the plant canopy than by the macroclimatic ones as measured at

the standard meteorological stations / observatory located at more distance from the crop field.

4. The duration of leaf wetness (LWP) is important in the development of plant diseases. The

germination and substantial crop infection by "phyphthora infestanis" requires a minimum LWP

of 13 hours. The LWP for infection by several pathogens varies from 0.5 hours to more than

100 hours. The accomplishment of substantial infection by "Venturia inaequalis ", the fungus

causing scab on apples and pears, require a period of wet leaves the minimum duration of

which is linked to the temperature error. Duration of precipitation and the persistence of fog are

of prime significance in LWP. Typically the infection process on wet leaves proceeds more

quickly at high temperatures, so that temperature during the wetting period as well as the LWP

must be considered. Different combinations of LWP and temperatures are important for

development of different diseases. Often the two factors are combined to construct an index

for the occurrence of a plant disease of interest.

5. Mather (1974), reported that in United States, the bacterial wilt and leaf blight in corn is related

to the previous inter conditions. When the sum of the average temperatures of December,

January and February remains below 38 oC, there is no chance of wilt on corn. If the sum of

the average temperatures is above 29.5 oC, corn blight is likely to occur. This follows that if the


- 52 -

winters are mild, the bacterial wilt and leaf blight are likely to spread in an epidemic form in the

coming crop while severe winters reduce the chances of blight.

6. Also, in United States, the severity of blue mold of tobacco is directly correlated with climatic

conditions viz. temperature and relative humidity during early spring. The mean temperature

for the month of January in all the tobacco growing areas of the USA directly affects the time of

sowing, and the severity of blue mold. If the mean temperature of January is above normal,

blue mold will appear earlier and the disease will be severe. If temperatures are below normal,

blue mold will appear later and the disease will be less severe.

7. Air temperature influences the epidemic development of diseases. There is an optimum

temperature for growth of any organism and there are limits of maximum and minimum

temperautres (cardinal temperatures) outside which it survives but can not grow. Paria and Raj

(1987), reported that the groundnut rust disease was favourable by Warm and Humid weather

and spread from the lower most to the 5th leaf.

8. Butler and Wadia (1992), reported that 70 % infection in groundnut leaves occurs within a 12

hour wetness period at optimum temperatures of 20-25 oC. The period of wetness after

inoculation with spore suspension must be continuous. Spread of disease within crop is

facilitated by wind movement, rain splash and insects as well. It is now well established fact

that at 35 oC, the incubation period of groundnut rust enhanced beyond 19 days and during

summer months of April and May when ambient temperatures range from 40-45 oC, rust

remain confined to host tissues without expression. They also reported that for late leaf spot

disease infection is greatest if leaf wetness is intermittent. Further the leaf spots were most

prevalent in wet areas with annual rainfall exceeding 500 - 600 mm. Also fungal infection is

highly influenced by wet periods which create surface wetness of plants.

9. Jensen and Boyle (1966) reported that the leaf wetness by rainfall, also causes germination of

conidia and produces green tube for proper infection to the host. They further observed that

rain helps spore dispersal also.

10. Rao et. al. (1994) reported that besides rain, cool temperatures of less than 20 oC also play a

role in the mechanisms of spore releases. Low rainfall (11 mm) with 89 % relative humidity

(RH) could increase disease scale and RH of 86 % may aid the entry of germ tube through

open stomata.

In terms of prevailing weather conditions, the incidence of several diseases can be even

forecast if the relationship between the weather of an area and the diseases in it can be visualised.

A very simple example is given below to understand the disease - weather relationships:

Let the range of climatic conditions for the development of the disease be represented by

D, and let C1, C2 and C3 represent the climatic conditions in region 1, 2 and 3. Following three

relationships can be established between disease and weather:

i). In first case the range of weather conditions favoring a disease (D) is entirely the outside the range

of weather (C1) encountered in the area. Therefore, the disease can not flourish in that region.


- 53 -

ii). In the second case the weather (C2) irrespective of the prevailing weather conditions, is always

favorable and lies within the limits (D) for the appearence of disease. In such cases, the

weather factors are not very important for disease forecast.

iii). In third case, which is most frequent and important one, if during the year the weather shifts

and is no longer favourable for the disease, then the disease may not occur or spread at all

that year. When weather conditions are close to or favourable for disease, the chances of

attack from the disease will be comparatively greater.

Conclusion

1. For studying plant disease development, accurate & reliable weather data of nearest

meteorological observatory be collected.

2. Quantification studies between weather variables and crop disease be worked out and in

long run, a suitable disease forecasting system can be development for sustainable

management of crop diseases under field conditions.

3. In absence of available weather data, if sufficient funds are available, then an Automatic

Weather station be purchased and installed in the field for studying micro-climate of crops

very precisely in relation with disease development for a location.

REFERENCES

1. Butler, D.R. and Wadia, K.D.R. (1992). Groundnut foliar disease, infection and leaf wetness in groundnut : A global perspective. Proceedings of an International Workshop, ICRISAT, Hyderabad, A.P., India., Nov. 25-29, 1997, pp.475.

2. Jensen, R.F. and Boyle, L.W. (1966). The effect of temperature, relative humidity and precipitation on peanut leaf spot. Plant Dis. Rep., 49 : 975-978.

3. Mather, J.R. (1974). Climatology, Fundamentals and Applications. McGraw Hill Company : 181- 214.

4. Paria, T.K. and Raj, S.K. (1987). Epidemiology of groundnut rust. Current Research, 16 : 100- 102.

5. Rao, P.A.; Ramesh Babu; G. Sarda; Jayalakshmi Devi, R. and H. Naidu. (1994). Prediction and prevention of late leaf spot on kharif groundnut. Pages 386-397, In Sustainability of Oilseeds, edited by Prasad M.V.R., Indian Soc. Oilseeds Research, Hyderabad.


- 54 -

Visit to Meteorological Observatory and Automatic Weather Station in Cropped Field at CRC

H.S. Kushwaha

Department of Soil Science, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Introduction

Since the meteorological instruments in the meteorological observatories are exposed

over the short cut grass, apparently the values of some of the important weather variables

especially the air temperature, relative humidity, leaf wetness and the wind in particular may

differ significantly from those observed in a cropped field. The major meteorological instruments

available at meteorological observatory included Stevension screen to house maximum

thermometer, minimum thermometer, dry bulb thermometer and wet bulb thermometer, three soil

thermometers each at 5, 10 and 20 cm soil depth, USWB Class A open Pan evaporimeter,

Ordinary & self recording rain gauges, Anemometer, Wind vane, Bright Sunshine recorder, dew

gauge etc. The data is recorded daily twice a day at 0712 hrs and at 1412 hrs at Pantnagar by

IMD trained meteorological observers and record is maintained in pocket registers supplied by

IMD. However, the validity of such weather data recorded at meteorological observatory at a

location from a field experiment will decrease with the distance from the meteorological

observatory. Keeping in view this constraint, for disease-weather relationship it is, recommended

& advised to monitor these important weather variables over and within the crops under natural

field conditions. These fields have variability in terms of crops their type and stage, soil

moisture, ground water table, tillage operations for soil manipulation etc. as compared with the

meteorological observatory field. Also detailed and reliable weather information is also not

available in many locations in the country due to non-availabilty of meteorological observatories.

For this purpose, a Scientific Automatic Weather Station (AWS) attached with micrologger and

Computer will be very useful for recording of weather parameters within and over the crops

accurately and then correlate them with crop observations for understanding the real crop -

weather relationships in general and disease - weather relationships in particular for major crops

of the area. There is a close relationship between crop diseases and weather variables and,

therefore, under prevailing weather conditions, the incidence of several diseases may occur in an

area and the application of chemicals in these crops will depend on the intensity and durability of

the weather conditions prevailing at particular and sensitive crop stage. The details of observations

are given below :

A. Meteorological Observatory

A plain area of 55 m (N-W) x 36 m (E-W) size with short cut grasses free from all

obstacles including highway, high building, big trees, canals, rivers and wild animals provides a

good exposure for installing all the meteorological instruments in the observatory. If a person

stands at the gate facing the observatory plot, he will find the tall instruments in the back row and


- 55 -

shorter instruments in the front rows. In general the instruments are separated at a distance of 9 m

from each within rows of 12 m apart. All observations are taken manually by meteorological

observer daily twice a day.

B. Automatic Weather Station (AWS)

A Campbell Scientific Automatic Weather Station has been designed and developed to a

very high standard for reliable measurement and recording of wide range of important

micrometeorological variables in and above the crops The station is soundly engineered and

based Campbell,s proven 21X micrologger whose comprehensive specification enables the user

to undertake virtually any monitoring task. The main and important features of the system are

described as below ::

1. Wide range of sensors : A maximum of 20 sensors can be a attached to this at a time.

2. Flexible data storage : It has Internal memory to store 19, 200 data points i.e. hourly data

for continuous 40 days at a time can be stored.

3. Versatile data transfer : Software package is available for automatic routine collection of data

at pre determined time interval which can be modified as per the need and requirement.

4. Fully protected : It has a weather proof enclosure to protect data logger and peripheral against

dust and moisture. The logger can operate over the range from - 25oC to + 50 oC without any

error.

5. Integral data processing : The processing includes the averages of maximum and minimum

averages of all weather variables, standard deviations, wind vector integration etc.

6. Robust construction : Tripod and mast are build from thick walled, galvanished steel tubing

with nickle-plated fittings. The mast is 3 metre in height with adjustable cross-arm supports for

sensors. The mast can be positoned precisely by independently adjusting tripod legs. Each leg is

provided with a flat foot with 12 mm hole which allows anchorage to the ground by stake or to

concrete. A lightning conductor and earth spike are also included to save the sensors and

datalogger from destructive effects of Thunderstorm and Lightning as and when experienced in the

area. For measurement of weather parameters in and over the Horticutural crops, a mast of 30

metre height (existing in the nearby site in the same field) can be used for sitting the sensors at

desired heights depending upon the height of horticultural crops as per the need and requirement.

7. Minimum maintenance : Once errected, the station requires very little routine attension.

8. Recording device : It has a 21 X Micrologger as recording device. It is a rugged field-proven

datalogger suitable for any application requiring data acquisition, on line data processing or

electronic control. It is compact and powerfull battery-powered device which effectively combines

the functions of micro-computer, clock, calibrator, scanner, frequency counter and controller with

one smaller enclosure. The 12 volt Nickle-Cadmium battery is chargeable by solar pannel. The

micrologger is programmed to handle almost any task including signal averaging, exite and delay,

totaling, maximum and minimum, standard deviation, scaling, 5th order polynomial processing,

low-pass filtering and wind vector calculation which are fully supported by simple program


- 56 -

statements, together with a histogram command for direct calculation of frequency distributions.

Software support is available to simplify more complex programming tasks and to avoid inspection

and processing of stored data.

Structure, Functioning and Sitting of Various Micro -Meteorological Sensors on

Automatic Weather Station

This Automatic Weather Station (AWS) is composed (Fig.1.) with various

micrometeorological instruments / sensors for monitoring the micrometeorological weather

variables such as Air temperature (oC), Relative humidity (%), Wind speed (m s-1), Wind direction

(degrees from North), Leaf temperature (oC), Leaf wetness ( % of total wet), Solar radiation (W

m-2), Net radiation (W m-2), Rainfall (mm) , Soil temperature (oC) etc. within and above the crop

canopy. A brief description of sensors measuring these weather variables is given under the

following subheads :

1. Air temperature and relative humidity

The air temperature and relative humidity in and above crop canopy are measured by

HMP 35 AC Temperature and Relative Humidity (RH) probes (two sensors). The probe contains a

Vaisala capacitive relative humidity sensor and a precision thermistor. The probe is designed to

be housed in a 41004-5 or URSI radiation shield and is attached with a 3 m long lead wire

and a connector. The length of lead wire can be increased as per the requirement.

2. Wind Speed

Wind speed in and above crop canopy is measured by A100R Switching Anemometer

(two sensors) in which a magnet rotates with the rotor spindle. The varying field forces a mercury

wetted reed switch to make contact once per resolution. This instrument is a precision

instrument which is easily interfaced with Datalogger to give accurate measurements of wind run

or mean wind speed in m/s. This instrument is constructed from anodised aluminium alloy,

stainless steels and weather resisting plastics. A stainless steel shaft runs in two precision,

corrosion-resistant ball races. The bearings are protected from the entry of moisture droplets

and dust, resulting the instrument suitable for permanent exposure to the weather. Its sensitivity

is 0.80 revolutions per metre with an overall accuracy of 2 % + 0.1 m s-1.

3. Wind Direction

The wind direction at 3 m height is measured by W200P Potentiometer Wind Vane (one

sensor). This instrument is manufactured by Vector Instruments Ltd. and measures the wind

direction directly in degrees from North. The windvane incorporates a 358 degree micro - torque

potentiomter (wire wound type). The 2 degree gap is filled to ensure operation and a long service

life. The precision ball - bearing races are corrosion - resistant and are protected against the

entry of moisture and dust.

4. Leaf Temperature :

The temperature (oC) of leave is measured by K-Type Thermocouples (two sensors).


- 57 -

Copper and constantan thermocouple wires were twisted to form the sensors and are connected

to the leaves of the plants. There is provision of adding two more leaf temperature sensors.

5. Soil Temperature :

The soil temperature (oC) at 10 and 20 cms soil depths are measured by 107 Thermister

Probes (two sensors). These probes incorporate a precision thermistor in a water resistant probe

with a standard 3 m long cable.

6. Leaf Wetness Period :

The duration of leaf wetness at crop surface is measured by 237 Wetness Sensing grid.

This grid is suitable for a range of Scientific and Industrial wetness sensing applications. It

provides a simple measure of the degree of wetness of the surface to which they are attached /

exposed and they can also be used to measure the percentage of time for which the surface is

wet or dry. The sensor consists of a rigid epoxy circuit board (75 mm x 60 mm) with interlacing

gold - plated fingers. Condensation or rain on the sensor lowers the resistance between the

fingers which is measured by the datalogger.

7. Solar Radiation :

The Solar or Global radiation at 3 m height is being measured by SP1110 Pyranometer

sensor (one sensor). This is a compact high - output thermally stable solar radiation sensor. The

cosine- errected head contains a special high grade Silicon Photocell sensitive to short-wave

radiation with wavelength between 350 and 1100 nm. The head is completely sealed and can be

left indefinitely in exposed conditions. A levelling mount is also available which enables the

pyranometer to be accurately positioned. The output is 10 mv / 1000 W m-2 with excellent

linearity.

8. Net Radiation :

The net radiation which is the difference between the incomming solar radiation and the

outgoing radiation received on the crop surface is being measured by Q -7 Net Radiometer (one

sensor). This instrument is high - output thermopile sensor which measures the algebraic sum of

incoming and outgoing all - wave radiation (i.e. short- and long - wave components). Incoming

radiation consists of direct (beam) and diffuse plus long wave irradiance from the sky. Outgoing

radiation consists of reflected solar radiation plus the terrestroal long-wave components. It

consists 60 - junction thermopile with low electrical resistance. The top and bottom surfaces are

painted black and are protected from convective cooling by hemispherial heavy duty

polyethelene windshileds.

9. Rainfall :

The rainfall is measured by ARG 100 Aerodynamic Tipping Bucket Raingauge (one

sensor). It is a well designed tipping bucket raingauge which combines durable construction

with very reasonable cost. The gauge offers less resistance to air flow and helps to reduce the

sampling errors that inevitably occur during wind - driven rain. This instrument is constructed from


- 58 -

UV - resistant, vaccum - moulded plastic and consists of a base and an upper collecting funnel.

The base splits into two parts, the inner section supporting the tipping - bucket mechanism and

the outer providing protection and allowing the unit to be bolded firmly to a suitable mounting

plinth or concrete slab. The gauge resolution is 0.2 mm / tip. the funnel diameter is 25.5 cms.

10. Micrologger enclosure:

All the sensors and the logging equipment are supported on a sturly tripod and mast. A

fiberglass housing with lock and key provides as excellent environmental protection for the

datalogger and ancillary equipment. Glass fitted nylon water proof connectors are fitted to the base

of the enclosure and sensors may be removed or replaced with minimum disturbance to the

weather station.

C. Recording & Data Logger Programming in Automatic Weather Station

All these above sensors have been hooked into the 21X Micrologger (Datalogger) which

runs through a chargeable battery charged with Solarex Solar Panels. In order to record the

output of these sensors, a datalogger programme has been prepared in the Computer

depending upon the number of the sensors attached with different channels in the datalogger and

also the frequency and time of observations. This has been done with the help of micro -

programmes developed in the Computer, and the output is converted into the desired units for

each weather variable. Each variable is sensed after each minute and an integrated value

over a period of five minutes is calculated. Twelves such values of each data point is totalled

or averaged over a period of say one hour and is stored in the memory of the datalogger at an

appropriate location at each hour of the day. The data is also averaged or totalled from each

day called Julian day (i.e. the day of a year from Ist January) from the date of planting / sowing

of the crop in the field. In the present study the recording of micrometeorological weather

variables by AWS were started one month before the first sowing of potato crop and continued till

the end of the Potato crop season. The crop var. Kufri Bahar which is sensitive to Late Blight of

Potato was planted in three dates viz. D1 (21 - 10 - 2008), D2 (06 - 12 - 2008) and D3 (21 -12 -

2008) under four irrigation treatments viz. one irrigation, two irrigations, three irrigations and four

irrigations. The observations on micro-meteorological variables in crop field since October 01,

2008 and will continue till harvesting of crop of all planting dates depending upon the maturity of

crop in March 2009. The incidence of Late Blight of Potato is monitored on day by day basis and

will continue till maturity of crop in all plots. The recording of micro- meteorological data

observations is also continuing till date. The current data of this hour can be noted on the provided

sheet. At a time, the micro-meteorological data of last 40 days can stored in this datalogger and it

can be seen on hourly basis on liquid crystal display (LCD) of the datalogger.

From this data logger each week the micro-meteorological data thus stored in its memory

is transferred into the SM 192 Storage Module by connecting it to the 9 - pin serial I / O port. This

Storage Module is taken to the laboratory and connected to the Computer. From SM -192 using

SC – 532, 9 - pin Peripheral to RS - 232 interface, the data is then transferred into the Computer


- 59 -

in ASCII form using SMCOM programmes developed for this purpose in the form of a Computer

file. From this file the data is then splitted into the hourly as well as into daily values using splitting

programmes like SPLIT 03. PAR and SPLIT 04. PAR, respectively, which have also been

development on Computer. The data will then be used for identification of micro-meteorological

weather conditions conducive for the occurrence of late blight of potato during the 2008-09

season.

Data Sheet for Recording of Current Observations of Micro-Meteorological Variables in The

Potato Field at Crc Using Automatic Weather Station

The current micro-meteorological weather variables are being recorded by Automatic

Weather Station (AWS) in the field from 01-10-2008 and the date of planting of Potato crop var.

Kufri Bahar in plot is 21-10-2008 during this Rabi season of 2008 - 09 at Crop Research Centre

of the University. The current data can be read on Liquid Crystal Display (LCD) of the Datalogger

of the AWS in the table given below in the specific sequence of attached sensors :

1. Name of the crop : Potato 2. Date of Ist planting of crop : 21-10-2008

3. Stage of the crop : Tuber Formation 4. Julian day : 48

5. Date of observation : 17-12-2008 6. Time of observation : 1600 hrs

-----------------------------------------------------------------------------------------------------------------------------------

S.No. LOCATION NO. WEATHER VARIABLE HEIGHT UNITS

----------------------------------------------------------------------------------------------------------------------------------

1. 1 Relative Humidity 1 3m %

2. 2 Air Temperature 1 3m oC

3. 3 Relative Humidity 2 crop %

4. 4 Air Temperature 2 crop oC

5. 5 Net Radiation crop W m-2

6. 6 Solar Radiation 3m W m-2

7. 7 Soil Temperature 1 10 cm depth oC

8. 8 Soil Temperature 2 20 cm depth oC

9. 9 Leaf Wetness crop %

10. 10 Wind Direction 3m Degrees

11. 11 Wind Speed 1 3m m s-1

12. 12 Wind Speed 2 crop m s-1

13. 13 Rainfall crop mm

14. 14 Leaf Temperature 1 crop oC

15. 15 Leaf Temperature 2 crop oC


- 60 -

Technology Transfer: Experiences of Uttarakhand

K. P. Singh and R. P. Singh Directorate of Extension Education, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

“Our basic strategy for social and economic transformation of India towards its vision as

developed society by 2020, would be a strong focus on providing urban amenities in rural

areas in a most creative and cost effective manner.” Dr. APJ Abdul Kalam

The greatest challenges to our society, in the developing world, today are hunger, poverty and

peace - the number one millennium goal of the United Nation. Despite of known as growing

economy in the world, the weaker and poor section of our country is still unprivileged. In fact, we

have followed a path of skewed development in favour of mainly economic gains. No doubt, we did

so well on the economic front. The two-third of the well-to-do farming families benefited from the

conventional development efforts, but the one-third remained poor. The gulf between rich and

poor, in fact, has increased many folds. As it was observed by late Shri Rajiv Gandhi, the then

Prime Minister of India that “only 18 percent of the total resources earmarked for the rural poor

reached them”.

The country, after independence, initiated many rural development programme starting

from Community Development Programme to T&V. At present, the extension is dealt by line

departments of State Governments, Directorate of Extension Education of different SAUs, and

recently originated, ATMA. Despite of all above, the gap of lab and land is not bridged up and most

of the programmes could not prove to be socio-economically encouraging for the end users i.e.

farmers and rural entrepreneurs. Some of the most important problems of extension systems

visualized are:

1. Public extension services are widely viewed as supply driven rather than demand driven.

2. Commercialization of agriculture gave rise to specialized client and demand for location

specific extension services which are not catered by public extension system.

3. Public extension deals with a large area, large population and diverse cropping pattern.

Extension services provided are general in nature rather than specific and intensive.

4. High cost, low impact of extension programmes, growing conflicts between farmer farmer's

interest and interest and policy goals, poor motivation of staff and conflicting roles are

observed in public extension.

5. Insufficient interface between extension workers and farmers.

6. Inadequate funds for operational purposes.

7. Majority of the extension services are curative in nature.

8. Inadequate technical qualifications of village level extension workers.

9. Incomplete and inadequate extension services.

10. Inadequate internal organizational structure.

11. Inefficiency of extension personnel.


- 61 -

12. Inappropriateness or irrelevance of extension content.

13. Dilution of impact.

By and large, we have developed a uniform extension system and strategies for the

country till date, as a whole, which favoured the rich, well-to-do farmers or well endowed areas.

We also heavily leaned only on crops rather than horticulture, animal husbandry and other allied

fields. We did not evoke partnership between public and private institutions for added investments

in agricultural extension. The present extension strategies must differ for different agro-eco

systems as well as for the most backward regions and districts, which have suffered deprivations

and are poorest of the poor. Today, its high time to realize that the extension system should insist

on demand driven strategy with adequate focus on training and entrepreneurship development for

rural youth consistent to the millennium goals. Our training strategy should include bringing

“training and entrepreneurship development” at par with teaching, research and extension as the

fourth basic function of the agricultural institutions.

Agriculture in Uttarakhand:

Uttarakhand state agro-climatically falls under Zone 9 and Zone 14 of nationally described

agro-climatic zones. The state is further divided into four sub-zones on the basis of the altitude,

aspects, rainfall and soil type.

Zone A Lower hill (below 1000 m above msl), alluvial-alluvial sandy; rainfall 900-

2400 mm

Zone B Mid-hills (1000-1500 m above msl); sandy loam; rainfall 1200-1300 mm

Zone C High hills (1500-2400 m above msl)

Zone D Very high hills (2400 m above msl)

The economy of Uttarakhand is predominantly agrarian. With forests cover around 64% of the

total area of the Uttarakhand, the area of cultivable land is very less. More than 4/5th of the working

population is directly engaged in agriculture even though only 12% of the total land area is under

agriculture. Only 13% of the total area is irrigated, almost 64% of which is fed by natural springs.

Agriculture is heavily dependent on energy flows from uncultivated lands such as forests

and grasslands recycled into manure through livestock (therefore these lands are called as

"support lands"). Animals are reared mainly for their dung. A large proportion of the fodder for

these animals also comes from the "support" lands. Thus forests, livestock and agriculture formed

an interconnected and interlinked whole. Keeping this interlinked nature of the Farming System in

mind it is very important understanding why a single intervention focusing only on one of the above

components may not yield desired results.

Problems of hill Agriculture

The main problems of hill agriculture include undulating terrain, harse climate, fragile eco-

system, rainfed agriculture, small and fragmented land holdings, high level of soil degradation,

sparse population, poor means of transportation and communication, migration of male folk

therefore women centered agriculture, low risk bearing capacity of farmers, lack of mechanization,


- 62 -

subsistence agriculture and poor agricultural productivity.

Developmental interventions in the region generally start with only one particular sector-

such as agriculture, horticulture, animal husbandry, forestry, etc. due to the sectoral nature of

Government approach. As a result they end up focusing on only one aspect of people's

livelihood. Large sums of money are therefore pumped into these regions in the name of

development but are wasted because of lack of a holistic outlook.

Possible Solutions for Agricultural Development in Uttarakhand and other hill states

Watershed approach to hill agriculture

Participatory mode of extension; progressive farmers should be a part of our planning and

experimentation first.

Human resource development programmes should encompass not only considers only

employees and extension personnel but farmers should also which are a very potential

Human Resource.

Thrust should be given on farmer to farmer extension.

Technology evaluation and refinement through KVKs should be further strengthened to be

more of innovative nature .

Indigenous Technological Know-how (ITKs) existing almost every where since ages should

be collected, documented, validated scientifically and good ones popularized aggressively.

Plastic culture - alkathethen water storage structures, poly mulch, low poly tunnel and poly

houses are boon to the hills therefore, should be given priority and support for

popularization.

Off- season vegetable cultivation

Agro-based small industries' should be encouraged

Commodity and area specific beneficial organic farming needs to be popularized.

Value addition not only in terms of processing but also production, protection practices as

per market demand.

Self Help Group (SHG) has emerged as a formidable design to organize the needy and

poorer sections of the society especially the rural or urban women through credits.

Development of marketing chain to ensure the remunerative prices to the farmers.

A better approach could be the identification and promotion of technologies that strengthen

the linkages of the hill farming system. In order to make agribusiness a profitable venture it is

necessary to have a holistic approach to various activities inherent to it. In order to realize the true

potential, it is necessary to establish efficient linkages between storage and marketing. In addition

to providing sufficient storage capacity, it is also necessary to introduce a sound marketing system

so as to minimize losses. The Panchayats can help to develop the linkages. In addition to

formation of linkages, through Panchayats, self help groups (SHG) can also help to extend micro

finance as viable tool for extending credit to the poor farmers which in turn will help in risk

management arrangements as a measure to improve profitability. Panchayats, and SHGs can also

play an important role in organizing awareness camps through imparting trainings on their

specialized needs.


- 63 -

Recent Advances in Management of Bacterial Diseases of Subtropical

Fruits

Ram Kishun Central Institute for Subtropical Horticulture, Rehmankhera, P.O. Kakori, Lucknow-227 107.

In independent India farmers have adopted modern method of cultivation to get the

maximum returns. The modern method of cultivation made crops more susceptible to the number

of diseases caused by fungi, bacteria, viruses, mycoplasmas and other agencies. Initially fungal

and viral diseases attracted the workers and good progress has been made on their various

aspects particularly in cereals, pulses, cash crops etc. Work on bacterial diseases of fruits, started

little late, though they are equally important and cause considerable loss to the crops. In India

much emphasis has not been given on bacterial diseases of fruits except a few. The bacterial

diseases of subtropical fruits, reported time to time in India are presented in Table 1.Out of these,

mango bacterial canker disease, citrus bacterial canker disease, bacterial blight of pomegranate,

grapevine bacterial canker disease, Moko wilt of banana etc. are studied well as compared to

others.

Table 1: Some important bacterial diseases of tropical/subtropical fruits

Disease Causal pathogen Brief symptom Distribution

Mango (Mangifera India L.)

Mango bacterial canker disease (MBCD)

Xanthomonas campestris pv. mangiferaeindicae

Brown to blank cankerous, raised lesions on all the parts and surrounded with halo on leaves. Dark brown streak on stones.

Most of the mango growing areas of the country.

Citrus (Citrus spp.)

Citrus bacterial canker disease (CBCD)

Xanthomonas axonopodis pv. citri

Cankerous and raised lesions on leaves, twigs, older branches, thorns and fruits. Pathogen attacks acid lime roots too.

All the citrus growing areas.

Banana (Musa spp.)

Moko disease/ Bacterial wilt

Burkholderia (Ralstonia) solanacearum

Rapid wilting, collapse of leaves, premature ripening and discolouration of vascular strands.

West Bengal and Tamil Nadu.

Bacterial soft rot of rhizome and pseudostem

Erwinia chrysanthemi pv. paradisiaca

Externally, yellowing and wilting of leaves. Internally, soft odorous rot, decay and vascular discolouration.

West Bengal

*Present Address: 8/202 Indira Nagar, Lucknow-226016


- 64 -

Disease Causal pathogen Brief symptom Distribution

Rhizome rot Erwinia carotovona subsp.carotovora

Odorous decay and vascular discolouration.

Tamil Nadu

Bacterial top rot

Erwinia carotovora subsp. carotovora

Top rotting, tip shrivelling, blackening and death of suckers.

Tamil Nadu

Bacterial leaf spot

Xanthomonas musicola (Not listed in valid list)

Streaks along the veins, chlorotic patches, stunting and reduction in bunches.

Tamil Nadu

Grapevine (Vitis vinifera L.)

Grapevine bacterial canker disease (GVBCD)

Xanthomonas campestris pv. viticola

Water soaked, dark brown, angular lesions on leaves and cankerous on petioles, canes and berries.

Andhra Pradesh, Karnataka, Maharashtra and Tamil Nadu

Crown and root gall

Agrobacterium tumefaciens, Rotylenchulus reniformis and Fusarium solani

Spherical, oblong, convolvulated galls, retarded growth and sickly appearance.

Andhra Pradesh

Pomegranate (Punica granatum L.)

Bacterial blight Xanthomonas axonopodis pv. punicae

Dark brown spots with water soaked margin on leaves, fruits and nodes.

Delhi, Haryana, Himachal Pradesh and Karnataka

Karonda (Carissa carandas L.)

Canker Xanthomonas campestris pv. carissae

Small, round, water soaked, translucent spots on leaf, raised at lower surface but not much on upper. Similar symptoms on twigs.

Maharashtra and Rajasthan

Bael (Aegle marmelos (L.) Correa)

Bacterial shot hole and fruit canker

Xanthomonas campestris pv. bilvae

Round brown lesions with shot hole surrounded by oily raised margins on leaves and rough and corky on twigs and fruits.

Maharashtra and Rajasthan

Detection of Pathogens

Much work has not been conducted towards detection of bacterial pathogens in fruit trees

in India. However, some attempts have been made by development of semi-selective medium for

Xanthomonas campestris pv. mangiferaeindicae. Bacterial viruses specific to their respective

hosts were isolated in case of MBCD and GVBCD pathogens which can be utilized for rapid

detection of these pathogens.

Variability in Pathogens

Diversity exists in MBCD pathogen and 3 to 10 groups were detected on the basis of

cultural and biochemical characters, their isozyme and sugar utilization pattern, reaction on mango

genotypes, antibiotic sensitivity and lipid profile. Occurrence of pathotypes (strains) are reported in

X. axonopodis pv. citri which varied from 3 to 6 on the basis of morphological and biochemical

characters and its reaction on host plants. Acid lime strain of the pathogen is reported more


- 65 -

specific. Much work has not been conducted on Moko wilt pathogen but its resemblance with

biotype II and III of the bacterium was confirmed. In case of X. campestris pv. viticola, presence of

group is detected by fatty acid profiles. Strains as such are not detected in X. axonopodis pv.

punicae but it appears that the strains isolated at Bangalore in 1991is different from the earlier

isolated from North India.

Survival and Spread

Most of the bacterial diseases of fruit crops survive on the tree itself and spread through

wind splashed rain. Bacterial pathogens enter in host through natural openings / wounds and long

distance dissemination takes place through infected parts / planting materials. Detailed studies

have not been conducted on disease cycle of these bacterial diseases except MBCD, CBCD,

GVBCD, pomegranate bacterial blight and karonda canker.

Apart from its survival on tree, MBCD pathogen also survives in diseased leaves up to 8

months. Bacterium is reported pathogenic on number of other hosts. It is also reported to survive

in mango stones and a number of weeds are reported as symptom less carrier for the pathogen. In

new area disease spreads through infected planting material and from diseased to healthy plants

by wind splashed rain. A dozen insects are reported associated in mechanical transmission of this

pathogen.

The main source of inoculums in case of CBCD is cankerous leaves, twigs and branches.

The bacterium survives up to 6 months in defoliated leaves and 76 months in twigs. The pathogen

is carried from season to season mainly in the cankers on twigs and branches. It enters in the host

through stomata and wounds and presence of free moisture on the host surface for 20 minutes is

essential for successful infection. Bacteria from cankers are mostly disseminated by wind splashed

rains. Citrus leaf miner (Phyllocnistis citrella) plays an important role in dissemination of CBCD and

its long distance spread is due to transfer of infected planting material.

Moko wilt pathogen (Ralstonia solanacearum) survives in soil in presence of susceptible

host and spreads through infected suckers, tools, implements etc. The survival of GVBCD is

mainly on infected plant parts in vine yards. It also survives in infected dry leaves (up to 65days)

and in moist soil (35 days). Pathogen was found to infect Pyllanthus maderaspatensis and mango.

Secondary spread takes place through wind splashed rain. It spreads to distant places through

infected cuttings. The causal bacterium of karonda pathogen is reported to survive in diseased

plant debris. Under artificial inoculation it was found to infect 2 hosts, i.e., Cestrum nocturnum and

Thevetia nereifolia. Bacterium enters in host mainly through stomata and wounds.

Epidemiology

The MBCD is favoured by high relative humidity (>90%) and temperature range of 25 to

300C. Disease has been found more active under field conditions during monsoon (July–

September). Though the temperatures from April onwards remain favourable (28-300C) but fresh

infection does not occur until it rains. However, in infected trees, infection starts early in the last

week of April and continues to increase even in the dry weather of May. CBCD is favoured by


- 66 -

good evenly distributed rain with temperature in between 20 and 300C. Citrus leaf miner also helps

in increase in disease severity. The temperature range of 25 to 300C has been found more suitable

for GVBCD and its pathogen. Presence of free water on leaf surface and more number of rainy

days favours the disease. It has been reported that the pomegranate bacterial blight intensity

increases with high temperature and low humidity and the karonda bacterial canker with the mean

temperature and relative humidity of 240C and 56 per cent.

Management

Cultural

Regular inspection of orchards, sanitation, seedling certification and use of healthy stones

for root stock are recommended as preventive measures against MBCD. Moko wilt of banana can

be managed by quarantine, inspection, better drainage, destruction of collateral hosts and infected

mats, summer ploughing and crop rotation. Clean cultivation and use of healthy planting materials

are recommended against soft rot of banana rhizome and pseudo-stem and pomegranate

bacterial blight. Pruning helps in reduction of GVBCD, karonda bacterial canker and CBCD.

Chemical

MBCD on fruits has been reduced by Agrimycin-100 (0.025 %) fruit dip. Two sprays of

Streptocycline (0.02-0.03 %) at 20 days interval have also reduced the fruit infection. Monthly

sprayings of Bavistin (0.1 %) proved effective against MBCD. Stem injection of Bavistin (0.01 %)

has been found effective on 3 to 4-yrs-old mango seedlings. Mixture of 2 chemicals, such as

Copper oxychloride (0.3 %) +Agrimycin-100 (0.01 %) and Bavistin (0.1 %) + Agrimycin-100 (0.01

%) have been tried but Bavistin (0.1 %) alone proved better than the combinations. Essential oil

from Anacardium occidentale have been reported effective against X. campestris pv.

mangiferaeindicae.

CBCD (X. axonopodis pv. citri) is reduced by spraying of Bordeaux mixture (1%) along with

pruning of infected plant parts before monsoon. Pruning along with 3 to 4 sprays of 1 per cent

Bordeaux mixture are reported effective. Two pruning of infected plant parts along with 4 sprays

of Copper oxychloride (0.5 %) or Bordeaux mixture (1%) have been reported effective and

economical. Streptomycin Sulphate (0.05-0.1 %) is reported effective when sprayed with glycerine

(1%) on acid lime. Sprayings of a mixture of Streptocyline (0.05 %) + Bordeaux mixture (1 %) and

Streptocycline (0.01 %) + Copper oxychloride (0.1%) have been found economical in management

of CBCD. Application of neem cake solution on the foliage has also been reported effective

against CBCD in nurseries. Soft rot of rhizome and pseudo-stem (Erwinia chrysanthemi pv.

paradisiacal and E. carotovora subsp. carotovora) has been reduced by drenching of bleaching

powder (2 g l-1) at an interval of 10 to 15 days. Soil treatment with methoxy-ethyl-mercury chloride

(0.01 %) is reported effective against E. carotovora pv. carotovora. Dipping of suckers in

chlorinated water before planting also helps in reduction of disease. Sprayings of Streptocycline

(0.03 %), starting from 2 leaf stage upto 70 days at an interval of 15 days are reported effective

against GVBCD. Sprayings of Bordeaux mixture (1%) and Copper oxychloride (0.3 %) have also


- 67 -

been found effective against GVBCD.

Spraying and pasting with Copper oxychloride (0.3 % ) or Bordeaux mixture (1%) have

been found effective in reducing pomegranate bacterial blight, while karonda canker has been

reduced by spraying of Phytomycin (0.02 %).

Biological

Five antagonistic bacterial organisms isolated from mango phylloplane, mango fruit surface

and organic liquid pesticides have been found effective in reducing MBCD. Out of these five two

were identified as Bacillus coagulans and Pseudomonas fluorescens. B. amyloliquifaciens and B.

subtilis are also reported effective against MBCD pathogen. Similarly bacterial micro-organisms,

Bacillus subtilis, Erwinia herbicola and P. fluorescens isolated from citrus leaves showed inhibitory

effects against X. axonopodis pv. citri in vitro. These antagonists can be utilized in bio-control of

CBCD under field conditions.

Antagonistic crops such as garlic, sorghum etc. and bacterization with P. fluorescens are

reported effective in suppression of Moko wilt. Information on bio-control of other bacterial

diseases of fruits is lacking.

REFERENCES

1. Kishun, R. (1993). Bacterial diseases of fruits. In: Advances in Horticulture Vol. III, Fruit Crops (Eds K. L. Chadha and O. P. Pareek). Malhotra Publishing House, New Delhi, pp. 1389 – 1406.

2. Kishun, R. (1995). Detection and management of Xanthomonas campestris pv. mangiferaeindicae. In: Detection of Plant Pathogens and Their Management (Eds J. P. Verma, A. Varma and Dinesh Kumar). Angkar Publishers (P) Ltd, New Delhi, pp. 173 – 182.

3. Kishun R. (1996). Bacterial diseases of tropical fruits. In: Advances in Diseases of Fruit Crops in India (Ed. S. J. Singh). Kalyani Publishers, Ludhiana, 345 – 362.

4. Kishun, R. (1996). Status of bacterial diseases of fruits crops in India. In: Disease Scenario in Crop Plants Vol. I (Eds V. P. Agnihotri, Om Prakash, R. Kishun and A. K. Misra), International Books & Periodicals Supply Service, New Delhi, pp. 91 - 113.

5. Kishun, R. (2002). Mango bacterial canker disease and its management strategies. In: Crop Pests and Disease management: Challenges for the Millennium (EDS D. Prasad and S. N. Puri). Jyoti Publishers, New Delhi, pp. 253 – 259.

6. Kishun, R. and Chand, R. (1995). Changing situation in relation to bacterial diseases of fruits. In: Proceedings National Seminar on Changing Pest Situation in Current Agriculture Scenario of India. Publication and Information Division, ICAR, New Delhi, PP. 375 – 383.

7. Kishun, R., Mishra, Dushyant, Ram,R. A. and A. K. Verma (2006). Management of mango bacterial canker disease through antagonist. J. Eco Agric., 1 (1):54 – 56.

Electron Microscopy: A Tool for study of Ultrastructural Pathology


- 68 -

Balwinder Singh Dhote

Department of Anatomy, G.B.P.U.A.&T., Pantnagar - 263145 (Uttarakhand)

Introduction

One of the most important tasks in the education of a pathologist is learning to distinguish

normal from abnormal tissues. Typically, training

programs provide an adequate background for the

examination and interpretation of tissues at the

gross and light microscopic (lm) levels, leaving the

student pathologist to his/her own devices to

develop necessary skills at the ultrastructural level.

The purpose of this presentation is to facilitate

development of these skills in ultrastructural

examination/interpretation of tissues, by providing a

starting point, some tools for study, direction, and

finally, a goal at which to aim. Since it would be

unrealistic to attempt to go into depth in the short

time allotted, the presentation will concentrate on

an approach to interpretation of ultrastructural

cases while providing a broad overview of some

commonly examined tissues.

A human eye can distinguish two points 0.2mm apart. Man’s quest to see the unseen and

beyond what can be seen with the naked eye led to the discovery of simple magnifying glass that

produces an enlarged image of an object. Further improvement led to development of light

microscopes that use a combination of magnifying glasses/lenses. Dr.Ernst Ruska at the

University of Berlin built the first Electron Microscope (a Transmission Electron Microscope) in

1931 and could get a resolution of 100nm using two magnetic lenses. Today using 5-7 magnetic

lenses in the imaging system a resolution of 0.2nm can be achieved. The introduction of the

electron microscope as a tool for the biologist brought about a complete reappraisal of the micro-

anatomy of biological tissues, organisms and cells. In the early days of its application to biological

materials, it was the tool of anatomists and histologists, and many previously unimagined

structures in cells were revealed. More recent developments in biological specimen preparation

have come from biochemists and physicists who have used the electron microscope to examine

cells and tissue in many different ways.

The two most common types of electron microscopes available commercially are the

TRANSMISSION ELECTRON MICROSCOPE (TEM) and the SCANNING ELECTRON

MICROSCOPE (SEM). In the SEM, the specimen is scanned with a focused beam of electrons

which produce "secondary" electrons as the beam hits the specimen. These are detected and


- 69 -

converted into an image on a television screen, and a three-dimensional image of the surface of

the specimen is produced. Specimens in the TEM are examined by passing the electron beam

through them, revealing more information of the internal structure of specimens.

The Transmission Electron Microscope (TEM)

The TEM is an evacuated metal cylinder (the column) about 1 to 2 meters high with the

source of illumination, a tungsten filament (the cathode), at the top. If the filament is heated and a

high voltage (the accelerating voltage) of between 40,000 to 100,000 volts is passed between it

and the anode, the filament will emit electrons. These negatively charged electrons are

accelerated to an anode (positive charge) placed just below the filament, some of which pass

through a tiny hole in the anode, to form an electron beam which passes down the column. The

speed at which they are accelerated to the anode depends on the amount of accelerating voltage

present.

Electro-magnets, placed at intervals down the column, focus the electrons, mimicking the

glass lenses on the light microscope. The double condenser lenses focus the electron beam onto

the specimen which is clamped into the removable specimen stage, usually on a specimen grid.

As the electron beam passes through the specimen, some electrons are scattered whilst

the remainder are focused by the objective lens either onto a phosphorescent screen or

photographic film to form an image. Unfocussed electrons are blocked out by the objective

aperture, resulting in an enhancement of the image contrast. The contrast of the image can be

increased by reducing the size of this aperture. The remaining lenses on the TEM are the

intermediate lens and the projector lens. The intermediate lens is used to control magnification.

The projector lens corresponds to the ocular lens of the light microscope and forms a real image

on the fluorescent screen at the base of the microscope column.


- 70 -

Resolving Power

The human eye can recognize two objects if they are 0.2mm apart at a normal viewing

distance of 25 cm. This ability to optically separate two objects is called resolving power. Any finer

detail than this can be resolved by the eye only if the object is enlarged. This enlargement can be

achieved by the use of optical instruments such as hand lenses, compound light microscopes and

electron microscopes.

Resolution in the light microscope

In the light microscope, the quality of the objective lens plays a major role in determining

the resolving power of the apparatus. The ability to make fine structural detail distinct is expressed

in terms of numerical aperture (NA). The numerical aperture can be expressed as n sinα where n

is the refractive index for the medium through which the light passes (n air =1.00; n water = 1.33; n

oil = 1.4), and α is the angle of one half of the angular aperture of the lens. Light microscope

objective and condenser lenses are usually designated by this NA value.

In a light microscope, a beam of light is directed through a thin object and a combination of

glass lenses provide an image, which can be viewed by our eyes through an eye piece. The image

formed is realistic, because it uses visible multicolor light. Visible light has wave like nature with a

wavelength (λ) of 400-800 nm. Since the resolution cannot be less than half the wavelength (λ),

the ultimate resolution attainable by using the light microscope is 200nm. This corresponds to a

magnification of 1000 times as compared to an eye. Any magnification higher than this will not

resolve more detail but will only give “empty magnification”.

( 1mm = 1000 µm; 1 µm = 1000nm; 1nm = 10 A0 )

Changes in resolution with wavelength (light microscope)

Light source Green Blue Ultraviolet

Wavelength (nm) 546 436 365

Resolution (nm) 190 160 130

Resolution improves with shorter wavelengths of light

It can be seen from the above table that resolving power improves as the wavelength of the

illuminating light decreases. To explain this more fully, the resolving power of the optical system

can be expressed as

where

R is the distance between distinguishable points (in nm),

is the wavelength of the illumination source (in nm),

NA is the numerical aperture of the objective lens.


- 71 -

The optimal resolving power for a light microscope is obtained with ultraviolet illumination

( = 365) if a system with the optimal NA is used (1.4).

In this example

R = 130.4 nm

In the visible region of the spectrum, blue light has the next shortest wavelength, then

green and finally red. If white light is used for illumination then the applicable wavelength is that for

green. This is in the middle range of the visible spectrum and the region of highest visible

sharpness.

Improvement of resolving power

Due to this limitation of resolving power by light microscopy, other sources of illumination,

with shorter wavelengths than visible light, have been investigated. Early experiments using X-rays

of extremely short wavelength were not pursued further because of the inability to focus these

rays. The first breakthrough in the development of the electron microscope came when Louis de

Broglie advanced his theory that the electron had a dual nature, with characteristics of a particle or

a wave. The demonstration, in 1923 by Busch, that a beam of electrons could be focused by

magnetic or electric fields opened the way for the development of the first electron microscope, in

1932, by Knoll and Ruska. Although the initial development of the electron microscope, in

Germany, was followed by technical improvements in America, the first commercially available

apparatus was marketed by Seimens.

Specimen preparation for TEM

The greatest obstacle to examining biological material with the electron microscope is the

unphysiological conditions to which specimens must be exposed.

Since the material must be exposed to a very high vacuum ( to Torr) when being

examined, it must be dried at some stage in its preparation. The biological specimen must be

stabilized (or fixed) so that its ultrastructure is as close to that in the living material when exposed

to the vacuum.

The limited penetrating power of electrons means that the specimens must be very thin or

must be sliced into thin sections (50 - 100 nm) to allow electrons to pass through.

Contrast in the TEM depends on the atomic number of the atoms in the specimen; the

higher the atomic number, the more electrons are scattered and the greater the contrast.

Biological molecules are composed of atoms of very low atomic number (carbon, hydrogen,

nitrogen, phosphorus and sulphur). Thin sections of biological material are made visible by

selective staining. This is achieved by exposure to salts of heavy metals such as uranium, lead

and osmium, which are electron opaque.

Fixatives are used to prevent autolysis, change in volume and shape and preserve various

chemical constituents of the cell.


- 72 -

Aims of Fixation

To preserve the structure of cells and tissues with minimum or least alteration from the

living state.

To protect them against alterations during embedding and sectioning.

To prepare them for subsequent treatments such as staining and exposure to the electron

beam

Commonly used Fixatives

Glutaraldehyde

Paraformaldehyde Primary fixative

Acrolein

Karnovsky’s Fixative (Glutaraldehyde + Paraformaldehyde)

Osmium tetroxide Secondary fixative

Some other compounds are also there which have the ability to partially fix or stain the

cellular constituents e.g. Chromium salts, Uranium salts, lead compounds and Phosphotungstic

acid (PTA).

Procedure of Fixation and Block Making

Primary fixation

1-2mm sq thick samples + 2.5% glutaraldehyde made

in 0.1M sodium phosphate buffer (pH 7.4) 2-24 hours at 4°C

Washing

Rinse thoroughly with 0.1 M sodium phosphate buffer (pH 7.4) to wash away excess fixative

Secondary fixation

Osmium tetroxide (1% solution) is commonly used, acts as electron dense stain reacts principally

with lipids.

Washing

Rinse thoroughly with 0.1 M sodium phosphate buffer (pH 7.4) to wash away excess fixative

Dehydration

Ethanol or Dry acetone is used to completely dehydrate the tissue.

Clearing

Xylene, Toluene or epoxy propane is commonly used.

Infiltration

Infiltration is done by gradually decreasing the concentration of clearing agent and proportionately

increasing the concentration of embedding medium.

Infiltration is carried out with liquid resins.

Embedding

Embedding is done in the embedding medium using a gelatin or beam capsule

Polymerization


- 73 -

Keep the specimen at 40-50°C for overnight for better penetration of the resin and then increase

the temperature to 60°C for 24-48 hrs so that the resin gets hardened.

Removing the Blocks from the mould

After polymerization the blocks can be easily removed.

ULTRAMICROTOMY

Glass knife is used for cutting ultrathin sections. Ultrathin sections show interference colors while

floating on the liquid of the trough. This makes it possible to determine the thickness of the

sections.

Gray-60 nm (600A0 ); optimal for high resolution work.

Silver- 60-90 nm; ideal for most of the purposes.

Gold- 90-150 nm; useful for low magnification and autoradiography.

Purple ,blue,green and yellow- range from 150-320nm; very thick sections and not suitable for

transmission microscopy.

He sections are picked on to the grids to be observed in the TEM

Tem Observations

One of the most important tasks is learning to distinguish normal from abnormal tissues. In

order to successfully interpret an electron microscopic (EM) case, you need some of basic tools

such as a working knowledge of normal. To describe a micrograph:

Begin by stating which tissue(s) is (are) present

Brief description of normal landmarks present

Describe pathologic changes

Have good vocabulary of EM terms - appendix I in the 2nd edition of cell pathology by

Cheville has a glossary of EM terms; this is a good starting point.

Morphologic diagnosis

Same rules apply as for LM cases

Be concise

Example: hepatocyte: degeneration, diffuse, moderate with intranuclear virions.

Diagnosis must be supported by morphologic description

Hepatocyte PCT Kidney


- 74 -

Below is an EM of a young plant cell: note the nucleus (N) surrounded by a double unit membrane;

the cell wall (CW) with its laminated (often amorphous) structure; mitochondria (M) with their

internal cristae, the vacuoles surrounded by a single membrane (tonoplast), and the endoplasmic

reticulum (ER). The dots throughout are ribosomes.

Nucleus: identified by its size, double unit membrane, and granular texture (due to chromatin).

Cell Wall: identified by its laminated or amorphous texture.

Mitochondria: identified by their size, by their double unit membrane, and by the enfoldings of the

inner membrane called cristae.

Plastids: Identified by their double unit membrane.

Leucoplasts can be identified by their absence of cristae or chromatin.Leucoplasts may have

amorphous starch grains, or crystalline protein.

Chloroplasts can be identified by their stacks of thallakoid membranes called grana.

Vacuole - Vacuole membrane: Vacuoles are surrounded by a single unit membrane. The texture

inside is clear - evidence of the absence of other cellular components.

Microbodies: Have a single unit membrane and are usually dense in appearance.

Golgi Bodies: In cross section appear as a stack of membrane-bound compartments resembling

a cross section of a stack of pancakes.

Endoplasmic Reticulum: Membranes that pervade the cell, seemingly not associated with any of

the structures listed above. If ribosomes are clustered along these membranes is called rough ER.

Ribosomes: dot-like structures often associated with endoplasmic reticulum.

Meristematic cells in roots parenchyma Chloroplast in Leaf Material from Glycine hispida (10000X)


- 75 -

Thicker ascospore walls (TEM) fungus TEM of phytoplasma colonizing the phloem of an infected stem.

Infectious Agent

A complete treatise of ultrastructural detail of infectious agents is beyond the scope of this

presentation. Generally speaking, it is easy to get carried away describing these organisms in any

detail, especially protozoa. It is better to describe the essentials, interpret and continue.

Viral

In describing viruses, describe size if a scale marker is present, shape, encapsulated or

not, appearance of nucleoid, and where virus is present (intranuclear, budding from cell

membranes/ walls, within er, extracellular, etc.).Some viruses are more easily identified

ultrastructurally than others:

Poxviruses- relatively large viruses (200-300 nm), replication in the cytosol unlike most

DNA viruses, substantial capsule and dumbbell-shaped nucleoid.

Adenoviruses- characteristic intranuclear paracrystalline array.

Herpesviruses- replication in nucleus where immature nucleocapsids are present, envelope

by budding through a membrane (often nuclear, sometimes er or plasma membrane).

Bacterial

Be familiar with general ultrastructural morphology of a bacterium. Knowing the species of

plant / animal, the tissue involved, and occasionally some other features, you can make an

educated guess as to the bacteria with which you are dealing. Describe size if a scale is given,

shape (coccus, rod, pleomorphic) and where bacteria are located (i.e. At microvillar tips, closely-

adhered to cell membrane / wall, intracytoplasmic and if so, within phagolysosome or free).

Pseudomonas putida under solute stress Pseudomonas putida with no stress Examples:


- 76 -

Bordetella- bacteria enmeshed in tracheal cilia; animal affected may be dog, turkey,

etc.Car bacillus- bacteria enmeshed in cilia of airway, but more likely in a rat.

These Helicobacter pylori Bacteria (formerly named Campylobacter) on human stomach

epithelial cells can cause certain types of stomach ulcers and gastritis. Peptic ulcers are holes or

sores in the stomach or duodenum and most are caused by this pathogen. With antibiotics, the

infection can be cured in a few weeks. TEM X40,000

Protozoal

Be familiar with some of the terminology used in describing protozoa, such as conoid,

micronemes and rhoptries. Note whether zoites are contained within a parasitophorous vacuole or

free in the cytoplasm. If in a bradycyst, is wall thick or thin? Some familiar examples include:

Giardia- elongated, attached along microvillar surface

Cryptosporidium- trophozoites attached to apical cell surface by feeder organelle, microvilli

are effaced only at the site of attachment. The trophozoites develop into schizonts.

Journals relating to Electron Microscopy

Journal of Electron Microscopy (Japanese)

Journal of Electron Microscopy Techniques

Journal of Microscopy

Biology of Cell (French)

Journal of Ultra-structural Pathology

Scanning Electron Microscopy

Ultramicroscopy

Developmental Dynamics

Anatomical Record

Journal of Cell Biology

Tissue and Cell

Electron Microscopy Reviews

Journal of Ultra structure and Molecular Structure Research

Cell and Tissue Research


- 77 -

Advances in Eco-Friendly Approaches in IPM

Ruchira Tiwari Department of Entomology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

What is Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is a system designed to provide long-term management

of pests, instead of temporarily eradicating them. It is the coordinated use of pest and

environmental information with available economic pest control methods to prevent unacceptable

levels of pest damage which is least hazardous to human being, property, and the environment.

Practicing IPM can reduce the use of chemical pesticides entering the environment and can save

money. IPM is based on taking preventive measures, monitoring the crop, assessing the pest

damage, and choosing appropriate measures. Many different tactics are used in IPM, including

cultural practices, biological control agents, chemical pesticides, pest-resistant varieties, physical

barriers etc.

IPM means a pest management system that in the context of the associate environment and the population dynamics of the pest species, utilizes all suitable techniques and methods in an compatible manner as possible to maintain the pest population at levels below those causing economically unacceptable damage or loss. FAO (1967).

Why Practice IPM?

Easy to adopt

Keep a balanced ecosystem

Considerably delays the development of resistance

Minimizes hazardous effects of pesticides considerably

More efficient and cheaper method of control

Promotes eco-friendly conditions.

IPM based on the following assessments

Thresholds levels: Thresholds are the levels of pest population at which pest management action

should be initiated/ undertaken to prevent the pests from causing an acceptable damage. The

threshold often is set at the level where the economic losses caused by pest damage would be

greater than the cost of controlling the pests which sometimes are called ‘Economic Thresholds’

(ET). Populations above these thresholds can reach the Economic Injury Level (EIL), where

they cause enough damage for the grower to lose money. At the economic injury level, the cost of


- 78 -

control is equal to the loss of yield or quality that would result otherwise.

Economic-Injury Level (EIL): (Stern et al., 1959): “The lowest population density of a pest that will cause economic damage; or the amount of pest injury which will justify the cost of control.”

Why eco-friendly approach is required?

Agriculture continued to change as per needs of the society leading to intensification in

crop production practices in late 1990s. This intensification has eventually encouraged pest

incidence coupled with more deliberate use of pesticides. The dark side of the indiscriminate use

of pesticides and the exponentially rising costs of pesticides necessitated limiting the use of

chemical control strategies and led to development of economically and ecologically sustainable

global agriculture through IPM. These insecticides posed real hazards, resulting into present state

of prevailing contamination of air, water, soil and food. Insecticides are toxic to humans and other

functional activities of ecosystem.

The eco-friendly approaches which are least disruptive to beneficial insect populations are

as follows:

(1) Cultural practices- It means adjustment of agronomic procedures to reduce pest abundance

or it is a manipulation of the environment to make it less favourable to insect pests. It needs the

basic studies of the life history and habits of the insects, its plants and animal hosts.

(a) Sanitation- It includes ploughing under infested plants after the harvest of the crop. It includes

destruction and pruning of twigs and branches infested with pests , gathering of plant debris which

harbor overwintering infestations or infections.

(b)Tillage- The cultivation of soil in and around crop plants to destroy numerous crop pests either

through mechanical injury or exposure to sunlight or predators e.g. larvae and pupae of cutworm,

gram pod borer, grass hopper etc.

(c)Alterations in sowing time- The early spring planted sugarcane crop is less attacked by early

shoot borer. In tarai region, if spring maize is planted before 15 February the attack of sorghum

shoot fly would be less. The early sowing of chick pea crop on 15th October was least infested

with H. armigera with maximum seed yield in comparison to crop sown on 24th December.(1) Early

sowing is practicable, cheap and environment friendly option to avoid pod borer infestation.

(d)Nutritional disorder-Proper dose of NPK make the crop healthy and less prone to insect and

disease attack.

(e)Improved storage structures – Plastic woven sacks for food grains packages were found

highly effective to control high moisture content.(2)

(f)Crop rotation Adopting of legume crop after a cereal crop reduces attack of white grub on

legumes.

To control nematode, Meloidogyne incognita in french bean, crop rotation like french bean-

rice- sesamum- french bean found effective in reducing the soil population, root galls and egg

masses of nematode and increase in the field of French bean.(3)


- 79 -

(g)Trap crops-Grow okra along with cotton to attract red cotton bug and jassids Grow pigeon pea

along with cotton to attract grey weevil Sorghum as trap crop in cotton for increasing paratising

efficiency of Trichogramma chilonis against bollworm when grown after 5 rows of cotton.(4)

Dhaincha ( Sesbenia bispinosa) was found economical when 4 lines of dhaincha was sown with

the host crop, soybean on the periphery of the field preferred by the females of girdle beetle. (5)

(h) Mixed croping- The sowing of Wheat+ gram+ mustard crops in mixed form found effective

against termite, gram caterpillar and aphid on their respective host plants.

(i)Intercropping Inter cropping of tomato crop with crucifer crops suppresses pest population of

H. armigera in tomato due to glocosinolate allelochemicals. Cotton with sesame showed control of

bollworm complex. Groundnut crop intercropped with pigeon pea showed lowest incidence as well

as % damage of Spilractia obliqua in ground nut. (6)

(j)Use of resistant plant varieties: Biotechnology (Genetically Modified (GM) or transgenic

crops)- It refers to the crops which express foreign genes isolated from any biological system. On

the basis of three factors which are responsible for the resistance mechanism in plants are :

Antibiosis, Non-preference and Tolerance for insect pest resistance, a number of genes have been

used for production of GM crops. Bt Cry proteins, tripsin inhibitors, Alpha amylase inhibitors,

potato proteinase inhibitor II (pinII), lectins, cholesterol oxidase, polyphenol oxidase have been

reported to provide insect pest resistance. Bt transgenic crops are potato, tomato, cotton Bt cotton

(bollguard) and tobacco American variety of grapes against Phylloxera, Winter majetin variety of

apple against wooly aphid were found effective.

(2) Mechanical practices-

These are the methods employing manual devices and machines and give immediate

results.

1) Hand picking- For large sized insects ( caterpillars, beetles bugs etc.)

2) Shaking and beating of branches-To dislodge the insects.

3) Banding- The application of sticky bands( alkathene bands) around the tree trunks to

prevent the movement of the insect pests e.g. for mealy bugs

4) Wire gauge screens- The stems or fruits could be surrounded by wire gauge screens

to prevent the attack of borers

5) Trench digging- This is good for trapping the grasshoppers and locusts which move in

bands and afterwards kill them with insecticides.

6) Trapping – The light traps, pheromone traps, baits are being used to lure the insect

pests to get early warning of increasing pest population. The adhesive traps for

catching alate (flying) mustard aphids were evaluated by making a glass jars painted

with mustard yellow colour and then smeared with transparent grease on its outer

surface to get the flying aphids stuck on the surface of the jar. (7)

(3)Biorational approaches-The utilization of naturally produced chemicals that affect insect

behavior, growth or reproduction and suppress the insect population without affecting the


- 80 -

environment. It includes biological control, use of sex pheromones in mating disruption, hormones

that is use to inhibit a biologically active system of living process like chitin synthase inhibitors,

mating disruption hormones and various types of baits used for mass trapping.

(a)Semiochemicals- These are the chemicals that are able to modify the behavior of the

perceiving organism at sub micro and nanogram level.

Pheromones – It is a chemical or a mixture of chemicals that is released to the exterior by an

organism and that causes one or more specific reactions in a receiving organism of the same

species.

Sex pheromones- These can be employed in IPM for three ways- monitoring / survey, mass

trapping and mating disruption of the pests. Insect population can be estimated and new areas

of infestation detected at very early stage. It is used to give warning regarding the outbreak of

the insect pests and determine economic threshold level to decide about the timing of insecticide

applications. An economical sex pheromone, polystyrene trap was fabricated having females of H.

armigera instead of synthetic septum for monitoring Helicoverpa armigera showed good results in

capturing more number of males in comparison to synthetic septum used.(8)

(b)Botanicals- The plant products and their active constituents played an important role in plant

disease control by combating growth and development of pathogens and inducing resistance in

host plants. Spore germination of Erysiphi pisi (powdery mildew of pea)was affected by 80% by

applying 500ppm of extract of ocimium sanctum, zingiber officinale rhizome and madhuca indica

leaves.(11). The 15% extract of datura, 20% of Azadirachta indica controls bacterial blight of rice

Xanthomonas oryzae var. oryzae. (12). Neem, tulsi and mint are antihelminthic in action. Plant

extracts such as leaf extracts at 10% concentration of Mint, tulsi ,abutilon indicum were found

effective against storage fungi

(Helminthosporium oryzae, Sarocladium oryzae Aspergillus niger, A. flavus) of paddy They

inhibited the fungal mycelia growth aswell as biomass production and spore germination of

pathogen. Garlic bulb extract (40%) water extract was checked against the growth of Aspergillus

niger and A. flavus( stored fungi) showed total inhibition of the growth of fungi. (13). Neem leaves,

neem seed kernel extract, neem oil were found very effective against the larvae of lepidopteran,

coleopteran and dipteran insects.(9,10).

(C) Insect growth regulators ( IGRs)

(1)Juvenile hormones- The juvenoids like methoprene, hydroprene, fenoxycarb, pyriproxyfen,and

antijuvenoids such as Precocene I and II, ecdysoids (anti moulting hormones and chitin synthetic

inhibitors ( Dimilin) are being employed for the control of insect pests. New insect growth

regulators like flufenoxuron 0.25% and Lufenuron (0.25% ) were found effective caused 80-85%

mortality of 3rd instar larvae of S. obliqua after 96 hrs of treatment. (14,15,) .Anti juvenile hormones

isolated from Plant Ageratum houstonianumis Precocene I and II induced precocious

metamorphosis in the milkweed bug.

(2)Moulting hormones(MHs) represented by ecdysone, ecdysterone and other ecdysteroids


- 81 -

secreted by prothoracic glands are responsible for normal moulting and growth and maturation of

insects. Phyto ecdysterone isolated from dried parts of Ajuga reptans strongly influenced the

metamorphosis of Epilachna beetle .

The exogenous application of this ecdysone at wrong time cause death of insects.

(3) Chitin synthesis inhibitor- A new class of insecticide is Bnzoyl Phenyl Urea (BPU)

analogues that is diflubenzuron, which is commercialized under the name of Dimilin. It inhibited the

last stage of formation of chitin and cent percent mortality was observed in 15 days old larvae of

Spilarctia oblique at 0.1 % concentration after 10 days of treatment. (16). Others are BAY SIR

8514 and IKI 7899, (chlorfluazuron), teflubenzuron, buprofezin. Plumbagin is a naturally occurring

chitin synthesis inhibitor present in the roots of medicinal shrub, Plumbago capensis.

(d)Biological control agents-

To save the natural enemies and pollinators it is required to have idea of the weakest stage

of insect which is transparent as well, is to be targeted for borers moth emergence and larval

hatching period is most preferred time for biocontrol. Most vulnerable stage of insect pest is

important. Apply insecticide after or before application of biocontrol agents.

(1) Microbials (Pathogens) – When microbial organisms or their products (toxins) are employed

for the control of insects, animals and plants in a particular area is referred as microbial control.

Principal groups of pathogens are —Bacteria Bt, NPV, fungi and nematodes

Bacteria- Entomogenous sporeforming bacteria are more promosing in insect control. The toxic

crystal producing bacteria is Bacillus thuriengensis which is marketed under different commercial

names dipel, centari, thuricide, biosporine, parasporine etc. like Bt kurstaki, Bt aizawai, Bt

thuriengiensis,. The bacteria causes septicemia (multiplication of the bacterial spores) in the

haemocoel of insects.

Viruses- The entomogenous viruses fall in two categories inclusion viruses and non-

inclusion viruses which produce inclusion bodies in the insect body. NPV

NucleoPolyhedrosis Viruses, Cytoplasmic Polyhedrosis Viruses (CPV) and Granulosis

Viruses (GV). NPV affects insect by producing polyhedral bodies which dissolves by the

alkaline gut of the insect midgut and cause death. The insect stops feeding becomes

sluggish and integument becomes fragile. The infected insect climbs to the higher positions

and the dead larvae usually hang by their prolegs (head downwards) and dry down to dark

brown and black

Fungi - Entomopathogenic fungi Beauveria bassiana and Mettarrhizium anisopliae causes

muscardine disease in insects. Biological control of Meliodogyne incognita by the

application of soil fungus, Paecilomyces lilacinus 2g/pot reduced the egg number by

forming mycilia around the eggs and breakdown the female by entering through their

vulva. Seed treatment of cowpea with fungus P. lilacinus together with the application of

organic matter ( leaves of Leuceana leucocephala) into the nematode infested soil one

week prior to the sowing was found to be more effective in reducing root knot nematodes


- 82 -

incidence and increasing the yield of cowpea .(17)

Nematodes- Infective juvenile of Steinernema carpocapsae and Heterorhabditis

transmits bacteria which are lethal to their hosts. They have a wide host range. Infective

juveniles can easily be cultured and stored for extended periods. Different nematode

formulations are available- liquid, granular and foam incorporated.

(2)Macrobial agents like predators and parasitoids are employed for the control of insects. The 4th instar

grub of Coccinella beetle is a potential predator of wheat aphid complex. The consumption of beetle

increases with increase in the age of the grubs.(18).

Biological control of weeds

A leaf beetle, Zygogramma bicolorata , introduced from Mexico for biocontrol of Parthenium weed.

Inoculative release of this beetle (100 pairs of adults/ acre) may be an important component of

Integrated Parthenium weed management.(19).

Animal originated products

Cow urine, cow dung, buffalo urine, biogas are in use, nowadays, to control the insect pest

infestation and diseases. Biogas (methane and carbondioxide) was successfully used in the

control of stored grain insect pests such as Rhizopertha dominica, Sitotroga cerealella, Corcyra

cephalonica infesting paddy which was carried out in 100 kg capacity of PVC bins over a period of

8 months. It was observed that it had no any adverse effect on seed germination of paddy.(20).

Cold and hot water extracts of urine of buffalo and bullock and milk of goat completely

inhibited mycelia growth of Macrophomina phaseolina causing dry rot in cotton. The cotton seed

germination was also found higher with vigorous growth of seedlings. It has been observed that

buffalo urine retained total toxicity after autoclaving when tested against tomato fusarial wilt

pathogen. (21)

Baffalo urine at 40% concentration (hot water extract, water extract and autoclaved) totally

inhibited the growth of Aspergillus spp. (13). Cow urine alone and in addition with Allium sativum

bulb powder, neem oil and tea leaves was found effective against snails, Lymnaea acuminata.(22).

Neem leaves and cow urine decoction was found promising to control S. Obliqua (23).

Cow urine against honeybee diseases— A novel approach (Dr. Ruchira Tiwari ) (24)

The effectiveness and feasibility of using an eco-friendly measure, cow urine were

assessed for the first time in preventing and management of bacterial infections of European foul

brood disease (EFB), a wide spread and serious menace of honeybee, Apis mellifera. Application

of cow urine (25 to 100%) as spray twice at weekly interval on infected combs and terramycin

sugar syrup (125 mg/l) as food and spray showed that cow urine at 75 and 100% concentrations

proved most effective and reduced disease infection to below detectable limit in 8-10 days,

respectively as against 20 days in terramycin syrup fed bees. Cow urine treated infected combs

not only showed rapid recovery in disease infection but also promotion of growth of brood wheares

in terramycin fed colonies the queen stops laying eggs for certain period. Re-occurrence of


- 83 -

disease in the cow urine treated combs was also not observed. Other beneficial effects of cow

urine on robbing, aggressiveness, egg laying and adult activities are discussed. The studies

revealed that cow urine can serve as a potential eco-friendly measure for management of EFB in

honeybees.

On the basis of above mentioned eco-friendly approaches, pre-planting discussions,

reviewing activities undertaken during the year and post harvest discussion and interpretation of

results with transfer of new technologies to the farmers and others related with plant protection

makes a sophisticated IPM programme.

REFERENCES

1. Chakravorty, S. and Nath, P. 2006. Effect of time of sowing on the incidence of pod borer, Helicoverpa armigera in chickpea. Indian Journal of Applied Entomology, 20,1 28-32.

2. Khanna, S.C.,Chaurasia, V. and Sundria, M.M. 2004. Suitability of plastic woven sacks for foodgrain packaging-moisture permeability. Annals of Plant Protection Sciences. 12, 1 210-211.

3. Ahmed, J.A. and Chaudhary, B.N. 2004. Management of Meloidogyne incognita in french bean through crop rotation. Annals of Plant Protection Sciences. 12,1, 118-120.

4. Khosa Jaspreet,Virk, J.S. and Brar, K.S. 2008. Role of sorghum as trap crop for increasing parasitizing efficiency of Trichogramma chiolnis against cotton bollworms. Journal of Insect Science. 21,1 , 79-83.

5. Chaudhary, H.R. and Girdhar Gopal. 2006 .Effect of Dhaincha sesbania bispinosa as a trap crop against girdle beetle in soybean. Indian Journal of Applied Entomology, 20,1 80-81.

6. Nath, P. and Singh, A.K. 2004. Effect of intercropping on the population of Bihar hairy caterpillar and leaf damage in groundnut. Annals of Plant Protection Sciences. 12,1, 32-36.

7. Prasad, S. K. 2004. Modified telescopic adhesive trap for catching alate mustard aphids. Annals of Plant Protection Sciences. 12,1 211-213.

8. Krishna Kant and Kanaujia, K.R. 2008. Low cost sex pheromone trap design for monitoring Helicoverpa armigera (Hubner). Journal of Insect Science. 21,1 61-66.

9. Mishra, P.K., Singh, D.P. and Srivastava, J.S. 2007. Bio-efficacy of neemazal, a product of azadirachtin against sclerotial development of Sclerotinia sclerotiorum and Sclerotinia rolfsii. Journal of Eco-friendly Agriculture, 2,2, 175-177.

10. Mallapur, C.P. and Lingappa, S. 2005. Management of chilli pests through indigenous materials. Karnataka Journal of Agricultural Sciences.18 (2): 389-392.

11. Maurya, S. Singh, D.P. Srivastava, J.S. and Singh, U.P. Effect of some plant extracts on pea powdery mildew ( Erysiphe pisi).2004. Annals of Plant Protection Sciences. 12,2, 296-300.

12. Meena, C. and Gopalakrishnan, Jayshree. 2004. Efficacy of plant extracts against bacterial blight ( Xanthomonas oryzae var. oryzae) of rice. Annals of Plant Protection Sciences. 12,2, 344-346

13. Wani, M.A. and Kurucheva,V. 2004. Effect of garlic bulb extract and buffalo urine on the growth of Aspergillus niger and Aspergillus flavus. Annals of Plant Protection Sciences, 12 (1), 221-222.


- 84 -

14. Ramesh Chander and Bhargava, M.C. 2005. Effect of methoprene on the reproductive potential of tobacco caterpillar, Spodoptera litura (Fabricius). Journal of Insect Science, 18 (2), 25-28.

15. Ramesh Chander, Bhargava, M.C and Choudhary, R.K. 2008. Effect of fenoxycarb on adults of Spodoptera litura.(Fabricius). Journal of Insect Science, 21 (1), 24-27.

16. Singh , Y.R. Singh, I.S. and Varatharajan, R. 2004. Bioefficacy of IGRs against caterpillars of Spilarctia obliqua. Annals of Plant Protection Sciences,12, (1), 198-201.

17. Hasan, N. 2004. Evaluation of native strain of Paecilomyces lilacinus against Meloidogyne incognita in cowpea followed by Lucerne. Annals of Plant Protection Sciences. 12,2, 121-124.

18. Soni, R. Deol, G.S. and Brar, K.S. 2005. Feeding potential of Coccinella septempunctata (Linn.) on wheat aphid complex in response to level/intensity of food. Journal of Insect Science, 21, (1) 90-92.

19. Kaur, P. and Shenhmar, M. 2006. Seasonal abundance of Zygogramma bicolorata on Parthenium hysterophorus in Punjab. Journal of Insect Science. 19, 129-133.

20. Yadav, S. and Mahla, J.C. 2005. Bioefficacy of carbondioxide concentrations and exposure periods against lesser grain borer, Rhyzopertha dominica, (Fab.) in stored wheat. Journal of Insect Science,18 (2) 84-89.

21. Raja, V. and Kurucheve, V. 1997. Antifungal properties of some animal products against Macrophomina phaseolina causing dry root rot of cotton. Plant Disease Research, 12,1 11-14.

22. Tripathi, R. Singh, V.K. and Singh, D.K. 2006. Freeze dried powder of cow urine reduces the viability of the snail, Lymnaea acuminata. Journal of Pest Science, 79,(3) 143-148.

23. Purwar, J.P. and Yadav, Sri Ram. 2004. Evaluation of age related response of Spilarctia obliqua to biorationals insecticides. Annals of Plant Protection Sciences. 12,2, 271-273.

24. Tiwari, R. and Mall, P. 2007. Efficacy of cow urine for management of European foulbrood disease of honey bee, Apis mellifera (L) at Pantnagar. Journal of Eco-friendly Agriculture, 2,2, 201-203.


- 85 -

Problems and Progress of Research on Alternaria Blight Resistance in Rapeseed-Mustard

R.P. Awasthi

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Alternaria blight (AB) is one of the most important diseases of rapeseed-mustard in India

(Kolte, 1985). Losses in yield attributed to this disease ranges from 10 - 70% depending on the

Brassica species cultivar planted and prevailing weather conditions in a crop season. In the

absence of transferable genetic sources of resistance to AB in commercially cultivated genotypes,

infection rate-reducing resistance to AB is a viable breeding strategy. But only limited studies have

been done to identify this type of resistance in rapeseed-mustard. To evaluate the effect of

different epidemiological components in relation to the rate of disease progress in some known

field resistance genotypes of Brassica species in comparison to susceptible genotypes. Attempts

were also made to determine biochemical components of most promising infection rate-reducing

resistance genotypes.

Significantly lower Area Under Disease Progress Curve (AUDPC) values and apparent

infection rates were observed in six genotypes viz., Brassica alba, B. campestris ssp rapifera, B.

carinata (PPSC 1), B. juncea cv ornamental rai, B. juncea cv PHR-1 and B. napus cv target as

compared to five other commonly cultivated susceptible genotypes. Number of spots on stem (per

15cm length) was found to be positively correlated with size of lesion (r=0.732), percent defoliation

(r=0.833), percent siliqua infection (r=0.939) and overall disease score (0.814). The number of

spots on stem at 15 days prior to maturity was the best component for evaluation of resistance to

disease under field conditions. Total chlorophyll and epicuticular wax content, presence of higher

amount of gallic acid, synergic acid and vanillic acid indicated the possibilities of their significant

role in reducing infection rate and increasing resistance of oilseed Brassicas.

Salient achievements for control of AB

I. Combination of boron @ 0.5% spray boric acid or zinc @ 0.2% through zine oxide

showed synergistic effect in efficacy of mancozeb brought improvement in AB disease

control by 16-20%.

II. Studies on epidemiological components showed that size of Alternaria spots was the

best single predictor for assessment of resistance/tolerance reaction to AB.

III. Brassica juncea genotypes (PAB-9511, PAB-9534, Divya Selection-2), B. napus

genotypes (EC-338997, BNS-4) and B. carinata (PBC-9221) have shown high degree

tolerance to AB.

IV. Divya mustard genotype is a useful donor parent for development of Alternaria tolerant

dwarf varieties of mustard.

V. Induced resistance through least aggressive pathotype of A. brassicae (D pathotype) is

proved to be effective in controlling the severe infection caused by virulent pathotype A.


- 86 -

brassicae (A. pathotype).

VI. Balanced fertilizer application N100 P40 K40 coupled with first spray of Ridomil-MZ @

0.25% at full flowering stage followed by second spray of Iprodione @ 0.2% or of

Mancozeb at pod development stage has been found effective in management of three

(Alternaria blight, white rust and downy mildew) important diseases of rapeseed-mustard.

VII. Epidemiology of Alternaria blight, white rust and downy mildew diseases has been

investigated in detail to understand the critical factors in development of diseases of

rapeseed-mustard with a view to developing disease management strategies including

choice of sowing of effective fungicides. Early October planting of the crop has been

found to remain free or least affected with Alternaria blight, downy mildew and white rust.

REFERENCE

1. Awasthi, R.P. and Kolte, S.J. (1989). Variability in Alternaria brassicae effecting rapeseed-mustard. Indian Phytopath. 42:275.

2. Conn, K.L., Tewari, J.P. and Awasthi, R.P. (1990). Disease assessment key for Alternaria black spot in rapeseed-mustard. Can Pl. Dis. Survey. 70:19-22.

3. Awasthi, R.P. and Kolte, S.J. (1994). Epidemiological factors in relation to development and prediction of Alternaria blight of rapeseed-mustard. Indian Phytopath. 47:395-399.

4. Kolte, S.J., Awasthi, R.P. and Vishwanath (1994). Divya mustard: A unique plant type and development traits in disease management. Eucarpia Cruciferae News L. 16: 128-129.

5. Vishwanath, Kolte, S.J., Singh, M.P. and Awasthi, R.P. (1999). Induction of resistance in mustard (Brassica juncea) against Alternaria black spot with an avirulent Alternaria brassicae isolate D. European J. Plant Pathol. (Netherlands). 105-217-220.

6. Nashaat, N.I. and Awasthi R.P. (1995). Evidence for differential resistance to Peronospora parasitica (downy mildew) in accessions of Brassica juncea (Mustard) at the cotyledon stage. J. Phytopathology. 143: 157-159.

7. Nashaat, N.I., Heran, A., Mitchell, S.E. and Awasthi, R.P. (1997). New genes for resistance to downy mildew (Peronospora parasitica) in oilseed rape (Brasica napus ssp. Oleifera). Plant Pathology 46 (6): 964-968.


- 87 -

Advancement in Seed Health Testing Techniques for Better Disease Management

Karuna Vishunavat

Department of Plant Pathology, GBPUA&T, Pantnagar- 263145(Uttarakhand)

Testing Seed for Pathogens

Collection, conservation and utilization of plant genetic resources and their global

distribution are essential components of international crop improvement programme. Inevitably,

the movement of germplasm involves a risk of accidentally introducing plant quarantine pests*

along with the host plant material; in particular, pathogens that are often symptom-less, such as

viruses, pose a special risk.

Relating to the phytosanitary safety of ever-increasing volume of germplasm exchanged

internationally, coupled with recent rapid advances in biotechnology, FAO and IBPGR launched a

collaborative programme for the safe and expeditious movement of germplasm, reflecting the

complementarily of their mandates with regard to the safe movement of germplasm.

The aim of the joint FAO/IBPGR programme is to generate a series of crop-specific

technical guidelines that provide relevant information on disease indexing and other procedures

that will help to ensure phytosanitary safety when germplasm is moved internationally

Objective of Seed health testing for seed borne Pathogens

Many phytosanitary regulations are implemented without fully understanding the economic

threat of a pathogen or a complete scientific analysis of a pathogen’s presence in that

country. This has led to confusing regulations, unnecessary tests or inspection

requirements and unjustified trade barriers.

Indexing seed for pathogen continues to be an important activity for regulation of

pathogens through phytosanitary certification and quarantine programs in domestic and

international seed trade.

To provide means to answer scientifically the problems encountered in the worldwide

movement of seed, an international movement has emerged to standardize seed health

tests and inspection practices for International Seed Trade.

The demand and pressure for indexing seed for pathogens is increasing to deliver healthy

seed to farmers and seed producers and to respect International Phytosanitary Regulations

(IPR) issues.

An increased product liability as well as competitive pressures within the seed industry,

seed indexing for seed borne pathogens has also become an increasingly important quality

trait in the market place, particularly in vegetable and field crops.

The seed industry has a twofold responsibility in the area of seed health:

Constraints while seed health testing

The reasons for the unavailability of adequate indexing methods can be roughly divided


- 88 -

into two categories:

1. In some cases reliable disease-indexing methods are not available because little is known

of the etiology of the diseases. Therefore, studies on etiology of those diseases have to be

encouraged for crops ranked as high priority by the IBPGR.

2. Where sufficient knowledge is available of the etiology, and reliable pathogen indexing

methods exist, they are not always practical because they are too lengthy or labour

intensive to be widely used.

Seed health testing procedures

Survey was carried out among relevant curators of germplasm collections, quarantine

specialists and plant pathologists to determine the current status of seed health testing

procedures and their application, particularly for priority crops.

Recent developments in serology and molecular biology provide the basic technology to

improve indexing methods for seed borne pathogens

Historical Background for Seed health testing for seed borne pathogens

The first International Rules for Seed health Testing was published by ISTA in 1928. This

document contained a special section on Sanitary Condition in which special attention was

recommended for Claviceps purpurea, Fusarium, Tilletia, and Ustilago hordei on cereals;

Ascochyta pisi on peas, Colletotrichum lindemuthanium on beans; and Botrytis,

Colletotrichum linicola, and Aureobasidum lini on flax.

Due to the frequent exchange of germplasm ,use of uniform testing procedures was

recommended by the first working group on seed borne diseases of the EPPO held in Paris

in 1954.

In subsequent PDC meetings organized in1957, 1958 and 1981, and subsequently ,an

efforts were made to standardized the techniques for indexing and detection of seed borne

pathogens in different crops.

International Seed Health Initiative

During the year 1993, in PDC Symposium in Ottawa, the need for guidelines for the

conduct of comparative testing in seed health was first addressed.The International Seed Health

Initiative-Vegetables (ISHI-Veg) started in 1993 as an initiative of the vegetable seed industry. In

1995, the PDC at its second Seed Health Symposium joined with the International Seed Health

Initiative of the vegetable seed industry to produce the Joint ISTA/ISHI Guidelines for Comparative

Testing of Methods for Detection of Seedborne Pathogens. International Seed Federation (ISF)

started two more ISHI’s (ISHI for herbage crops in 1997 and ISHI for field crops in 1999). Loosely

modelled on ISHI-Veg, these ISHI’s put more emphasis on quarantine pathogens and their impact

on the international seed trade. Working together with international group, the ISHIs assess,

develop and disseminate information on test protocols for economically important seed-borne

pathogens of vegetable, herbage and field crops. ISTA and ISHIs together are in practice of


- 89 -

validation and review the methods being developed or used for indexing seed borne pathogen

through Peer Review Committee.

Advances in Seed Testing Methodologies

Seed health testing has come a long way since the early days of Hiltner, Genter and Doyer, yet

the development, publication, and application of standardized test methods for indexing seeds for

pathogens have to meet the expectations of the seed industry and regulatory bodies

Testing Seed for Pathogens

Indexing seed for seed-borne pathogens is usually recovered by conventional agar plating,

blotter tests, seedling bioassay and microscopic observation or by serological techniques.

These methods too are multi-stage, time consuming, labour-intensive and subjective.

Bacterial seed borne pathogens have been detected by “growing on’ seed under controlled

conditions and noting the emergence of disease symptoms.

Direct isolation of pathogens has also been widely used and has the advantage that pure

cultures of the suspected pathogens can be identified and their pathogenicity subsequently is

confirmed

The traditional comparative test procedures are often slow and cumbersome requiring

extensive resources and substantial time. In the rapidly changing analytical world and faced

with limited resources it has become clear that an alternative status of validation which will

still provide the user with a significant level of reliability and reproducibility is needed.

Serological and molecular methods are therefore being looked upon as alternatives

Over the last 35 years, advances in techniques for the accurate and feasible detection of

many seed-borne pathogens have been developed .

These include incubation and identification (many seed-borne fungi), liquid plating assay

(seed-borne bacteria), Enzyme-Linked Immunosorbent Assay (seed-borne viruses) and

Polymerase Chain Reaction (PCR) technology.

Serological Methods

These methods are generally simple to perform, rapid and accurate when used, generally

to detect a number of bacterial and viral pathogens even if present in low level .

• Testing of lettuce seed for lettuce mosaic virus

• Indexing for Lettuce mosaic virus in lettuce seed a grow-out assay on several thousand

seedlings (30,000) used to be carried out .

• Later the test was changed to require a bioassay using an indicator host plant

Chenopodium quinoa

• Since 1983, a serological test, ELISA (enzyme-linked immunosorbent assay), has been

used. ELISA has proven to be not only more efficient but very sensitive in detecting low

levels of infections that could potentially threaten lettuce production.

• Some times serological methods in particular ELISA lack sensitivity and in certain cases


- 90 -

may give ambiguous results.

• Serological approaches, in certain cases, have been found to suffer a major draw back as

the method is unable to detect all strains of the pathogen and are therefore limited in their

use

Indirect Immuno-fluorescence Colony Staining Method

• The method has been developed for the detection of seed-borne bacterial pathogens and

is especially suitable for laboratories, seed companies, and quarantine stations which have

no facilities for conjugation of primary antiserum.

• The assay is easy to perform and results can be easily assessed in 4-5 days as compared

to 30-45 days in traditional methods.

• Choosing the right secondary conjugate is however, necessary to get best results in the

assay.

Molecular Methods

• PCR assays have high sensitivity and specificity and often require as little as 24 or 48

hours to complete. They are applicable to a wide range of pathogens and can be used to

separate closely related species.

• A costly and time consuming grow-out test on 10,000 seedlings was the only accepted

means for detecting this pathogen watermelon fruit blotch( Acidovorax avenae sub sp.

citrulli ).

• Recently a DNA-based polymerase chain reaction (PCR) has been developed as an

alternative or supportive method to the grow-out test.

• Certain laboratories are testing the D-Genos ready-to-use kits to detect Pseudomonas

savastanoi pv. phaseolicola and Xanthomonas axonopodis pv. phaseoli on bean seeds

and the data obtained are conclusive enough to allow the use of D-Genos kits for routine

testing as an alternative to standard procedures.

• In Xanthomonas campestris pv. campestris, PCR diagnostic test has the same level of

sensitivity of detecting low level infection in seed samples as the traditional pathology test,

and saves 2-3 weeks of time by avoiding the need to identify visually symptom

development in inoculated plants and offers the potential of a method for identifying pre-

symptomatic infection in plants.

• Advances in these technologies include the use of antibody-based assays (IFAS, IFC,

Affini-tips), DNA based assays (PCR, real-time PCR, BIO-PCR) and a combination of the

two (IMS-PCR).

• There are numerous ways of identifying sequence data that could be used for primer

design to detect a pathogen of interest. These include RAPDs, internal transcribed spacer

(ITS) regions of the ribosomal genes and specific gene sequences (Table 1).

• Primers can be designed to be extremely specific and amplify a single pathogen from other

very closely related species or more general to amplify a range of organisms


- 91 -

Future Strategy

With the globalization of agriculture, seed health testing is going to be mandatory in times

to come for seed quality control. This needs highly sensitive, foolproof and quick methods for

indexing seed borne pathogens. Immunodiagnostic and Molecular technologies which are highly

specific and sensitive test methods are yet to be simplified, standardized and commercialized for

indexing seed borne pathogens of concern. Time has come to have ready–to-use diagnostic test

kits which can be defined as a commercially packaged system of the principal or key components

of a seed health testing method used for indexing specific pathogen in a given host.


- 92 -

A Brief Tutorial on Use of Bioinformatics Tools for Plant Pathologist

S. Marla Department of Molecular Biology & Genetic Engineering, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Enoromous research has been conducted by taxonomists, field breeders, biochemists and

molecular biologists. This effort has generated valuated experimental data but remains isolated

and requires to be integrated at systems biology (full organismal) way. This task can be

accomplished by employing various Bioinformatics analysis tools as described below in the walk in

tutorial.

LAB. 1:

Objective: How to download gene/protein sequences From NCBI (EST Database).

1.) Go to NCBI Site search Tetep NBS-LRR (Pikh) gene.

2.) Search EST Data for BLAST gene AND Rice. 3.) Literature survey using pubmed related to

BLAST gene.

Go to Home Page of NCBI:

Search Nucleotide for Pikh Gene


- 93 -


- 94 -

LAB.2

BLAST (Basic Local Alignment Search Tool) is the heuristic search algorithm employed by

the programs blastp, blastn, blastx, tblastn, and tblastx; these programs ascribe significance to

their findings using the statistical methods of Karlin and Altschul (1990, 1993) with a few

enhancements.

The five BLAST programs described here perform the following tasks

blastp compares an amino acid query sequence against a protein sequence database;

blastn compares a nucleotide query sequence against a nucleotide sequence database;

blastx compares the six-frame conceptual translation products of a nucleotide query sequence

(both strands) against a protein sequence database;

tblastn compares a protein query sequence against a nucleotide sequence database

dynamically translated in all six reading frames (both strands).

tblastx compares the six-frame translations of a nucleotide query sequence against the six-

frame translations of a nucleotide sequence database.

Login to URL


- 95 -

http://www.ncbi.nlm.nih.gov/Education/BLASTinfo/information3.html

Go to ORF Finder Tool and check whether there are any other similar coded genes exist.

http://www.ncbi.nlm.nih.gov/Education/BLASTinfo/information3.html


- 96 -


- 97 -

Red & orange color lines shows areas of conserved parts in compared multiple gene sequences.


- 98 -

LAB.4

Download Protein Sequences of ABS72448, ABU55901 and ABV03556 and see their Domain

Position.


- 99 -

Plant Nematological Contributions to Phytopathology

Dr. K. N. Pathak Department of Nematology, Rjendra Agricultural University, Bihar, Pusa (Samastipur)- 848 125

Plant parasitic nematodes live most part of their lives either in soil, or in Plant parts, such

as roots, tubers, buds or seeds. As a rule they inhabit the root zone of plants. They continue to

threaten agricultural crops through out the world, particularly in tropical and subtropical regions.

For centuries man’s essential crop plants have been damaged by these microscopic organisms

that are hidden enemies of farmers. The degree of damage to a particular crop is influenced by the

crop and the cultivar, nematode species, level of soil infestation and environment. Severe damage

may result if higher infestation levels occur in soil where susceptible crops are grown. These

deleterious effects on plant growth results in low yields and poor quality crops such as vegetables,

pulses, cereals, potatoes, tobacco, cotton, groundnut, castor, banana, pine apple, citrus, coconut,

coffee are affected. Nematodes often cause decline or death of highly prized ornamentals.

The contributions of plant nematology to plant pathology is highlighted in this article by

providing key examples which cover wide range of studies in Nematology.

Historical

The recorded history of plant Nematology in the world goes back to 1734, when the ear-

cockle disease of wheat was proved to be caused by a species of nematodes, now called Anguina

tritici. By the mid 1800s scientists began to recognize more nematodes as the causal agents. Rev.

M.J. Berkeley (1855) discovered the root-knot nematode Meloidogyne spp. that occurs world wide

on many crops. Cyst forming nematodes were first observed by schacht (1959) and later

described by Schmidt (1971) as the sugarbeet nematode Heterodera schachtii.

In the early 1900s, the father of American Nematology Nathan, Angustus Cobb began

his nematological research. He described 1000 nematode species while developing tools and

apparatus that advanced the science. In 1907 Cobb joined the USDA and worked on pests of

cotton. In a secondary assignment, he inspected the 1909 Japanese gift of 2000 cherry trees

to the united states. He found the trees severely infected with nematodes and other pests and

had the trees destroyed. This situation motivated Cobb to develop procedures leading to the

Plant Quarantine Act of 1912. Cobb is among the first advocates of exclusion as a

management strategy for plant disease. Quarantine programs for nematodes have

demonstrated the importance of early detection and sanitation measure for disease control.

Cobbs insight and per severance led the USDA to establish the division of Nematology within

the Bureau of Plant Industry in 1915. He trained first generation of nematologists in America.

Cobb and his student G Steiner proposed that nematodes may be the primary cause of a plant

disease. It the early twentieth century, nematological laboratories were established world wide

viz., Canada (Barker), England (Goodey. T.), Netherlands (Schuuramans Stekhoven), Russia

(Filipjev) and USA (Cabb).


- 100 -

History of Indian Nematology dates back to 1901 when barber first reported the occurrence

of root-knot nematode of tea in south India. After that there were reports of several nematode

disease from different parts of the country, viz., ufra disease of Rice in East India caused by

Ditylenchus angustus, in 1913, white tip disease of rice by Aphelenchoides besseyi in 1936, Molya

disease of wheat and barley caused by Heterodera avenae in Sikar district of Rajasthan, in 1958,

and Potato cyst nematode in Nilgiri Hills of Tamilnadu in 1961. Realising the importance of

nematodes as limiting factors in Agricultural production and urgent need for intensification of

research in this field, the ICAR sanctioned the separate division of Nematology at IARI, New Delhi

in December 1966. Since then the Department of Nematology were opened in most of the SAUs in

the country.

The Nematological Explosion

Awareness of nematode problems was heightend in 1941 when the goldencyst nematode

was discovered in long Is land, New York. This nematode devastated the European and South

American Potato crops and a federal Quarantine which still exists, was put in to place. In 1950,

B.C. Chitwood and M.B. Chitwood added greately to nematode systematics with publication of

their work, entitled An Introduction to Nematology which served as primary text book, untill the

publication of G Thorne’s “Principles of Nematology” in 1961. Christie and Perry (1951)

demonstrated Pathogenicity of an ecto parasitic nematode Trichodorus sp. Recognition of

importance of nematode causal agents of plant disease continued to increase when the tobacco

cyst nematode and soybean cyst nematode were discovered in USA in 1951 and 1954

respectively. The science of nematology received a major catalyst with the discovery and use of

fumigant nematicides. The discovery of 1.3 dichloropropene (1, 3-D) and ethylene di bromide

(EDB) in 1940s not only provided a way to control nematodes but also added scientists in

demonstrating the impact of nematodes in field.

Plant Disease complexes

Many disease complexes involve plant parasitic nematodes as Pathogens. Nematodes

may serve as vectors, or may cause wounding that allow infection or predispose plants to other

pathogens. As early as 1892, Atkinson noticed that nematodes attacking cotton plants predispose

the plants to Fusarium wilt. Pitcher (1965) proposed several mechanisms of interaction between

nematodes and other soil borne diseases. These mechanism are further summerised by

Manzanilla-Lopez et al. (2004) indicating that nematodes (i) cause wounding that provides entry

point for pathogens that might have been present in the rhizosphere (ii) act as vectros of plant

pathogens such as plant viruses, (iii) act as “providers of necrotic infection courts” by leaching out

substrate from host plants that might serve as food base” for weaker pathogens, unable to infect

plant cells directly. (iv) “deter” plant diseases by grazing on fungal pathogens as in case of

Aphelenchus avenae. (v) break disease resistance impairing the host defence reactions by which

the healthy plants would otherwise repel pathogens.


- 101 -

Classical examples of Disease complexes include Potato early dying, Black shank-root-

knot complex of tobacco, Soyabean sudden death syndrame (SDS), Peach tree short life, Tundu

disease of wheat and barley, Annual rye grass toxicity (ARGT), Cauliflower disease of strawberry,

Twist disease of wheat etc.

Nematodes and viruses

In the first twenty five years of 20th century, several plant diseases were attributed to soil-

borne viruses with speculation that nematodes might be vectors. In 1958, Hewitt, Raski and

Goheen demonstrated transmission of grapevine fan leaf virus (GFLV) by Xiphinema index in vine

yards in California. Today of 4,000 described species of plant parasitic nematodes, only 30

species in two nematode families are known to be virus vectors. The longidoridae (Longidorus,

Paralongidorus, and Xiphinema) transmit repoviruses, and the Trichodoridae (Paratrichodorus and

Trichodorus) transmits tobra viruses.

Modeling and Precision Agriculture

Nematologists were early advocates of the concepts of critical point models for estimating

crop loss. Seen horst (1970) and Jones et al. (1967) pioneered in modelling nematode population

dynamics and were developing crop-response models to predict crop losses caused by

nematodes. Ferris (1984) and Mc Sorley and Phillips (1993) improved the models by including

stochastic or probabilistic statements. Perhaps one of the most successful uses of nematode

population modelling was the development of Integrated pest management (IPM) program for

nematode management in the Potato cyst nematodes (PCN) in Europe.

Control of Soil borne Diseases

Nematology has contributed greatly to our ability to control soil-borne diseases.

Biological control

Early scientists preferred biological control for soil-borne nematodes because nematode

antagonists were common in occurrence and performed well in Patridish experiments. Nematode

antagonists have been observed among a wide range of organisms including fungi, bacteria,

viruses, rickettseae, plants, protozoans, turbellarians, tardigrades, enchytracids, mites, insects and

even other nematodes. Among these fungal and bacterial antagonists have bean the most

extensively studied. Pioneers in the study of the fungal antagonists were mycologists, C.

Drechsler, R.P. Dolfuss, and G.L. Barron. These pioneers discovered, described and studied a

wide variety of fungi including those with adhesive hyphal nets or knobs and highly specialized

constricting sings or traps. A thorough review on biological control of nematodes by fungal

antagonists have been presented (Tribe 1980; Morgan-Jones and Rodriguez-Kabana 198; Stirling

1991; Sikora 1992, Kerry 1993; Kerryand Jaffee 1997; by Chen and Dickson 2004).

Suppressive soil

Gair et al (1969), Kerry and Crump (1982) initiated a new concept, deviating from the common

dogma of practicising crop rotation for nematode management. Instead, they suggested that nematode


- 102 -

suppressive soils are often associated with monoculture of a susceptible host. Kerry et al. (1982)

demonstrated that the main nematode-suppressing agents in these soils were Pochonia

chlamydosporium and Nematophthora gynophila. After 8 years of monoculture of nematode-

susceptible wheat cultivars population densities of CCN often declined to non detectable levels.

Pasteuria

Nematologists also work closely with bacteriologists. There are four nominal species of

Pasteuria that have been shown to attack Plant parasitic nematodes. Pasteuria penetrans from

RKN, Pastenria thornei from Pratylenchus spp., and Pasteuria nishizawae from Heterodera and

globodera, more recently a new species Candidatus pasteuria usage sp. nov, was found

parasitizing sting nematode on turfrass, Beloinolaimus longicandatus. Progress in being made to

wards developing a mass production of Pasteuria spp. In vitro.

Chemical control

The first soil disinfectant was carbon disulfide (CD). By 1933 CD was improved as liquid

controlling 90 per cent of nematodes in field (Guba 1932). At the same time, chloropicrin, and methyl

bromide was found to be an effective biocide. In 1943, W. carter discovered D-D, the first, 3-

dichloropropene containing product. It controlled mealybug wilt, and nematodes in pineapple. By the

1950s and 1960s methyl bromide and 1, 3-D dominated the fumigant nematicide market while the

carbonates and organophosphate chemical classes dominated the non fumigant market. The health

and environmental concerns in the late 1960s and early 1970s began to reduce the availability of

pesticides for soil borne disease control. DBCP was linked to male infertility in humans and later was

discovered in ground with depletion of ozone layer and its use was limited by 1992. All this has

prompted a new era of nematicide development towards biological based products.

Host Plant resistance

Host resistance to root-knot nematode was first recognized in 1889 by Neal who suggested

using selected orange-tree cultivars to control root-knot nematodes. Resistance to cyst nematodes

was identified in sugar beets at the same time. Trudgill (1991) clearly defined the differences

between tolerance (host response to nematodes) and resistance (nematode reproduction on the

host), and pointed out the importance of separating these two properties during nematode

resistance screening programs. Nematology led Plant Pathology in transgenic resistance

incorporating RKN resistance, the Mi-1 gene, from the wild Lycopersicon Peruvianum in to the

cultivated L. esculentum via embryo rescue.

Nematode Parasitism Genes

In recent years, a great deel of research has been conducted on the molecular biology of

parasitism genes of plant parasitic nematodes. A major contribution to the understanding of cyst

nematode parasitism occurred when cellulose degrading enzymes (-1, 4-endoglucanoses) from

H. glycines and G. rostochiensis were identified. The discovery that these genes have their

greatest similarity to microbial genes stimulated the first speculation in plant pathology that genes


- 103 -

for plant parasitism by nematodes may have been acquired by horizontal gene transfer.

Variability among Pathogen Populations

Nematologists have attempted to define population variation by identifying “races”,

“Pathotypes” and “biotypes” (Shaner et al 1992). Differences in host range were first noted among

populations of Ditylanchus dipsaci in the 1800s. Sasser differentiated population of root-knot

nematodes based upon host status.

Nematode as soil Health indicators

Yeates et al. 1993 synthesized a feeding habit profile for an extensive list of soil

nematodes, categorized nematodes in to algivores, bacterivores, fungivores, herbivores,

omnivores and carnivores. This served as the foundation of nematode community analysis.

Expanding the Boundary of Plant Pathology

Nematology is not limited to the study of plant parasitic nematodes, but includes studies of

free-living nematodes, EPN and animal parasitic nematodes, thus expanding the scope of plant

pathology to ecology, entomology, zoology and parasitology. Nematodes are found to be superb

model organisms for genetic studies.

Environmental bio indicators

lau et al. (1997) suggested introducing a bacterial feeder nematode Cruznema tripartitum,

in to soils being tested for toxicity. The survival and respiration rates of the nematodes provided a

useful bioassay of the presence and concentration level of toxins such as trichloroethylene,

toluene, and metam-sodium.

Conclusion

Study of plant nematology is young, and has evolved tremendously over the last 300 years

and has contributed significantly to the study of plant diseases. Nematology continues to strive in

its diverse contribution to plant pathology, and is expanding the boundaries of plant pathology, to

cell biology and genetic, environmental health studies and even in space science (Webster 1998).

More collaboration between nematologists with other scientists in plant pathology is needed to

develop sustainable agricultural systems.

REFERENCES

1. Barker, K.R. 1998. Introduction and synopsis of advancement in nematology. Pages 1-20 in : Plant and Nematode Interactions. K.R. Berker, G.A. Pederson, and G.L. Windham, eds. ASA, CSSA and SSSA, Madisor, WI.

2. Chen, S.Y. and Dickson, D.W. 2004. Biological control of nematodes by fungal antagonists. Page 979-1039 in : Nematology Advances and Perspective Vol. 2. Nematode Management and utilization. Z. X. Chen, S.Y. Chen and D.W. Dickson, eds. CABI Publishing, Beijing, China.

3. Wang, K.H.; Sipes, B.S.; Schmitt, D.P.; Mac Guidwin, A.E., Mckenry, M.; Bliss, T..; Kerry B.R.; and Costa, S. 2008. Plant Nematological contributions to Phytopathology. APS net Features.

4. Barker, K.R. 2004. A century of Plant nematology. Pages 1-51 in : Nematology Advances and Perspectives. Vol. 1. Nematode morphology Physiology and Ecology. Z. X. Chen. S.Y. Chen and D.W. Dickson eds. CABI Publishing, Beijing, China.


- 104 -

Status of Karnal Bunt of Wheat and its Management

R.C. Rai Department of Plant Pathology, Rajendra Agricultural University, Pusa, Bihar

Brief History and Distribution

Karnal bunt (Mundkur, 1943a), new bunt (Mitra, 1931) or partial bunt (Bedi et al., 1949) of

wheat was first observed by Mitra in April, 1930 in experimental seed material grown at the

Botanical Station, Karnal, Haryana and was reported by him in 1931. Mitra felt that the pathogen

was present much earlier and suspected that it might be one described from Layallpur (Pakistan)

in 1908 (Howard and Howard, 1909).

After the first report by Mitra in 1931, McRae reported Karnal bunt in a virulent form at

Karnal in 1934, and later the disease was found in Sind province of Pakistan in 1941 and the

erstwhile United Province and the Delhi State of India in 1942 (Mundkur, 1944). By 1943, it was

prevalent in Punjab and North West Frontier Provinces of Pakistan (Mundkur, 1943a). During

1944-45, the incidence was low (Dastur, 1946) but in 1948, serious damage by Karnal bunt was

observed in the Punjab and North-West Frontier Provinces of Pakistan (Bedi et al., 1949). Locke

and Watson (1955) reported that Karnal bunt was intercepted on plant materials imported by the

United States Department of Agriculture through the Washington inspection house, from

Afghanistan. These records emphasize that the disease was prevalent in the sub-continent since

long, infecting native wheat grown over Northwestern India but it never caused serious yield

reduction.

Till 1974-75 the Karnal bunt remained restricted to Punjab, Jammu and Kashmir and the

Tarai area of Uttar Pradesh (Singh et al., 1977). Since, there were no regulatory restrictions on the

movement of wheat in the country, the disease spread to more areas in North-western wheat belt.

Karnal bunt now has been recorded in the states of Punjab, Haryana, Jammu regions of J & K,

lower Himachal Pradesh, Uttar Pradesh, Delhi, Rajasthan and Bihar (Joshi et al., 1983). . In

addition, Singh et al. (1985a) reported presence of Karnal bunt also in West Bengal, Bihar,

Madhya Pradesh and Gujarat, covering eastern, central and western part of India. Rai et al.(1988)

reported an out break of Karnal bunt in eastern U.P. during 1986-87.

Most parts of the Madhya Pradesh, southern Rajasthan, Maharashtra, Orrisa, Assam,

Meghalaya, Karnataka, Andhra Pradesh, Tamil Nadu and Kerala are free from Karnal bunt as the

temperatures are higher in this region (Singh, 1986, Sharma et al., 1998).

The disease, besides present in Indian subcontinent including India, Pakistan, Afghanistan

and Nepal (Joshi et al., 1986; Singh et al., 1998) has also been recorded in Mexico (Duran and

Cromarty, 1977), Iraq (CMI, 1974) and Iran (Torabi and Jalalian, 1996). In 1996, Karnal bunt was

also reported from United States (Ykema et al., 1996) and from South Africa (Crous et al., 2000).

Karnal bunt infected wheat grains were intercepted in seed lots received from Lebanon, Syria,

Sweden and Turkey (Nath et al., 1981) but the interception of teliopsores does not confirm the


- 105 -

existence of the disease in these countries. Since, the disease is prevalent only in a few countries

around the world and the pathogen is soil and seed borne, the wheat importing countries have

imposed strict quarantine measures and insist on a zero tolerance limit on shipment. It is posing a

serious problem and interfering with free and fair wheat trade.

The disease has gained significant importance not only due to qualitative and quantitative

losses but also due to the fact that it poses a barrier in commercial seed trading at the national and

international markets because export of infected wheat grains would lead to the proliferation of

seed borne pathogens within and between regions, countries and continents.

Symptoms

The infection occurs at the flowering stage and the disease becomes evident when grains

have developed. Karnal bunt is visible on wheat grains, which are partially or completely converted

into black powdery masses enclosed by the pericarp (Mitra, 1931; Mundkur, 1943a, 1943b). In a

stool all the ear heads are not infected and in an ear all the grains are not bunted. In badly infected

spikelets, the glumes spread apart and quite often faIl off exposing the bunted grains which also

fall to the ground. Normally, the embryo tissues, except in very severe cases, is not destroyed.

Generally the infection spreads to the tissue along the groove of the grain but the endosperm

material lying along the groove of the grain remains uninfected. Frequently the grains are partially

infected. Freshly collected infected grains emit a foul smell, like rotten fish, due to production of

trimethylamine by the fungus (Mitra, 1935).

Losses

Yield

Karnal bunt is in existence since 1930 in the country but no serious economic repercussion

of the disease are evident. Munjal (1976) estimated a loss of 0.2% in yield annually in the states of

Punjab and Jammu region of J&K. Even during worst years of epidemic, the total damage to wheat

crop was only 0.2 to 0.5% of the total production (Joshi et al., 1983). Singh (1994) also suggested

0.3-0.5% loss in yield during the most severe years between 1982-89 particularly in Uttar Pradesh.

Hassan (1973) recorded 2-3% loss of grains from Pakistan. In Mexico, the total losses by each of

the states affected represented 2.1 %, 2.0% and 0.3% of wheat production in Sonora, Sinola and

South Baja California (Fuentes-Davila, 1998).

Munjal (1976) calculated the loss in yield by comparing weights of healthy and diseased

grain samples of wheat variety NP 720. The yield loss could be interpreted as yield x per cent.

infected grains x 1/3. According to Munjal, Karnal bunt covered about one third area under wheat

production in India and was responsible for an annual loss of around 40,000 metric tons of grain

per year.

Bedi et al. (1981) reported that the grain lots having 5 per cent disease incidence, common

in Punjab during 1978-79, were lighter in weight by 2.8 per cent. Depending upon the grade of

bunt infection, reduction in weight of infected grains ranged from 2.1 to 43.2 per cent (Bedi et al.,

1981) or 50 per cent (Bhat et al., 1980) compared with healthy ones. Rai and Singh (1985) found


- 106 -

that wheat cultivar UP 262 grains infected with low, medium, and high grades (extent of grain

portion converted into bunt sorus) of Karnal bunt infection were lighter in weight by 5.2, 20.0 and

51.6 per cent, respectively . This amounted to an average of 25.6 per cent or roughly 1/4 reduction

of weight per unit of per cent infected grains in a lot having all the three grades of infection in equal

proportion. Thus loss in yield could be interpreted as actual yield x per cent infected grains/l00 x

0.256.

Germination

Karnal bunt disease reduces both quality and quantity of wheat grains. A direct relationship

between intensity of Karnal bunt infection and reduction of wheat seed germination has been

established by several workers (Rai and Singh, 1978; Singh, 1980; Bedi and Meeta, 1981; Bedi et

al., 1981; Singh and Krishna, 1982; Bansal et al., 1984). Wheat kernels having only traces of

infection do not suffer any significant. deterioration in germination, but severely infected kernels

show considerable reduction in viability. Rai and Singh (1978) reported that the grain lots having

high and medium grades of Karnal bunt infection gave 58 and 72 per cent germination,

respectively, compared with 98 per cent germination in healthy grain lots. Those with low grade of

Karnal bunt infection gave 84 per cent germination. The infected grains, which retained their

viability, produced higher proportion of abnormal seedlings compared with the healthy grains.

However, Warham (1990) reported that infection had very little effect on seed viability, irrespective

of age of the seed and that infected seeds have a lower survival rate in storage compared with

healthy seed of the same seed lot. Apparently, Warham's grain samples had lower grades of

Karnal bunt infection compared with those of workers in India.

Quality

Karnal bunt pathogen not only reduces the weight and impairs viability of seeds, but also

causes deterioration of flour quality due to production of trimethylamine (Singh et al., 1983). This

fact is also important because flour industry suffers from quality and it posses restrictions in wheat

trade. Mehdi et al. (1973) examined the effect of bunts on the quality of "Chapaties" and attributed

that at 1 % infection of fresh seed lot, the palatability of "Chapaties" would be affected though very

little, but the "Chapaties" having 3% infection emits a fishy odour and are unpalatable. However, a

study undertaken at Ludhiana has shown that if the grains are washed and steeped, the samples

with 7-10% infection are acceptable for consumption (Sekhon et aI, 1980, 1981). It is possible that

washing reduces the quantity of trimethylamine which is a volatile substance. Products made out

of wheat lots with more than 5 per cent Karnal bunt infection, are not acceptable for human

consumption (Sekhon et al., 1980). In Mexico, grain lots rejected by milling industry due to greater

levels of Karnal bunt infection are used as animal feed (Brennan et al., 1990).

Chemical composition of Karnal bunt infected grains has been investigated. Rai (1983)

reported that moisture, dry matter and organic matter contents were not affected. The contents of

total sugars, reducing sugars, non-reducing sugars, starch and calcium decreased by 22-35 per

cent due to infection. However, there was increase in the contents of crude fIbre, ash, phenol,


- 107 -

lipid, water soluble protein, buffer soluble protein and phosphorus by 39.8, 31.5, 125.7, 43.2, 24.9,

21.6 and 18.3 per cent, respectively, due to Karnal bunt infection. The above average values for

increase or decrease were in accordance with the grades of Karnal bunt infection in the grain lots

with all the grains infected. Bhat et al. (1980) found that total ash and phosphorus content of

diseased grains increased, while the thiamine and lysine content decreased. Bedi et al. (1981)

found diseased grains have a greater percentage of crude fibre, crude protein and free amino

acids and a lower percentage of soluble sugars and starch compared with healthy grains. Sekhon

et al. (1980) found no appreciable effect on protein content of bunted grains, although arginine and

aspartic acid levels tended to increase in diseased grains.

Sekhon et al. (1980 ) reported that Karnal bunt infection greater than 5 per cent had no

effect on farinographic, water absorption and rheological properties of wheat flour or protein

content, sedimentation value, total sugars, loaf volume and specific volumes. However, the

diastatic activity was lowered and the spread factor increased. Also, crumb texture, crumb colour

and taste were severely affected. Medina (1985) found that the strength and tenacity of the bread

dough was decreased with increased levels of Karnal bunt infection.

No mycotoxins have been detected in Karnal bunt infected grains. Tests for ergot alkaloids

were also negative. Short term toxicity studies in rats by feeding them upto 50% bunt infected

grains over a period of 45 days did not show any adverse effect. Toxicological studies using

monkey as an experimental animal also showed that consumption of as high as 70% diseased

wheat grain in the diet was not toxic to animal (Bhat et aI, 1980, 1981). It is apparent from these

studies that Karnal bunt does not pose risk to human health and the effect of trimethylamine can

be overcome by peeling, debranning and washing of infected wheat lots before grinding.

Results of studies on toxicological aspects of bunted grains (Bhat et al., 1980; Bhat et aI.,

1983; Rai, 1983) indicated absence of acute toxicity to laboratory animals. Yet, the report by Rai et

al (1991) that feeding of Karnal bunt infected grains to albino rats was not safe as in such rats liver

and renal insufficiency was observed, calls for long term expert studies.

Pathogen

Mitra (1931) described Karnal bunt fungus as Tilletia indica but Mundkur (1944) transfered

it to genus Neovossia based on production of large number of non-fusing primary sporidia. Thus

the pathogen was renamed as N. indica. Krishna and Singh (1982a) also supported the view that

N. indica is closer to Neovossia than to Tilletia. However, Fisher (1953) did not agree with

Mundkur's view and again referred the pathogen as T. indica. The Commonwealth Mycological

Institute also retained the name T. indica because fragmentary appendages present on teliospores

and non-fusing sporidia are not the typical of N. indica as stressed upon by Mundkur, but are basic

characteristics of other Tilletia species also. The taxonomic issue still persists and in literature T.

indica is considered a synonym of N. indica.

The Host

Karnal bunt pathogen, Tilletia indica, infects bread wheat (Triticum aestivum L.), durum


- 108 -

wheat (Triticum turgidum L.) and triticale (X. Triticosecale Wittmack) (Mitra, 1931; Agarwal et al.,

1977). A number of accessions of different Aegilops spp. could also be infected under artificial

inoculation (Warham et al, 1986). Royer et al. (1986) and Royer (1988) reported that several

species of Aegilops, Bromus, Lolium, Oryzopsis and Triticum were susceptible to T. indica under

artificial inoculations. All cultivars of the aestivum group of wheats in India have been susceptible"

to the disease, although they differ in the degree of susceptibility (Agarwal et al., 1976; Gautam et

al., 1977; Gill et al., 1981).

Inoculation Techniques

At present, the following inoculation techniques are available: 1) the boot inoculation

technique - injection of a suspension of secondary sporidia into the boot of the wheat plant at awn

emergence using a hypodermic syringe (2) the spray inoculation technique-a suspension of

secondary sporidia is sprayed onto the wheat spike at various stages between heading and

anthesis (Chona et al., 1961; Aujla et al., 1980; Singh and Krishna, 1982; Warham, 1984).

The boot inoculation technique is the most reliable, giving up to 100% infection on

susceptible varieties, but it is a severe method that screens for physiological resistance only

(Warham, 1984, 1986). Although, boot inoculation technique has been an efficient field screening

method in India and Mexico, it knocks down useful field resistances. The boot inoculation

technique knocks down morphological resistance and screens for physiological resistance only.

The spray inoculation technique more closely mimics field infection and screens for

morphological, and to a lesser extent, physiological resistance. However, this method is

considered unsuitable as a field screening method in dry areas, as it requires high humidity to

ensure infection. In the greenhouse, where conditions can be conrolled, it provides a rapid,

efficient means of screening (Warham, 1986).

Molecular Detection

The detection of Karnal bunt pathogen (Tilletia indica) is based primarily on the presence of

teliospores on wheat seeds. However, accurate and reliable identification of T. indica teliospores

by spore morphology alone is not always possible. The morphologically similar teliospores of the

widely distributed rice Kernel smut fungus Tilletia barclayana (Bref.) Sacco & Syd. can be found as

contaminant on harvested or stored wheat and misidentified as T. indica. Therefore, molecular

methods based on DNA analysis have provided very useful information for species identification. A

species specific marker for T. indica has been identified using a PCR based method and

mitochondrial DNA as a probe (Ferreira et al., 1996, Smith et al., 1996). The primer pair Ti1/ Ti4

amplified a 2.3 kb fragment from total DNA of T. indica isolates while it did not produce any bands

with other smut fungi (Ferreira et al., 1996). Molecular analysis of different species of Tilletia has

also been carried out using random amplified polymorphic DNA (RAPD) marker (Bonde et al.,

1996; Shi et al., 1996; David and Darrell, 1996). Molecular analysis using repetitive elements has

been used to study genetic diversity among the isolates of T. indica (Datta et al., 2000), which will

aid in detecting new virulences and checking the new resistant sources in the host germplasm.


- 109 -

Molecular methods such as (PCR-RFLP) analysis of the ITS region of rDNA is another important

method used to differentiate species of Tilletia such as T. indica. T. barclayana, T. walkeri, T.

controversa, T. goloskokovii, T. laevis, T. tritici and T. fusca (Mc Donald et al., 2000). Using these

molecular methods, the presence of pathogen in the form of teliospores in the infested grains can

be reliably detected at infestation levels of five teliospores per 50g grain sample (Smith et al.,

1996)

Epidemiology

Karnal bunt is a soil, seed and air borne disease. Teliospores of T. indica in the seed get

into the soil at the time of harvesting, threshing or winnowing (Mitra, 1937). The spores remain

viable for a number of years in the soil lying 15 to 25 cm deep (Dhiman and Bedi, 1989).

Teliospores buried deeply in soil losses their viability, due to low availability of oxygen and

moisture (Rattan and Aujla, 1990; Siddhartha, 1992). Under irrigated soil, the spores show

significantly higher germination resulting in higher infection (Aggarwal et al., 1989: Gill et al.,

1993). Warham and Flores (1988) noted that more than 70% of non-irrigated farms were free of

Karnal bunt. Irrigation provides the much needed moisture for teliospores to germinate. Singh and

Srivastava (1997) noted that chances of survival of teliospores are more under the irrigated

conditions of rice wheat cropping system. The spores surviving in rice field are brought to the soil

surface from different depths and serve as source of primary inoculum for fresh infection of Karnal

bunt pathogen. It is because of the favourabte high moisture conditions in rice-wheat cropping

system, the level of Karnal bunt is generally more in North-western region than dry central and

peninsular India.

The dormant dark coloured thick walled teliospoes tolerate harsh, warm and dry summer

conditions during post-harvest period. The spores germinate from the middle of February to middle

of March depending upon suitable meteorological conditions (Bedi et al., 1949). Krishna and Singh

(1982) found that for teliospores germination optimum temperature range is between 20-25°C.

Earlier, it was believed that the teliospores germinate in soil and produce 110-185 primary sickle

shaped sporidia which are the infective entities. But now it has been established that on teliospore

germination, two types of sporidia namely allantoid and filiform are produced and they play distinct

role (Dhaliwal and Singh, 1988). The filiform sporidia serve as the reproductive bodies to raise

allantoid sporidia in successive germinations whereas, the banana shaped allantoid sporidia are

infective bodies (Dhaliwal, 1989; Dhaliwal and Singh, 1989). Nagarajan (1991) hypothesized that

the flag leaf intercepts the allantoid sporidia and facilitate the run down of water droplets with

allantoid sporidia into the leaf sheath along with rain. Subsequently, it was shown that the flag leaf

sheath acts as the congenial site for allantoid sporidia multiplication and inoculum build-up (Kumar

and Nagarajan, 1998). The awn emergence stage corresponding to Z 49 (Zadoks et al., 1974) is

the most vulnerable stage for the rain promoted inoculum run down. The establishment of the

pathogen is highly dependent on suitable weather conditions. The infection gets established very

well if the maximum temperature is in the range of 19-23°C and minimum 8-10°C, followed by high


- 110 -

humidity by intermittent rains (Joshi et al., 1981). Aujla et al. (1990) clarified that if soil remains

moist even for a period of 7-10 days during February and 1st week of March, high sporulation

takes place and sporidia cause infection in emerging ear during this period, hence abundant rains

coinciding with anthesis stage favour disease development. These meteorological conditions

prevail in the North-western region but absent in central India-Madhya Pradesh and Rajasthan

(Singh and Srivastava, 2001) and thereby restricted the development of Karnal bunt. On the other

hand, the mid and higher altitudes of Himalayas, where snowfall occurs every year, Karnal bunt

can not establish and survive. In this region, the snowing and thawing reduce the viability of

teliospores in soil. Possibly snowing also induces cold dormancy and therefore, the chilled spores

require more energy to germinate. These spells of snow can delay the process of teliospore

germination, sporidial proliferation and ultimately result in disease escape.

Certification

In India, visual inspection of seed for apparent symptom of Karnal bunt infection is applied

for seed certification. The tolerance limits (certification standards) of Karnal bunt infection are 0.1%

and 0.25% for foundation and certified seed, respectively (Tunwar and Singh, 1988). However,

Agarwal and Verma (1979) and Rai and Singh (1985) suggested consideration of also non-bunted

seeds carrying surface-borne teliospores and spore load of the grain lots, respectively, in seed

certification procedures.

Management Strategies

Successful management of Karnal bunt, which is soil, seed, and air-borne, would depend

on our understanding of host resistance, regulatory measures, cultural practices, biosuppression

techniques, and chemical measures and their integration into an appropriate package of practices.

Resistant cultivars of wheat

Due to the complex nature of the Karnal bunt pathogen, use of resistant cultivars is the

most important approach to manage it. However, at present no cultivar of the aestivum group of

wheats has been found immune to Karnal bunt (Joshi et al., 1970; Agarwal et al., 1976; Gill et al.,

1981; Hoffmann, 1983). It appears that the commercial wheat varieties cultivated in India since the

first report of Karnal bunt in 1931 have been susceptible to the disease, although they do differ in

the degree of susceptibility (Agarwal et al., 1976; Gautam et al., 1977; Singh et al., 1980; Bedi,

1980,; Rai and Singh, 1989). Joshi et al. (1980) surveyed field incidence of Karnal bunt and. found

that Sonalika, the chief commercial cultivar in the entire wheat growing tract, had much less

incidence than Arjun (HD 2009), WG 357, WG 377, WL 711 and UP 262. The higher average

infection on Sonalika in Punjab, Himachal Pradesh and Jammu and Kashmir compared to that in

UP was attributed to multiplication of inoculum due to extensive cultivation of susceptible varieties

in these states. In UP, extensive cultivation of Sonalika did not permit the build up of inoculum and

possibly that accounted for low incidence of the disease in UP (Joshi et al., 1980). The wheat

cultivars, Sonalika (S-308) and PV-18 showed significantly less infection in Punjab compared to

other commonly grown cultivars, WL 711, WG 357, WG 377 and HD 2009 (Bedi, 1980). In UP,


- 111 -

wheat varieties HD 2285, HD 2281, UP 368, UP 2113 and UP 2121 showed only traces of

infection, while HD 2009, WL 711, Janak, Shekhar, Malviya-55, UP 262, HP 1102, HD 2204, UP

2003, HD 2329 and RR-21 showed high to moderate susceptibility in the field (Singh et al., 1988a;

Singh and Singh, 1988; Rai and Singh, 1989).

Gautam et al. (1977) noted the reaction of 96 promising wheat lines in the field conditions

and found 32 lines with zero infection, 10 with less than 1%, 38 with 1-5%, and the remaining 16

lines with over 5% infection. Aujla et al. (1980) screened 286 genotypes with the boot inoculation

technique and found 10 lines with only 1-5% infection.

Warham et al. (1986) screened 86 accessions of 21 Aegilops species against Karnal bunt

under greenhouse conditions using the boot inoculation technique and found that all accessions of

Ae. biunciales, Ae. coll!mnaris, Ae. crassa, Ae. juvenalis, Ae. ovata and Ae. speltoides and one or

more accessions of 13 other Ae. species were resistant to Karnal bunt.

CIMMYT (1989, 1992) has identified numerous resistant lines in bread wheat, durum

wheat, and triticale in the Karnal bunt screening nursery. Singh et al.(2003) reported that out of 66

entries tested, 18 namely HD 29, HD 30, HD 2385, RAJ 2296, WL 1786, WL 6975, WL 7247, HW

502, PBW 34, PBW 225, W 285, W 382, W 388, W 485, DWL 5010, ND 589, ND 602 and HP

1531 were resistant lines,. PBW 34 and PBW 225 are released varieties. Nineteen lines received

from CIMMYT were also resistant to Karnal bunt. HD 29 and HD 30 have already been registered

by the National Bureau of Plant Genetic Resources, New Delhi, as INGR 99012 and 99011,

respectively. Six Karnal bunt-free ('KBRL 10', 'KBRL 13', 'KBRL 15', 'KBRL 18', 'KBRL 22', 'KBRL

24') and 3 high-yielding Karnal bunt-resistant wheats ('W 7952', 'W 8086', 'W 8618') have been

developed by pyramiding of Karnal bunt-resistant genes and pedigree method of breeding

respectively( Sharma et al..2001). 'PDW 274' showed high degree of resistance (Mahal et al.,

2003). KB-resistant lines with plant yield comparable to PBW 343 have been recovered.( Sharma

et al., 2003). A number of resistant lines/ varieties have been identified (Sharma et al., 2004).

Gartan et al., 2004 reported that the genotypes HS450, HS455, HPW232, VL861, PW731,

PW733, PW738 and PW739 manifested multiple resistance against yellow and brown rusts,

powdery mildew and Karnal bunt.

Seed treatments and fungicide sprays

Mitra (1935, 1937) found that seed treatment with Uspulun (methoxyethyl mercuric

chloride), copper carbonate, Ceresan (ethylmercury chloride), formalin, Agrosan GN

(phenylmercury acetate), Hortisan A and sulphur reduced infection but did not check the disease

altogether. Munjal (1975a) studied the effect of different fungicidal treatments on teliospore

germination and found Ceresan and Nl Ceresan to be the most inhibitory. However, the fungicide

treatment did not result in cent per cent control of the seed-borne inoculum. Rai and Singh (1979)

tested Brestan (triphenyltin acetate), Brestanol (triphenyl tin chloride), Du-Ter (triphenyltin

hydroxide), Plantvax (oxycarboxin), and Indar (butrizol) as slurry seed treatments and found them

highly inhibitory to germination of teliospores but none was able to eradicate the seed-borne


- 112 -

inoculum completely. Mitra (1935) believed the reason for non-eradication of seed-borne

teliospores to be that the spores in point infections are well protected by the pericarp and therefore

the fungicide can not reach the teliospores.

According to Fuentes et al. (1983) and Warham and Prescott (1984), the most effective

fungicides, which effectively inhibited teliospore germination, were Panogen (methoxyethyl

mercury acetate), Terrazan (pentachloronitrobenzene) and mercurials and the heavy metals

(copper, zinc, and manganese). Singh et al.(2002) reported that Raxil 2DS reduced teliospore

germination by 89.60 to 100%.

Prevention of floral infection by sporidia of T. indica by application of fungicides as foliar

sprays is an important approach to control the disease. In multilocation field trials over several

crop seasons in UP, Singh and Prasad (1980) and Singh et al. (1985) found that Karnal bunt

infection of wheat flowers could be prevented by a spray of either mancozeb, carbendazim or

fentin hydroxide at the early heading stage before flowering of the crop. They also found benomyl,

oxycarboxin, and triadimefon to be next in order of effectiveness. Bitertanol, which they tested for

one year only, proved highly effective against Karnal bunt in the field. In another field study, spray

of bitertanol (Baycor) at heading stage proved significantly superior to triadimenol (Baytan),

triadimefon (Bayleton), caIboxin (Vitavax), fenfuram (panoram) and Furavax in controlling Karnal

bunt (Singh et al., 1988b). Singh et al. (1988b), Aujla et al. (1989) , Aujla and Sharma (1990) ,

Sharma and Basandrai(2004) and many workers have found single spray of propiconazole (Tilt) to

be highly effective against Karnal bunt. Benomyl (Benlate) and carbendazim (Bavistin and

Agrozim) are also effective (Aujla and Sharma, 1990). Folicur at 0.20%, Contaf at 0.10%, Tilt at

0.10% and 100 g a.i. thifluzamide/ha resulted in more than 90% karnal bunt control, while Folicur

at 0.40% and 0.80%, and Contaf at 0.20% resulted in 100% bunt control (Sharma et al., 2005).

Sharma and Sharma(2004) reported that Controll is a promising fungicide against karnal bunt and

can be used as an alternative to recommended fungicides( Tilt).

Cultural practices

Singh and Prasad (1978) observed that the incidence of Karnal bunt gradually increased

with delay in sowing. Aujla et al. (1981) also reported that Karnal bunt incidence increased sharply

with delay in sowing time. However, Gill et al. (1981) did not consider adjustment of sowing date a

good practical solution, since northwest India has certain years with sharp weather fluctuations at

anthesis.

Bedi et al. (1949) reported that the disease incidence was as high as 30% in heavily

manured, irrigated clay soils where the crop had lodged, compared with only 2% in unirrigated

fields with little or no manure or no crop lodging. Nitrogen doses greater than 80 kg/ha have been

shown to increase the disease (Aujla et al., 1981). Apparently high fertility irrigated conditions,

which favour high productivity of wheat crop, also favour Karnal bunt spread in the field. Whether

balanced fertilization, including potash and phosphorus and micro nutrients, would help reduce the

disease has not been investigated.


- 113 -

Mitra (1937) strongly recommended crop rotation in view of the possibility of infection from

soil. However, the survival of T indica teliospores from two to four years in the soil and air-borne

infection process of the fungus (Singh and Mathur,1953; Munjal, 1975; Krishna and Singh, 1982c)

would limit the benefits of crop rotation.

Zero Tillage has shown a reduced incidence of KB in comparison to the furrow irrigated

raise bed system and conventional till systems. If ZT is followed for a period of a few years, it may

help in reducing the effective soil inoculum and reducing the disease incidence over time.

Regulatory measures

The Government of Mexico imposed legal restrictions on growing of bread wheats, durum

wheat, and triticales depending on Karnal bunt incidence in 2 km2 blocks in the previous year to

control development of the disease within the Yaqui valley. Where there was less than 1 % Karnal

bunt infection in the previous year, the farmer could plant the crop he desired. If there was 1-2%

infection the farmer could plant only durum wheats and triticales; and if there was more than 2%

infection, only triticales could be planted (Delgado, 1984; Lira, 1984).

Agriculture Canada has maintained a zero tolerance for the pathogen (Martin, 1986).

Quarantine measures are in force to prevent introduction of the pathogen to non-infested regions

(Anonymous, 1991).

Biosuppression techniques

Antagonism of Neovossia indica by isolates of Aspergillus spp., Bacillus spp. and

Streptomyces spp., isolated from field soils, was reported by Misra and Singh( 1988).Aspergillus

isolates caused browning, lysis and disintegration of N. indica mycelium and overgrew it. Species

of Bacillus & Streptomyces caused growth inhibition, browning, deformation, lysis and

fragmentation of N. indica mycelium. All the three groups of antagonists induced formation of

higher number of sporidia at initial stages of interaction, which was followed by complete lysis and

disintegration of the sporidia. Whether biosuppression of the Karnal bunt pathogen by the above

antagonistic microorganisms and others like Trichoderma viride and Gliocladium virens

(unpublished) in the field conditions would become a part of the management procedures will

require more research.

Conclusion

Karnal bunt spreads through the seed, soil and air and therefore, difficult to manage. Such

interactions reveal that an integrated approach for tackling Karnal bunt is the most ideal. Singh et

al. (1979) suggested a comprehensive package to manage the disease through avoidance of

highly susceptible cultivars, excessive nitrogenous fertilizers, irrigation at flowering time and late

planting in endemic areas. The live soil mulch or growing a companion crop of chickpea along with

wheat was found to reduce the incidence of Karnal bunt significantly (Singh et al., 1992).

Solarization during summer using the black or transparent plastic film has also been noted to

reduce the disease incidence and severity (Singh, 1994). Under present conditions of intensive

and extensive cultivation of wheat, these eradication practices do not appear feasible. Seed borne


- 114 -

inoculum can be reduced through fungicidal seed treatment. Though seed dressing fungicides

may reduce seed borne inoculum of T. indica, for prevention of floral infection we need to spray

systemic fungicides at early heading stage before flowering. Bio control agent may serve as an

useful component of IDM.

REFERENCES

1. Agarwal, V.K. and H.S. Verma (1979). Karnal bunt of wheat- a view on seed certification standards. Seed Technology News 9: 1-2.

2. - Agarwal, V.K., A. Singh and H.S. Verma. (1976). Outbreak of Karnal bunt of wheat. FAO Plant Prot. Bull. 24 : 99-100.

3. - Agarwal, V.K., H.S. Verma and R.K. Khetarpal (1977). Occurrence of partial bunt in Triticale. FAO Plant Prot. Bull. 25 : 210-211.

4. Aggarwal, R., L.M. Joshi and D.V. Singh (1989). Inoculum production in relation to varieties in Karnal bunt disease of wheat. Indian Phytopath. 42: 569-571.

5. Amer, G.A.M. (1995). Biocontrol of Karnal Bunt of Wheat. Ph.D. Thesis, Division of Mycology and Plant Pathology, IARI, New Delhi.Anonymous. (1991). Quarantine procedure No. 37. Tilletia indica. EPPO .Bulletin 21 : 265-266.

6. - Aujla, S.S. and I. Sharma (1990). Evaluation of fungicides against Karnal bunt disease of wheat. J. Res. (PAU) 27: 434-436.

7. - Aujla, S.S., A.S. Grewal, K..S. Gill and I. Sharma(1980). A screening technique for Karnal bunt disease of wheat. Crop Improvement. 7 : 145-146.

8. Aujla, S.S., I. Sharma and K.S. Gill (1990). Sources of resistance in wheat to Karnal bunt. Indian Phytopath. 43: 91-93.

9. - Aujla, S.S., I. Sharma, P. Singh, G. Singh, H.S. Dhaliwal and K.S. Gill (1989). Propiconazolea promising fungicide against Karnal bunt of wheat. Pesticides 13 : 35-38.

10. Aujla, S.S., K.S. Gill, Y.R. Sharma, D. Singh and G.S. Nanda (1981). Effect of date of sowing and level of nitrogen on the incidence of Karnal bunt of wheat. Indian J. Ecol. 8 : 175-179.

11. Bansal, R., D.V. Singh and L.M. Joshi (1984). Effect of Karnal bunt pathogen (Neovossia indica (Mitra) Mundkur) on weight and viability of wheat seed. Indian J. Agric. Sci. 54 : 663-666.

12. Bedi, K.S., M.R. Sikka and B.B. Mundkur (1949). Transmission of wheat bunt due to Neovossia indica (Mitra) Mundkur. Indian Phytopath. 2: 2026.

13. Bedi, P.S. and M. Meeta (1981). Effect of Karnal bunt on weight and germination of wheat grains and subsequent metabolism of seedlings. Indian Phytopath. 34 : 114.

14. Bedi, P.S., M. Meeta and J.S. Dhiman (1981). Effect of Karnal bunt of wheat on weight and quality of grains. Indian Phytopath. 34 : 330.333.

15. Bhat, R V., B. Rao, D.N. Roy, M. Vijayaraghavan and P.G. Tulpule (1983). Toxicological evaluation of Karnal bunt of wheat. Journal of Food Safety 5 : 105-111.

16. Bhat, R.V., B. Rao, D.N. Roy, M. Vijayaraghavan and P.G. Tulpule (1981). Toxicological evaluation of Karnal Bunt in monkeys: a report, Bull. Food and Drug Toxicological Research Centre, JamiaOsmania, Hyderabad, India, pp. 5.

17. Bhat, R.V., V.G. Deosthale, D.N. Roy, M. Vijayaraghvan and P.G. Tulpule (1980). Nutritional and toxicological evaluation of Karnal bunt affected wheat. Indian J. Expert. BioI. 18: 1333-1335.

18. Bonde, M.R., G.L. Peterson, G. Fuentes-Davila, S.S. Aujla, G.S. Nanda and J.G. Phillips (1996). Comparison of the virulences of isolates of Tilletia indica, causal agent of Karnal bunt of wheat, from India, Pakistan and Mexico. Plant Dis. 80: 1071-1074.

19. Bonde, M.R., G.L. Peterson, N.W. Schaad and J.L. Smilanick (1997). Karnal bunt of wheat. Plant Dis. 81: 1370-11377.


- 115 -

20. Brennan, J.P., E.J. Warham, J. Hernandez, D. Byerlee and F. Coronel (1990). Economic Losses from Karnal Bunt of Wheat in Mexico. CIMMYT Economics Working Paper 90/02. Mexico.

21. Chona, B.L., R.L. Munjal and K.L. Adlakha. (1961) A method for screening wheat plants for resistance to Neovossia indica. Indian Phytopath. 14 : 99-10 1.

22. CIMMYT. (1989). CIMMYT 1988 Annual Report (International Maize and Wheat Improvement Center) : Delivering Diversity, Mexico D.F., CIMMYT

23. CIMMYT. (1992). CIMMYT 1991 Annual Report (International' Maize and Wheat Improvement Center). Improving the Productivity of Maize and Wheat in Developing Countries. An Assessment of Impact. Mexico, D.F.

24. Commonwealth Mycological Institute (CMI). (1974). Distribution maps, plant disease No. 173, 3rd Edition, Kew, England, Commonwealth Agricultural Bureaux.

25. Crous, P.W., A.B. Van Jaarsveld, L.A. Castlebury, L.M. Carris and Z.B. Pretoriud (2000). Karnal bunt found on wheat in South Africa. http:/ www.sassp.co.2a/x6/newdisease reports/January / feature/Karnal bunt.htm.

26. Dastur, J.F. (1946). Report of the imperial mycologist. Science' Reports of the Agricultural Research Institute, New Delhi, India, 1944-45, pp. 66-72.

27. Datta, R., M.D. Rajebhosale, H.S. Dhaliwal, H. Singh, P.K. Rajnekar and V.S. Gupta (2000). Interspecific genetic variability analysis of Neovossia indica causing Karnal bunt of wheat using repetitive elements. Theor. Appl. Gen. 1 00: 569-575.

28. David, R.G. and J.W. Darrell (1996). Using random amplified polymorphic DNA to analyse the genetic relationship and variability among three species of wheat smut (Tilletia). Bot. Bull. Acad. Sin. 37: 173-180.

29. Delgado, S. (1984). Mexican phytosanitary policy in relation to Karnal bunt. In Karnal bunt disease of wheat- Proceedings of a conference, April 16-18, Cuidad Obregon, Sonora, Mexico, CIMMYT. p. 27.

30. Dhaliwal, H.S. (1989). Multiplication of secondary sporidia of Tilletia indica on soil, wheat leaves and spikes and incidence of Karnal bunt. Canadian J. Bot. 67: 2387-2390.

31. Dhaliwal, H.S. and D.V. Singh (1988). Up-to-date life cycle of Neovossia indica (Mitra) Mundkur. Curr. Sci. 57: 675-677.

32. Dhaliwal, H.S. and D.V. Singh (1989). Production and interrelationship of two types of secondary sporidia of Neovossia indica. Curr. Sci. 58: 614-618.

33. Dhiman, J.S. and P.S. Bedi (1989). Studies on the mode of perpetuation and pathogenic variability in Neovossia indica causing Karnal bunt of wheat. Indian Phytopath. 42: 323.

34. Duran, R. and R. Cromarty (1977). Tilletia indica - A heterothallic wheat bunt fungus with, multiple alleles controlling incompatibility. Phytopathology 67: 812-815.

35. Ferreira, M.A.S.V., Paul W. Tooley, Carlos Casho Hatzilonkas and N.W. Schaad (1996). Isolation of a species specific mitochondrial DNA sequence for identification of Tilletia indica, the Karnal bunt of wheat fungus. Appl. Environ. Microbiol. 61: 8793.

36. Fischer, G.W. (1953). Manual of North American Smut Fungi. Ronald Press Co. New York.

37. Fuentes, S., E. Torres and C. Garcia. (1983). Chemical seed treatment for partial bunt of wheat. Phytopathology 73 : 122 (Abstr.).

38. Fuentes-Davila, G. (1998). Karnal bunt of wheat. In : Bunts and Smuts of Wheat: An International Symposium. pp. 69-81. (Eds., Malik, V.S. and Mathre, D.E.) North American Plant Protection Organization Ottawa, pp. 445.

39. Gartan, S. L., A. K. Basandrai and S.C. Sharma(2004). Identification of multiple resistance sources for rusts, powdery mildew and Karnal bunt in wheat. Crop Improvement. 31: 136-140

40. Gautam, PL, S.K. Malik and D.P. Saini(1977). Note on reaction of promising wheat strains to Karnal bunt. Pantnagar J. Res. 2 : 228-229.

41. Gill, K. S., A.S. Randhawa, S.S. Aujla, H.S. Dhaliwal, A.S. Grewal and I. Sharma. (1981). Breeding wheat varieties resistant to Karnal bunt. Crop Improv. 8 : 73-80.


- 116 -

42. Gill, K. S., I. Sharma and S.S. Aujla (1993). Karnal Bunt and Wheat Production. Punjab Agricultural University, Ludhiana, pp. 153.

43. Hassan, S.F. (1973). Wheat diseases and their relevance to improvement and production in Pakistan, pp. 84-86. Proc. Fourth, FAO/Rockfeller Foundation Wheat Seminar.

44. Hoffmann, J.A 1983. Karnal bunt of wheat. Phytopathology 73 : 782 (Abstr.).

45. Howard, A. and G.L.C. Howard (1909). Wheat in India. I. Production, Varieties and Improvement. Thacker, Spink and Co. Calcutta.

46. Joshi, L.M., B.L Renfro, E.E. Saari, R.D. Wilcoxon and S.P. Raychaudhary (1970). Rust and smut diseases of wheat in India. Plant Dis. Reptr. 54 : 391-j94.

47. Joshi, L.M., D.V. Singh and K.D. Srivastava (1981). Meteorological conditions in relation to incidence of Karnal bunt of wheat in India. Proc. of 3rd Intern. Symp. Plant Pathol., IARI, New Delhi, pp.11.

48. Joshi, L.M., D.V. Singh and K.D. Srivastava (1986). Problems and Progress of Wheat Pathology in South Asia. Malhotra Publishing House, New Delhi, pp. 401.

49. Joshi, L.M., D.V. Singh and K.D. Srivastava. (1980). Present status of karnal bunt in India. Indian Phytopath. 33 : 147-148 (Abstr.).

50. Joshi, L.M., D.V. Singh, K.D. Srivastava and R.D. Wilcoxson (1983). Karnal bunt- A minor disease that is now a new threat to wheat. Bot. Rev. 43: 309-338.

51. Krishna, A. and R.A Singh (1982a). Investigations on the disease cycle of Karnal bunt" of wheat. Indian J. Mycol. & PI. Pathol. 12 : 124.

52. Krishna, A. and R.A Singh. (1982b). Evaluation of fungicides for the control of Karnal bunt of wheat. Pesticides 16: 7

53. Krishna, A. and R.A Singh. (1983). Method of artificial inoculation and reaction of wheat cultivars to Karnal bunt. Indian J. Mycol. & Plant Pathol. 13 : 124-125.

54. Kumar, J. and S. Nagarajan (1998). Role of flag leaf and spike emergence stage of wheat on severity of Karnal bunt. Plant Dis. 82: 1368-1370.

55. Lira, M. (1984). The Karnal bunt situation in north-west Mexico. In Karnal bunt disease of wheat -Proceedings of a conference, April 16-18, 1984, Cuidad Obregon, Sonora, Mexico, CIMMYT, pp. 24-26.

56. Locke, C.M. and AJ. Watson. (1955). Foreign plant diseases intercepted in quarantine inspection. Plant Dis. Reptr. 39 : 518.

57. Mahal, G. S., N. S. Bains, , L. N. Jindla and, A.S. Randhawa(2003). PDW 274: A high yielding durum wheat variety for export. Journal of Research 40: 304

58. Martin, P.M. (1986). Quarantine of Karnal bunt in Canada. p. 29. In Proceedings of the Fifth Biennial Smut Workers Wodcshop. April 2830, 1986. Cuidad Obregon, Sonora, Mexico, CIMMYT.

59. McDoald, F.G., E. Wong and G.P. White (2000). Differentiations of Tilletia species by rep PCR genomic fingerprinting. Plant Dis. 84 : 1121-1125.

60. Medina, C.L. 1985. Effect of different levels of Karnal bunt infection on the quality of wheat and organoleptic characteristics of bread). B.Sc. Thesis. Department of Chemistry and Chemical Engineering. Technical Institute of Sonors, Cuidad Obregon, Sonora, Mexico, pp. 63.

61. Mehdi, V., L.M. Joshi and V.P. Abrol. (1973). Studies on Chapatti quality VI Effect of the wheat grains with bunts on the quality of chapatties. Bull. Grain Technol. 11: 195-197.

62. Mishra, A.K. and K.P. Singh. (1988). Antagonism of Neovossia indica isolates by soil microorganisms. Indian J. Mycol. PI. Pathol. 18 : 79.

63. Mitra, M. (1931). A new bunt of wheat in India. Ann. Biol. 18: 178-179.

64. Mitra, M. (1935). Stinking smut (bunt) of wheat with special reference to Tilletia indica Mitra. Indian J. agric. Sci. 5: 51-74.

65. Mitra, M. (1937). Studies on stinking smut or bunt of wheat in India. Indian J. agri. Sci. 7: 467-478.


- 117 -

66. Mundkur, B.B. (1943a). Karnal bunt, an. air-borne disease. Curr. Sci. 7 : 230-231.

67. Mundkur, B.B. (1943b). Studies in Indian.Cereal smuts.V. Mode of transmission of the Karnal bunt of wheat. Indian J. Agric. Sci. 8 : 54-58.

68. Mundkur, B.B. (1944). A second contribution towards knowledge of Indian ustilaginales. Trans. Brit. Mycol. Soc. 24: 312-334.

69. Munjal, R.L. (1975). Studies on spore germination and control of Neovossia indica,. the causal agent of Karnal bunt of wheat. Indo-USSR Symposium on wheat Diseases, June 5.10, 1975, Krasnodar, USSR

70. Munjal, R.L. (1976). Status of Karnal bunt (N. indica) of wheat in North India during 1968-69 and 1969-70. Indian J. Mycol. &. PI. Pathol,. 5 : 185-187.

71. Nagarajan, S. (1991). Epidemiology of Karnal bunt of wheat incited by Neovossia indica and an attempt to develop a disease prediction system, pp. 1-62, CIMMYT, Technical Report Wheat Programme CIMMYT, Mexico.

72. Nath, R., A.K. Lambat, P.M. Mukewar and I. Rani (1981). Interceptions of pathogenic fungi in imported seed and planting material. Indian Phytopath. 34: 382-386.

73. Rai, R.C. (1983). Studies on loss estimation and chemical and toxicological evaluation of Karnal bunt of wheat. Ph.D. Thesis, G.B. pant University of Agric. & Technology, Pantnagar. pp. 136

74. Rai, R.C. and A. Singh (1978). A note on viability of wheat seed infected with Karnal bunt. Seed Res. 6: 188-190.

75. Rai, R.C. and A. Singh (1979). Effect of chemical seed treatment on seed-borne teliospores of Karnal bunt of wheat. Seed Research 7 : 186-189.

76. Rai, R.C. and A. Singh (1985). A view on seed certification standards for Karnal bunt of wheat. Seed Research13 : 94-98.

77. Rai, R.C. and A. Singh (1985). Estimation of loss in wheat grain weight due to Karnal bunt infection. Indian J. Mycol. PI. Pathol. 15: 125-131.

78. Rai, R.C. and A. Singh (1989). Karnal bunt of wheat. A threat to wheat seed production in eastern Uttarar Pradesh. Narendra Deva J. Agric. Res. 4 : 27-31

79. Rai, R.C., A. Singh and R V. Singh. (1988). Status of Karnal bunt of wheat in eastern Uttar Pradesh. Narendra Deva J. Agric. Res. 3 : 183-185.

80. Rai, R.C., A. Singh and R.B. Rai (1991). Haemotological and biochemical studies on albino rats fed on Karnal bunt infected wheat grains. Narendra Deva J. Agric. Res. 6 : 1-6.

81. Rattan, G.S. and S.S. Aujla (1990). Survival of Karnal bunt (Neovossia indica) teliospores in different types of soil at different depths. Indian J. agric. Sci. 60: 616-618.

82. Royer, M.H. (1988). Comparison of host ranges of Tilletia indica and T. barclayana. Plant Disease 72 : 133-136.

83. Royer, M.H., J.L. Ryner and T.T. Matsumoto. (1986). Host range of Tilletia Indica on several grasses. Phytopathology 76 : 1146 (Abstr.).

84. Sekhon, K.S., A.K. Saxena, S.K. Randhawa and K.S. Gill. (1980). Effect of Karnal bunt disease on quality characteristics of wheat. Bull. Grain Tech. 18 : 208.212.

85. Sekhon, K.S.,S.K. Gupta, A.K. Bakshi and K.S. Gill. (1980). Effect of Karnal bunt on chapati making qualities of wheat grains. Crop Improvement. 7 : 147-149.

86. Sekhon. K.S., S.K. Randhawa, A.K. Sharma and K.S. Gill (1981). Effect of washing/steeping on the acceptability of Karnal bunt infected wheat for bread, cookie and chapatti making. J. Food Sci. Tech. 18: 1-2.

87. Sharma, A. K., D. P. Singh, J. Kumar, Indu-Sharma and B. K. Sharma(2005). Efficacy of some new molecules against Karnal bunt (Tilletia indica) of wheats (Triticum aestivum and T. durum). Indian J. Agril. Sc. 75 : 369-370

88. Sharma, A.K., ,K. S. Babu, R. K. Sharma and Kamlesh Kumar (2007). Effect of tillage practices on Tilletia indica Mitra (Karnal bunt disease of wheat) in a rice-wheat rotation of the indo-gangetic plains. Crop Protection ; 26 : 818-821


- 118 -

89. Sharma, A.K., J. Kumar and S. Nagarajan (1998). Worldwide movement of smuts and bunts. In : Bunts and Smuts of Wheat: An International Symposium. pp.129-136 (Eds. Malik, V.S. and Mathre, DE) North American Plant Protection Organization Ottawa, pp. 445.

90. Sharma, B. K., , A. K. Basandrai and, K.D. Sharma(2004). Variability in Neovossia indica and sources of multiple disease resistance in Triticum spp. and allied genera . 34 : 33-36

91. Sharma, B.K. and A. K. Basandrai(2004). Efficacy of fungicides and plant leaf extracts for the control of Karnal bunt of wheat [Neovossia indica (Mitra) Mundkar].J. Mycol. and Pl. Pathol. 34 : 102-104

92. Sharma, Indu, G.S. Nanda, K. Chand and V.S. Sohu(2001). Status of Karnal bunt (Tilletia indica) resistance in bread wheat (Triticum aestivum).Indian J. of. Agril. Sc. 71: 794-796

93. Sharma, Indu, N. S. Bains, G. S. Nanda and D. R. Satija (2003). Incorporation of Karnal bunt resistance in wheat variety, PBW 343. Crop Improvement 30 : 21-24

94. Sharma, R. C. and Indu Sharma (2004). Comparative efficacy of systemic fungicides against loose smut, Karnal bunt and paddy bunt. Seed-Research 32 : 229-231

95. Shi, Y.L., P. Loomis, D. Christian, L.M. Carries and H. Beung (1996). Analysis of the genetic relationships among the wheat bunt fungi using RAPD and ribosomal DNA markers. Phytopathology 86: 311-318.

96. Siddhartha, V.S. (1992). Epidemiological Studies on Karnal Bunt of Wheat, Ph.D. Thesis, Division of Plant Pathology, IARI, New Delhi, pp. 105.

97. Siddhartha, V.S., D.V. Singh,K.D. Srivastava, and R. Aggarwal (1995). Some epidemiological aspects of Karnal bunt of wheat. Indian Phytopath. 48: 419-426.

98. Singh, A. (1994). Epidemiology and Management of Karnal bunt Disease of Wheat, Research Bulletin No. 127., G.B. Pant Univ. of Agril. & Technology, Pantnagar, India. pp. 167.

99. Singh, A. and R. Prasad (1978). Date of sowing and meteorological factors in relation to occurance of Karnal bunt of wheat in U.P. Tarai. Indian. J. Mycol. & PI. Pathol. 8 : 2 (Abstr.).

100. Singh, A., A.N. Tewari and R.C. Rai. (1981). Control of Karnal bunt of wheat by a spray of fungicides. Indian Phytopath. 38 : 104-108.

101. Singh, A., K.P. Singh and A.N. Tewari (1988a). Salient findings of Karnal bunt research at Pantnagar. Department of Plant Pathology, G.B. Pant University of Agric. & Technology, Pantnagar pp. 18.

102. Singh, A., K.P. Singh and A.N. Tewari (1988b). Chemical control of Karnal bunt of wheat. Indian J. Mycol. PI. Pathol. 18 : 88-89 (Abstr.).

103. Singh, B. and S.C. Mathur (1953). Bunts of wheat. Agric. & Animal Husb. India 3 : 10-12.

104. Singh, D. (1986). Bunts of wheat in India. In Problems and Progress of Wheat Pathology in South Asia. Malhotra Publishing House, New Delhi, pp. 124-161

105. Singh, D. V. (2005). Karnal bunt of wheat: a global perspective . Indian-Phytopath. 58 : 1-9

106. Singh, D.(1980). A note on the effect of Karnal bunt infection on vigour of wheat seed. Seed Research 8: 81-82

107. Singh, D.P., V. C. Sinha, L.B. Goel, Indu sharma, ,S.S. Aujla, ,S.S. Karwasra, M.S. Beniwal, Amerika Singh, K.P. Singh, A.N. Tewari, ,P.S. Bagga, B.K. Sharma, D.V. Singh, K.D. Srivastav, Rashmi Aggrawal and B.R. Verma ( 2003) Confirmed sources of resistance to Karnal bunt in wheat in India Plant-Disease-Research 18: 37-38

108. Singh, D.V. and K.D. Srivastava (1997). Influence of Cropping System on Recurrence of Karnal bunt (Neovossia indica) of Wheat. Final Report, ICARCess Fund Project, Division of Plant Pathology, IARI, New Delhi, India, pp. 29.

109. Singh, D.V. and K.D. Srivastava (2001). Implications of Karnal bunt on grain trade. In : Role of Resistance in Intensive Agriculture. pp 78-85 (Eds., Nagarajan, S. and Singh, D.P.) Kalyani Publishers, New Delhi, pp. 259.

110. Singh, D.V., K.D. Srivastava and L.M. Joshi. (1985) Present status of Karnal bunt of wheat in relation to its distribution and varietal susceptibility. Indian Phytopath. 38 : :507-505


- 119 -

111. Singh, D.V., K.D. Srivastava and R. Aggarwal (1998). Karnal Bunt; constraints to wheat production and management. In : Bunts and Smuts of Wheat: An International Symposium pp. 201-222. (Eds., Malik, V.S. and Mathure, D.E.) North American Plant Protection Organization, Ottawa, pp. 445.

112. Singh, D.V., K.D. Srivastava, L.B. Goel, L.M. Joshi and R.S. Gupta (1977). Incidence of Karnal bunt in North-western India during 1974-75. Indian Phytopath. 30: 431-432.

113. Singh, D.V., L.M. Joshi and K.D. Srivastava (1983). Karnal bunt, new threats to wheat in India. In : Recent Advances in Plant Pathology. Prof. HK Saksena Festschrift. pp. i21-135 (Eds. Hussain, A., Kishan Singh, Singh, B.P. and Agnihotri, V.P.) Print House (India) Lucknow.

114. Singh, R.A. and A. Krishna (1982). Susceptible stage for inoculation and effect of Karnal bunt on viability of wheat seed. Indian Phytopath. 35: 54-56

115. Singh, Rajender; M. S Beniwal and S.S. Karwasra (2002). Evaluation of fungicides as seed dressings against Karnal bunt (Neovossia indica) of wheat.Tests of Agrochemicals and Cultivars. 2002; (23): 6-7

116. Smith, O.P., G.L. Peterson, R.J. Beck, N.W. Schaad and M.R. Bonde (1996). Development of a PCRbased method for identification of Tilletia indica, causal agent of Karnal bunt of wheat. Phytopathology 86: 115-122.

117. Torabi, M. and N. Jalalian (1996). First report on the occurrence of partial bunt on wheat in the southern parts of Iran. Seed and Plant J. Agric. Res. pp. 8. Seed and Plant Improvement Institute (Iran Islamic Republic).

118. Tunwar, N.S. and S.V. Singh. (1988). Indian minimum seed certification standards. The Central Seed Certification Board, Department of Agriculture and Cooperation, Ministry of Agriculture, Government of India, New Delhi, 388 pp.

119. Warham, E.J. and D. Flores (1988). Farmer surveys on the relationship of agronomic practices to Karnal bunt disease of wheat in the Yaqui Valley, Mexico. Tropical Pest Management 34: 373-381.

120. Warham, E.J. and J.M. Prescott. (1984). Effect of chemicals on teliospore germination of Karnal bunt (Neovossia indica). Phytopathology 74 : 885 (Abstr.).

121. Warham, E.J., A. Mujeeb-Kazi and V. Rosas. (1986).Karnal bunt (Tilletia indica) resistance screening of Aegilops speices ,and their practical utilization for Triticum aestivum improvement. Can. J. Plant Pathol. 8 : 65-70.

122. Warharm, E.J. (1986). Karnal bunt disease of wheat: a literature review. Tropical Pest Management 32 : 229-242.

123. Warharm, E.J. (1990). Effect of Tilletia indica infection on viability, germination and vigour of wheat seed. Plant Disease 74: 130-132.

124. Warharm, E.l (1984). A comparison of inoculation methods for Karnal bunt (N. indica). Phytopathology 74; 856-857(Abstr.)

125. Ykema, R.E., J.P. Floyd, M.E. Palm and G.L. Peterson (1996). First report of Karnal bunt in the United States. Plant Dis. 80: 1207.

126. Zadoks, J.C., T.T. Chang and C.F. Konzak (1974). A decimal code for the growth stage of cereals. Eucarpia Bulletin 7: 1-10.


- 120 -

Entomopathogenic Nematodes and their Role in Biological Control of Insect Pests

A.U. Siddiqui

Department of Nematology, Maharana Pratap University of Agriculture & Technology, Udaipur-313 001

Insect pests dominate our world. They constitute the largest class not only of Animal

kingdom but also of whole living world. The number of known species of insects is estimated to

vary from 7, 00,000 - 15, 00,000 which constitute 70-90 % of the known species of the Animal

kingdom (Pradhan, 1964, 83). The annual yield losses due to insect pests on all important

agricultural crops, estimated to about Rs. 29240 cores based upon 1994-95 minimum support

prices fixed by the ministry of Agriculture, Govt. of India (Dhaliwal and Arora, 1996). Considering

insects on one of the most important constraints in agricultural production in India, biological

control of crop pests have been considered by many to be the most viable alternative, is

economical has long term control, without risk to human beings, cattle and other non-target

organisms, this is evident from the fact that annual growth increase in insecticides is 1-2 % and

that of microbial insecticides 10-25 % (Ahmed and Leather, 1994).

Nematodes are simple, roundworms, colourless, unsegmented and lacking appendages,

may be free living predaceous or parasitic. Many of the parasitic species cause important diseases

of plant, animals and humans. Other species are beneficial in attacking insect pests, mostly

sterilizing or otherwise debilitating their host. A very few case insect death but these species tend

to be difficult (Tetradomatids) or expensive (Mermithids) to mass produce, have narrow host

specificity against pests of minor economic importance, posses modest virulence (Sphaeruliids) or

otherwise poorly suited to exploit for pest control purposes. The only insect parasitic nematodes

possessing an optimal balance of biological control attributes are entomopathogenic or insecticidal

nematodes in the genera Steinernema and Heterorhabditis. These multicellular metazoans occupy

a biocontrol middle ground between microbial pathogens and predators / parasitoids, and are

invariably lumped with pathogens presumably because of their symbiotic relationship with bacteria.

Generally several nematodes infect a single insect host, penetrating the insect’s body

cavity, usually through natural body openings including the mouth, anus, or breathing pores

(spiracles). Heterorhabditids can break the outer cuticle of the insect using a dorsal tooth or hook.

Once inside the body cavity of the host,the infective juveniles release bacteria that live

symbiotically within the nematode’s gut. The nematode bacterium relationship is highly specific

only Xenorhabdus spp. Bacteria co-exists with steinernematids, and only Photorhabdus bacteria

cvo-exist with heterorhabditids. Once released into the host, the bacteria multiply quickly and

under optimal conditions cause the host to die within 24 to 48 hours.

Steinernema and Heterorhabditis sp. (order Rhabditida) are nematodes parasitic on

insects. They transmit bacteria which are lethal to their host, a characteristic which makes them

more suitable for biological control of insects than any other nematode group. Over the last two


- 121 -

decades Steinernematids and Heterorhabditids have become increasingly popular in insect

control. Among their useful attributes are:

i) A wide host range

ii) The infective juveniles can be readily and cheaply cultured, either on host or on

artificial media

iii) Cultures can be stored for extended periods

iv) They can be easily applied

v) The nematode species are resistant to a variety of environmental conditions, can

actively find and penetrate susceptible hosts, and cause up to 100% mortality within

a few days.

vi) They are harmless to higher organisms and plants

Mass Production of Entomopathogenic Nematodes

Steinernematid and Heterorhabditid nematode products are available worldwide for control

of insect pests largely due to the progress made in mass production formulation and field efficacy.

The exemption of the nematodes from registration, their ability to infect and reproduce on a broad

spectrum of insects and safety to non-target organisms have made them an attractive proposition

commercially. Axenic culture process for Steinernema carpocapsae was first developed by Glaser

et al. (1940). Production on a commercial scale had been accomplished by using inexpensive

protein and sterol sources. In the past EPN have been cultured on a variety of substances like

potato mash, ground veal pulp, peptone-glucose agar and pork kidney, homogrized animal tissue,

dog food and chicken offal homogenate. The cost of mass production using these methods should

not be a major constraint for commercialization.

Utilization of any biological agent is dependent upon its availability in sufficient quantity at

acceptable costs. Steinernematids and Heterorhabditids can produced by both in vivo and in vitro

methods.

Yield of Steinernema spp. from the larvae of greater wax moth (G. mellonella)

S. No. Size of larva Mean weight (mg) of larva

Nematode IJs Harvested/larva

Nematode IJs/mg

1. Small (10-12 mm) 89 58340 655.50

2. Medium (14-16 mm) 147 62500 425.17

3. Large (20-22 mm) 223 90945 407.82

Yield of Heterorhabditis spp. from the larvae of greater wax moth (G. mellonella)

S. No. Size of larva Mean weight (mg) of larva

Nematode IJs Harvested/larva

Nematode IJs/mg

1. Small (12-14 mm) 92 106000 1152.17

2. Medium (17-19 mm) 151 142666 944.80

3. Large (23-25 mm) 257 201520 887.75


- 122 -

In vivo mass production

Karunakar et al. (1992) studied the production of Steinernema glaseri and Heterorhabditis

indicus on sugarcane internode borer, Chilo sacchariphagus indicus (Kapur). They recorded on an

average 37,335.8 IJs/larva in S. glaseri and 2,10,283.3 IJs/larva in H. indicus when both were

inoculated @ 25 IJs/larva. Further, they concluded that the multiplication of IJs/unit body weight of

host was higher in H. indicus than S. glaseri.

Hussaini et al. (1998) reported the nutritional requirements of infective juveniles of native

entomopathogenic nematode Steinernema sp. from insect hosts Galleria mellonella (L.), Agrotis

ipsilon (H.), Spodoptera litura (F.), Helicoverpa armigera (H.) and Corcyra cephalonica (Stainton).

G. mellonella was found to be the most suitable host for in vivo production with yields of

5,14,383/g larva followed by C. cephalonica, H. armigera, A. ipsilon and S. litura with 20, 89, 90

and 93 per cent less production, respectively, in comparison to G. mellonella.

Prabhuraj et al. (2000) tested a modified trapping technique for the entomophilic

nematodes for its efficacy in recovery of naturally occurring insect parasitic nematodes, optimum

time of removal of baited traps from the soil and at the same time prevention of attack by predatory

ant, Solenopsis geminata. The highest nematode recovery (13.5 %) and the least ant attack were

achieved on fourth day of trapping. Modified trapping technique was found effective in the

prevention of predatory ant attack which subsequently increased the efficacy of nematode

recovery.

Sturhan and Mracek (2000) collected forty soil samples from forests and other biotypes in

Germany and the Czech Republic for the presence of entomopathogenic nematodes using the

Galleria bait method at the same time as a sieving-decanting method for direct extraction of

infective stage juveniles. Five Steinernema species were recovered from the samples from

Germany and four species from the samples from Czechia. All five species were recovered by

both methods, but the baiting technique was generally less effective and mixtures of species were

frequently undetected. The direct extraction method provided quantitative estimation of infective

stage juveniles density but no information on their infectivity or on morphological characters of

adults, and nematode cultures could not be established.

Zaki et al. (2000) studied or in vivo culturing of entomopathogenic nematodes,

Heterorhabditis bacteriophora (Poinar) and Steinernema carpocapsae on silk worm Bombyx mori

(L.). Both H. bacteriophora and S. carpocapsae (500 nematodes/larva) caused 100 per cent

mortality of 5th instar larvae of B. mori after 24 and 48 hrs. of application in case of injection and

topical methods, respectively. The average number of nematodes that emerged out from the 3rd

instar larva of silkworm was 2750.

Elawad et al. (2001) reported that progeny production of a new entomopathogenic

nematode Steinernema abbasi in various lepidopterous prepupae was investigated most dauer

juveniles (DJs) developed in the greater wax moth, Galleria mellonella L. (2,34,000), but the boll

worms Helicoverpa virescens (2,20,000) and Spodoptera exigua (1,66,000) were also good host. \


- 123 -

Prabhuraj et al. (2001) tested the suitability of mulberry silk worm, Bombyx mori and root

grub, Holotrichia serrata, for in vivo mass production of Steinernema glaseri and an unidentified

species of Heterorhabditis, along with the standard host, Galleria mellonella. Fifty last instar larvae

of G. mellonella, B. mori and Holotrichia serrata were exposed to S. glaseri at 13270 and 3250

infective juveniles (IJs)/larva and Heterorhabditis sp. at 35414 and 275107 IJs/larva. B. mori was

the most suitable host for the production of S. glaseri and Heterorhabditis sp. recording 1191032.6

and 8807110.9 IJs/rupee, respectively. G. mellonella was the next best alternative, which

produced 983611.5 and 5080930.8 IJs/rupee of S. glaseri and Heterorhabditis sp., respectively.

Holotrichia serrata was the least suitable host, which yielded 896038.7 and 128399.8 IJs/rupee of

Heterorhabditis sp. and S. glaseri, respectively.

Gaugler et al. (2002) reported one component of nematode production in the USA in a

cottage industry of low volume producers using in vivo technology, based on a method devised in

1927: the white trap. They reported the first scalable system for in vivo nematode mass

production. Unlike the white trap, there is no requirement for nematode migration to a water

reservoir. The LOTEK system of tools and procedures provides process technology for low cost,

high efficiency mass production. The harvester collects 97% of Heterorhabditis bacteriophora

(Poinar) that emerged from Galleria mellonella (L.) cadavers in 48 hrs. The separator removes

97.5 % of the wastewater in three passes, while nematode concentration increased 81-fold.

Rajkumar et al. (2002) studied the mass multiplication of Steinernema sp. and

Heterorhabditis sp. on greater wax moth, Galleria mellonella. The infective juveniles of

Steinernema sp. and Heterorhabditis sp. were inoculated on three categories of Galleria mellonella

based on the larval size and body weight. The difference recorded in both species with regard to

the yield of nematode varied due to the size and body weight of the Galleria mellonella larvae.

Singh and Yadava (2002) reported that the nematode, Heterorhabditis bacteriophora was

found capable to multiply on the larvae of greater wax moth Galleria mellonella with its associated

bacterium Xanorhabditis luminercens by attacking and killing the larvae within 48 hrs. The

maximum yield of nematode (203320 IJs/larva) were harvested from the large size (24-26 mm)

larvae having 230 mg body weight whereas, minimum (106400 IJs/larva) were harvested from the

small size (13-15 mm) of larva having 95 mg body weight and it was observed that number of

nematode IJs/larva increased with the increase in larval size as well as body weight.

In vitro mass production

Hussaini et al. (2000) carried out mass multiplication of Steinernema sp. (SSL2) PDBC EN

13.21 in four combinations of dog biscuit media in comparison with Wouts medium. The cost of

production was also evaluated. After a culture time of thirty days and an initial inoculum of 500 IJs

per 250 ml, a maximum yield of 30.58 x 105 IJs was recorded from Wouts medium followed by dog

biscuit + peptone + beef extract (24.5 x 105), dog biscuit + beef extract (18.40 x 105), dog biscuit +

peptone (12.20 x 105) and dog biscuit + bacterial culture (10.14 x 105). The cost of production for

10 lakh IJs was highest for the dog biscuit + bacterial culture followed by dog biscuit + peptone +


- 124 -

beef extract, dog biscuit + peptone, dog biscuit + beef extract and Wouts medium. Wouts medium

was found to be the best both in terms of yield/gram of medium and cost of production per ten lakh

IJs.

Gulsar Banu and Rajendran (2001) reported that different media viz. Wouts medium,

Wouts medium supplemented with bengalgram flour or green gram flour instead of soyflour and

coconut oil or groundnut oil instead of corn oil have been tried under laboratory condition at 25 oC.

Medium was coated on 1 cm3 polyurethene foam and Steinernema sp. isolated from Kerala was

inoculated @ 400 IJs/flask. Maximum multiplication was recorded in Wouts media supplemented

with bengalgram flour and coconut oil. Morphometrics of infective juveniles cultured in vitro is

compared with in vivo cultures on Galleria mellonella. Virulence of in vitro cultures were also

studied against Helicoverpa armigera.

Narkhedkar et al. (2001) studied on natural occurrence of EPN in cotton growing

ecosystems using Corcyra cephalonica and Galleria mellonella as bait. Heterorhabditids were

prominent in samples from south and central zones. Sixteen EPN isolates were isolated from

cotton growing zones of southern central and northern India. Three mass production protocols viz.

dog food medium, peptone- kidney medium and Wouts medium were found to be favourable for

nematode mass culturing.

Vyas et al. (2001) attempted in vitro mass production of native Steinernema sp. using 21 animal

and plant protein based media. Maximum production of nematodes was recorded in hen-egg yolk

medium which was economically better than universally used dog food biscuit agar. Production of

the entomopathogenic nematode was poor in plant protein compared to animal protein based

media.

For a biocontrol agent to be successful it should be amenable for mass production on large

scale the ready availability of the organism in required quantity and at competitive cost makes

them acceptable among entrepreneurs and farmers. Nematodes of both the genera can be mass

produced in both solid and liquid cultures. Recently, commercial nematodes are produced by solid

media process or the liquid fermentation method. Large scale commercial yields of EPN require

economies of scale (Kaya and Gaugler, 1993) (decrease costs in yield with an increase scale of

operation) otherwise the production will be confined to cottage industries. In India where labour

costs are minimum the solid media technology is adaptable and can be developed into a cottage

industry utilizing locally available population and materials. Liquid fermentation process is highly

efficient, economical and suitable for industrialized countries.

The nematode based pesticide must be able to complete in relative terms with chemical

pesticide in field efficacy is an important and can affect handling, application, persistence and

stability in storage. Timing soil applications of nematode with the life cycle of target insect is a key

factor. During the past few years, a distinct cottage industry has emerged that utilizes the in vivo

process for nematode mass production for sale, specially in the home lawn and garden markets in

the west.


- 125 -

In vivo: Progeny production of different Steinernema spp. and Heterorhabditis spp. were

evaluated in different lepidopteran insects pests. Maximum yield of all the isolates was observed in

final instar larvae of Gallaria mellonella.

Table 1. Mass production (in vivo) of EPNs from different hosts S. No. Insect host Nematode Production

(IJs/larvae) References

1. Galleria mellonella Steinernema feltiae Heterorhabditis bacteriphera Steinernema sp. Heterorhabditis sp. Steinernema sp. STUDP strain Heterorhabditis sp. HODP strain

2,00,000 3,50,000

79145 1,34,300

Dutky et al. 1964 Milstead and Poinar 1978 Rajkumar et al. 2001 Sharma et al. 2003

2. Chilo sacchariphagus indicus

S. feltiae S. glaseri H. indicus

1,27,000 3,70,000 2,10,000

Karunakar et al. 1992

3. Spadoptera exiguina

S. abbassi 1,66,000 Elawad et al. 2001

4. Helicoverpa armigera

S. abbassi 2,20,000 Elawad et al. 2001

At present S. carpocapsae, S. feltiae, S. glaseri and S. riobrave can be consistently and

efficiently produced in 7500-80000 litre fermenters with a yield capacity as high as 150000

infective juveniles/ml. (Georgis and Manweiler, 1994). The in-vivo culture method using V. blender

reduces the need for fermenter thus reducing the cost of mass production.

Formulations

Commercial formulations are developed to maintain product stability during storage and

transportation. The successful market acceptance of nematode based products depends heavily

on their stability during shipping and storage as well as their ease of use and consistent

performance under field conditions. Significant progress has been made in the nematode

formulation technique.

The first attempts at formulation of EPN were initiated in 1979, but at best, shelf-life was

about one month. Presently shelf-life of Steinernema carpocapsae in water dispersible granules is

4-5 at room temperature and 9-12 months under refrigeration respectively. All commercial

formulations are developed to maintain product stability during storage and transportation, current

formulations being mixed with water and sprayed against the target pest.

Minimum mass-rearing and formulation costs are required before nematode-based

products can become competitive chemical insecticides. The successful market acceptance of

nematode based products depends heavily on their stability during shipping and storage, as well

as their ease of use and consistent performance under field conditions. Stability refers to

maintenance of nematode quality through out all stages of the production process.


- 126 -

Formulations of nematodes is important and can affect handling application persistence

and stability in storage. Formulation of stability is also achieved by partially desiccating and

immobilising in specific carriers, compared to many biocontrol agents nematodes as biopesticides

have a good self life and significant progress has been made in the nematode formulation

technique. Most can be stores under refrigeration in aqueous suspension under adequate supply

of oxygen. Temperature requirements depends upon species. General range for steinernematids

is 5-10 oC and 10-15 oC for heterorhabditeds (Georgis, 1990b). Spray application using a

nematode suspension in water is straight forward, inexpensive and often effective.

Kaya and Nelson (1985) suggested that encapsulation of entomogenous nematodes with

seed has potential to protect roots from insect attack. Nematode escaped from the capsule within

7 days, as the seed germinated it has an opening for the nematode to escape.

Table 3. Different formulations of nematodes

S. No. Formulations References

1. Novel alginate capsules containg nematode

Kaya and Nelson, 1985 Poinar et al., 1985 Kaya et al., 1987

2. Wheat bran bait pellets Capinera et al., 1988

3. Alfa alfa-wheat bait pellets Capinera and Hibbard, 1987

Table 4. Commercial products available in international market

Nematode species Product formulation Country

Steinernema carpocapsae ORTHO Biosafe USA

Bio Vector USA

Exhibit USA

Sanoplant Switzerland

Boden Nutzlinge Germany

Helix Canada

X-GNAT USA

Vector TL USA

S. feltiae Magent USA

Nemasys UK

Stealth UK

Entonem USA

S. riobrave Vector MG USA

Bio Vector USA

S. scapterisci USA

Heterorhabditis bacteriophora Otinem USA

H. megidis Nemasys UK

S. carpocapsae Green commandos, Soil commandos

India

In vitro production

(a) In vitro production of EPN in different artificial media :

Plant and animal protein media were evaluated for in vitro production of indigenous isolates

of S. carpocapsae, S. bicornutum and S. tami and one of H. indica. The flasks with foam chips


- 127 -

were inoculated with different isolates of Steinernema spp. and incubated at 24 ± oC for 25 days

was done by Hussaini et al. (2002). Of the eight artificial media evaluated for Steinernema spp.,

four media viz., wout’s medium, modified egg yolk, soyflour + cholesterol an modified dog biscuit

media yielded highest number of IJs of S. carprcapsae, S. tami, and H. indica PDBCEN. Maximum

number of co S. carprcapsae was observed on modified dog biscuit, while S. tami gave maximum

yield of IJs on modified egg yolk medium. H. indica gave maximum yield of IJs on wout’s medium

S. bicornutum and S. abbasi did not multiply on any of the 8 media tried.

Table 5. Yield of IJs in artificial media

Isolate Medium Yield (lakhs/250 ml flask)

S. abbasi Chicken offal 78.75

S. tami Egg yolk 69.80

S. carpocapsae Chicken offal 98.60

Steinernema sp. SSL2 Egg yolk 54.38

H. indica 13.3 Soyflour + cholesterol 44.95

H. indica 6.71 Soyflour + cholesterol 45.65

Table 6. Synthetic media for mass rearing of Entomophilic nematodes

Synthetic medium

Nematode species

Incubation period

Temperature Nematodes harvested

Reference

Wheat bran S. feltiae 3 weeks 25 oC 104 Abe (1987)

Wheat bran + salad oil

S. feltiae 3 weeks 25 oC 107 Abe (1987)

Dog food agar medium

S. feltiae - - 105/g of medium

Hara et al. (1981)

Beef extract, peptone, corn meal, water on sponge

S. feltiae - - - Li (1984)

Nutrient broth, yeast extract, veg. oil flour coated on sponge

H. heliothidis 4 weeks 25 oC 10 x 106/250 ml flask

Wouts (1981)

Soyapeptone 3% + yeast extract 3% + chick embryo extract 10% medium

S. glaseri - - 10.051/week for 93 day

Tarakanov (1980)

Kidney/fat homogenate

S. feltiae S. bibionis S. glaseri H. bacteriophora H. heliothidis (NZ)

2-3 weeks 20-30 oC 38 x 106/30 flask 29 x 106/73 flask 8 x 106/11 flask 36 x 106/10 flask 32 x 106/15 flask

Bedding (1981)

Yeast extract, soyflour, egg and lard

S. carpocapsae

20 days 19 oC 38 x 106/flask

Han et al. (1993)


- 128 -

Field control of target pests with EPN

Crop Pest EPN species Reference

Mushroom Lycoriella auripila L. mali L. solani Megaselia halterata

S. feltiae Grewal et al. (1993)

Bradysia spp. S. feltiae Gouge and Hague (1995)

Cabbage Delia radicum D. floralis

S. feltiae H. bacteriophora

Bracken (1990)

Cabbage Plutella xylostella S. carpocapsae H. bacteriophora

Yang et al. (1999)

Grass Popillia japonica H. bacteriophora Downing (1994)

Turf P. japonica Yeh and Alm (1995)

Sweet Potato Cylas formicarius S. carpocapsae Jannsen et al. (1990)

Apple Cydia pomonella S. carpocapsae Lacey and Unruh (1998)

Citrus Phyllocnistis citrella S. carpocapsae Beatie et al. (1995)

Carrot Listronotus oregonensis S. carpocapsae Belair and Boivin (1995)

Ornamental Otiorhynchus sulcatus S. carpocapsae Mracek et al. (1993)

Citrus Diaprepes abbreviatus S. carpocapsae Shapiro and Mc Coy (2000)

Maize Helicoverpa armigera S. riobave Cabanillas and Raulston (1996)

Spruce Cephalcia abietis S. kraussei Mracek and David (1986)

Maize Diabrotica barberi S. feltiae Thurston and Yale (1990)

Cotton Spodoptera littoralis Earias insulana

S. carpocapsae Glazer et al. (1992)

Current use of Steinernema and Heterorhabditis nematodes as biological control organisms

Crop Insect Pest Nematode Species

Artichokes Artichoke plume moth S. carpocapsae

Berries Root weevils H. bacteriophora, S. glaseri, H. marelatus

Cranberries Root weevils H. bacteriophora S. carpocapsae

Cranberry girdler S. carpocapsae H. bacteriophora H. marelatus

Hoplia grub H. bacteriophora

Cranberry root worm H. bacteriophora

Mint Mint root borer, root Weevils, mint flea beetles

S. carpocapsae

Landscape, ornamental trees and shrubs

Borers S. carpocapsae

Mushrooms Sciarid flies S. feltiae

Ornamentals Root weevils H. bacteriophora H. megidis, H. marelatus

Wood borers S. carpocapsae H. bacteriophora

Fungus gnats S. feltiae

Fungus gnats S. feltiae

Scarabs H. bacteriophora

Billbugs H. bacteriophora

Armyworm, cutworm, webworm S. carpocapsae

Cranefly S. carpocapsae

Vegetables root and cole Root maggots, cutworms, armyworms

S. carpocapsae


- 129 -

Lab and filed tests using Steinernematids and Heterorhabditids against various insect pests in India

Entomopathogenic nematodes Insect pest species References

S. glaseri (NC 34), S. carpocapsae (DD 136)

Holotrichia consanguinea Shanthi and Sivakumar (1991)

S. carpocapsae Cnaphalocrocis medinalis Srinivas and Prasad (1991)

S. feltiae S. litura Singh et al. (1992)

Steinernema sp. Papilio sp. Singh (1993a)

S. carpocapsae, H. bacteriphora Heterorhabditis sp.

Amsacta albistriga Bhaskaran et al. (1994)

S. carpocapsae (DD 136) S. litura Sezhian et al. (1996)

Steinernema (7 isolates) Heterorhabditis (4 isolates)

H. armigera Vyas et al. (1998)

S. carpocapsae, S. bicornutum Heterorhabditis indica

A. ipsilon A. segetum

Hussaini et al. (2000)

S. glaseri, H. indica Holotrichia serrata Leucopholis lepidophora

Karunakar et al. (2000)

S. glaseri, S. carpocapsae, S. feltiae, Steinernema (Ecomax strain), S. bicornutum, Heterorhabditis, (Ecomax strain)

Plutella xylostella Shinde et al. (2000)

S. carpocapsae, S. bicornutum, Heterorhabditis indica

Leucinodes orbonalis Hussaini et al. (2002)

Heterorhabditis sp. S. litura Rajkumar et al. (2002)

Use of EPN against insect pests in India

Pest/disease Crop Bioagent/Formulation Reference

Tryporyza incertulus Rice, Sugarcane

S. carpocapsae Rao and Manjunath (1996)

Chilo partellus Maize Steinernema sp. Mathur et al. (1966)

Tryporyza incertulus C. suppressalis Pseudaletia separata

Paddy S. carpocapsae Israel et al. (1969a)

Rice pests Paddy S. carpocapsae Yadava and Rao (1970)

Arctidae, Lymantridae, Noctuidae, Pyralidae

S. carpocapsae Mathur et al. (1971)

T. incertulus Rice S. carpocapsae Rao et al. (1971)

Athalia proxima, Aulacophora foveicollis, Diacrisia obliqua, Dysdercus cingulatus, Heliothis armigera, Leucinodes orbonalis, S. litura

S. carpocapsae Singh and Bardhan (1974)

A. ipsilon, A. segetum, Amathes c-nigrum, and white grubs

Steinernema sp. Singh (1977)

Papilio demoleus S. carpocapsae Srivastava (1978)


- 130 -

Anomala sp. S. litura

Potato S. carpocapsae Rajeswari Sundarababu et al. (1984)

H. armigera, C. partellus

S. carpocapsae Gupta et al. (1987)

S. litura Bioefficiency test

S. carpocapsae S. feltiae

Narayanan and Gopalakrishnan (1987)

H. armigera Mortality tests S. carpocapsae S. feltiae

Ghode et al. (1988)

Orthacris simulans, Drasterius sp. Papilio aristolochiae and Ergolis merione C. cephalonica

Susceptibility tests

H. bacteriophora Sivakumar et al. (1989)

Cnaphalocrosis medinalis S. litura

Rice S. carpocapsae S. carpocapsae, S. feltiae

Srinivas and Prasad (1991) Singh et al. (1992)

Papilio sp. Citrus Steinernema sp. Singh (1993)

Amsacta albistriga S. carpocapsae H. indica, H. bacteriophora

Bhaskaran et al. (1994)

Pieris brassicae, Alphitobius diaperinus, Oryzaephilus mercator

S. feltiae, S. carpocapsae

Mathur et al. (1994)

Basilepta fulvicorne Conogethes punctiferalis

S. feltiae H. glaseri

Balu and Varatharasan (1991)

Odoiporus longicollis H. indica Padmanabhan et al. (2002)

Leucinodes orbonalis Brinjal Steinernema carpocapsae Heterorhabditis indical spray formulation

Hussaini et al. (2002a)

A. ipsilon Tomato S. bicornutum/bait & alginate capsule

Hussaini et al. (2001i)

A. ipsilon S. carpocapsae S. abbasi and H. indica/talc based

Hussaini et al. (2003)

H. armigera Pigeon pea H. indica PDBC (2001)

H. armigera Cotton H. indica PDBC (2001)

S. litura Tobacco nurseries

S. carpocapsae

Sitaramaiah et al. (2003)

REFERENCES

1. Capinera, J.L. and Hibberd, B.E. 1987. Bait formulations of chemical and microfial insecticides for suppression of crop feeding grasshoppers. Journal of Agricultural Entomology 4 : 337-344.

2. Copinera, J.L., Pelissier, D., Menout, G.S. and Epsky, N.D. 1988. Control of block cut worm, Agrotis ipsilon with entomogenous nematodes. Journal of Imertebrate Pathology 52 : 423-435.

3. Dutky, S.R., Thompson, J.V. and Cantwell, G.E. 1964. A technique for mass propagation of the DD-136 nematode. Journal of Insect Pathology 6 : 417.


- 131 -

4. Elawad, S.A.; Gowen, S.R. and Hague, N.G.M., 2001. Progeny production of Steinernema abbasi in lepidopterous larvae. International Journal of Pest Management. 47 (1) : 17-21.

5. Georgis, R. 1990b. Formulation and application Technology. In : Entomopathogenic nematodes in Biological Control. Gauglar R. and Kaya H.K. (eds.), CRC press, Boca Raton, FI.

6. Karunakar, G., David, H. and Easwaramoorthy, S. 1992. Influence of dosage of Steinernema corporapsae, S. glaseri and Heterorhabditis indica on mortality of the host and multiplication of infective juveniles in sugarcane internode borer, Chilo sacchariphagus indicus. Journal of Biological Control 6 : 26-28.

7. Kaya, H.K. and Nelson, C.E. 1985. Encapsulation of steinernematid and heterorhabditid nematodes with calcium alginate. A new approach for insect control and other applications. Environmental Entomology 14 : 572-574.

8. Kaya, H.K., Mannion, C.M., Burlando, T.M. and Nelson, C.E. 1987. Escape of Steinernema feltiae from alginate capsule containing tomato seeds. Journal of Nematology 19 : 287-291.

9. Milstead, J.E. and Poinar, G.O. Jr. 1978. A new entomogenous nematode for pest management systems. California Agriculturist 32 : 12.

10. Poinar, G.O. Jr., Thomas, G.M., Lin, K.C. and Mookerjee, P. 1995. Feasibility of enfedding parasitic nematodes in hydrogels for insect control. IRCS Medical Science 13 : 754-755.

11. Rajkumar M., Parihar, A. and Siddiqui, A.U., 2002. Effect of entomopathogenic nematode Heterorhabditis sp. against Tobacco caterpillar, Spodoptera litura (F.) (Abst.). National Symposium Biodiversity and Management of Nematodes in Cropping Systems for Sustainable Agriculture. A.R.S. Durgapura (Jaipur), 11-13

th Nov, 2002 :

75 pp.

12. Rajkumar M.; Parihar, A. and Siddiqui, A.U., 2002. Mass multiplication of indigenous entomopathogenic nematodes from Udaipur (Abst.). National Symposium Biodiversity and Management of Nematodes in Cropping System for Sustainable Agriculture. A.R.S. Durgapura 11-13

th Nov. 2002 : 77 pp.

13. Sharma, R., Parihar, A. and Siddiqui, A.U. 2003. Investigations on host range and mass multiplication of entomopathogenic nematodes Steinernema sp. and Heterorhabditis sp. M.Sc. thesis, MPUAT, Udaipur, pp.


- 132 -

Recent Advances in the Management of Maize Diseases

S.C. Saxena Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Maize (Zea maysL.) is one of the important cereal crop of the country grown over 7.47 m

ha with a production of 14.72 m tones and 1.98 ton productivity. It is attacked by over 65 diseases

contributing to losses ranging from 15-100% in different agro-climatic zones of the country. Due to

prevalence of high humidity and temperature with frequent rainfall during the crop season the crop

become susceptible to a large number of diseases and insects pests and at the same time maize

suffers heavy yield losses owing to congenial environmental conditions for luxurious weed growth

due to wider row spacing and slow growth of crop at early stages. An important constraint is

achieving higher maize yield is losses caused due to various diseases, presence of insects pests

and weeds in fields which can not be neglected as these factors not only contribute to yield losses

but also aggravate the severity of various diseases and pests.

The major diseases of maize common in this region are, seed rot & seedling blight, leaf

spots & blights, downy mildews, banded leaf and sheath blight pre & post flowering stalk rots, rusts

& smuts. Of theses banded leaf and sheath blight (Rhizoctonia solani), Brown stripe downy mildew

(Sclerophthora rayssiae var. zeae) and Erwinia stalk rot (Erwiniz chrysanthemi pv. Zeae), are the

major ones. The maize stem borer (Chilo partellus) is the major insect pest attacking the crop

during the season along with several other minor pests occurring in low proportions. The

predominant weed species found in maize fields are Echinocloa colonum, Echinocloa crussgali,

Cyanodon dactylon, Eleusine indica Cyperus rotundus etc. Higher nitrogen applications also

enhance the pest population.

In view of the importance the incidence of various pests & disease the most appropriate

approach for reducing the losses is by evolving resistant varieties through resistant breeding. For

this purpose the maize genotypes obtained from different sources are screened and evaluated for

their performance for their utilization in breeding programme. Balanced applications of fertilizers

are always recommended as common practice for effective management of pests & diseases.

Several chemicals which are effective against R. solani have been tested for their

compatibility with the bio-agents and it has been found that chemicals like propaconazole tilt etc.

are compatible with most of the bio-agents. The use of bio-agents for the plant disease

management has been advocated to be more effective if combined with suitable effective chemical

as the later provide immediate protection from infection and gives some time for bio-agent to

establish on the applied plant region. Several bio-agents are known to be effective against the

pathogens of theses diseases. Trichoderma viride, Trichoderma harzianum, Gliocladium virens,

Pseudomonas fluorescens etc. have been found to be effective in reducing banded leaf and

sheath blight caused by R. solani and can be used for the management of disease.

There are several chemicals that have been found to be effective in reducing brown stripe


- 133 -

downy mildew of maize. Seed treatment with apron (metalaxyl) is highly effective in reducing

disease severity whereas Apron has also been found to be compatible with bio-agents such as Ps.

Fluorescens. Erwinia chrysenthemi pv. zeae causing stalk rot of maize is highly sensitive to

chlorine. Single application of calcium hypochlorite @ 25 kg/ha, successfully reduces the disease

and has also been found to be compatible with Ps. fluorescens. These recommended practices

can be integrated for integrated management of all the major diseases of maize so that higher

yield levels could be ensured.

Along with diseases the presence of insects pests and weeds in fields can not be

neglected as they aggravate the severity of various diseases either by acting as a carrier of

pathogen or by acting as an alternate or collateral host of the pathogen and may make the

environment conducive for disease development. Applying options for the management of insect

pests and weeds in disease management strategy could ensure higher yield levels. The borer

incidence can be checked by application of carbofuran granules (4-6 kg/ha) in whorls at the stage

of 15-20 days. Similarly weedicide application of atrazine 1.0 kg. a.i.) per ha. can effectively control

the weeds to a tolerable limit.

Thus, while developing a suitable management strategy it becomes very necessary to

consider the whole pest complex and imply it in the management strategy. Moreover it is present

day need to emphasize more on these methods, which are environmentally safe and eco-friendly.


- 134 -

Phosphate Solubilizing Bacteria and their Role in Crop Growth and Disease Management

Reeta Goel

Department of Microbiology, G.B.P.U.A. & Tech., Pantnagar-263 145 (Uttarakhand)

Introduction

Phosphorus (P) is one of the major nutrients to plants as well as micro -organisms

and being involved in major physiological processes, second only to nitrogen in

requirement. However, a greater part of soil phosphorus, approximately 95–99% is

present in the form of insoluble phosphates and hence cannot be utilized by the plants

(Vassileva et. al, 1998). Organic phosphorus constitutes a large proportion of the total

phosphorus in many soils. Inositol phosphate (soil phytate) is the major form of organic

phosphorus in soil, and other organic P compounds in soil are in the form of

phosphomonoesters, phosphodiesters including phospholipids and nucleic acids, and

phosphotriesters.

However, plants can only utilize P in inorganic form. Mineralization of most organic

phosphorus compound is carried out by means of phosphatase enzymes. The major

source of phosphatase activity in soil is considered to be microbial origin. To increase the

availability of phosphorus for plants, now a days large numbers of bacteria are used for

the conversion of soil organic phosphorus to the soluble inorganic form, which is known

as ‘Phosphate Solubilizing Bacteria’ (Asea, 1988; Singal, 1994). Some phosphate

solubilizing bacteria can also accumulate heavy metals, which are more beneficial to

eradicate heavy metal Phytotoxicity and growth promotion to plants (Katiyar and Goel,

2004).

Fig.1: Phosphorus cycle


- 135 -

Phosphate Solubilizing Microorganisms (PSMs)

Living plants can utilize only soluble inorganic phosphorus. The transformation of mineral

or organic phosphorus into soluble inorganic form is brought about by microbial action. Plants

utilize this available phosphorus and transform it into organic form. (Fig.1)

The last decade has seen a significantly increased knowledge about phosphate solubilizing

microorganisms. The metabolic activities of microorganisms (production of acids) solubilize

phosphate from insoluble calcium, iron and aluminium phosphates, in addition to it microbial

degradation of organic compounds like nucleic acids which releases phosphates. These

biochemical changes that take place in the soil prove that microorganisms perform numerous and

essential functions that contribute to the productivity of soil as listed below:

( i ) Conversion of organic phosphate in to insoluble inorganic phosphate:

Many soil microorganisms produce enzymes (phosphatases) that decompose different organic

phosphorus compounds (nucleoproteins and leciteins) in the soil. In this decomposition organic

phosphorus is converted in to phosphoric acid which combines with the soil bases to produce salt

of calcium, magnesium and iron. These salts are less soluble and thus less available to plants.

This mineralization occurs as follows:

(ii) Conversion of insoluble inorganic phosphates into soluble inorganic phosphates:

The solubility of phosphorus is mobilized by phosphoric acids. This is brought by microorganisms,

for example Pseudomonas, Mycobacterium, Micrococcus etc. These microorganisms produce

acids like sulphuric acid and nitric acid which ultimately help in mobilizing phosphorus. The action

of acids to convert insoluble phosphates into soluble once is generally called ‘Solubilization’.

Phosphate Solubilizing Bacteria (PSB):

Phosphorus is the second most important nutrient after nitrogen for the growth of plants and

microorganisms. Out of added Phosphorus fertilizer only 10-20% is available for the plants. The

Nucleoprotein Nuclein Nucleic acid Phosphoric acid

Insoluble mineral PO4

Lecitein

(Phospholipid) Glycerophosphoric acid esters Phosphoric acid

Insoluble mineral PO4


- 136 -

rest remains in the soil as insoluble phosphate in the form of rock phosphate and tri-calcium

phosphate. PSB significantly helps in the release of this insoluble inorganic phosphate and makes

it available to the plants. Some organic phosphate solubilizing bacterial genera are given below:

Azospirillim Staphylococcus Enterobactor

Azotobacter Xanthomonas Serratia

Arthrobacter Mycobacterium Citrobactor

Agrobacterium Pseudomonas Proteus

Actinomycetes Bacillus Klebsiella

Micrococcus Rhizobium

Role of PSB in Plant Growth

Bacteria are widely distributed in the rhizosphere of tropical and subtropical grasses and

sugarcane (Dobereiner et al., 1976). Phosphates, widely distributed in nature in both organic and

inorganic forms, are not readily available to plants in a bound state (Hayman, 1975). Many soil

bacteria are reported to solubilize these insoluble phosphates through various processes (Sperber,

1958; Illmer, 1992). A few reports have also indicated the P-solubilizing activity of some nitrogen

fixers (Will and Sylvia, 1990; Halder et al., 1991; Maheshkumar et al., 1999)

Many soil bacteria such as Pseudomonas, Rhizobium Enterobactor Bacillus etc. possess

the ability to solubilize insoluble inorganic phosphates and make them available to the plants

(Richardson and Hadobas, 1997). Production of organic acids i.e. lactic, gluconic, fumeric,

succinic & acetic acid by these organisms results in the solubilizing effect. These organisms are

also known to produce amino acids, vitamins and growth promoting substances like Indole Acetic

Acid (IAA) and Gibberellic Acid (GA), which results in better growth of plants.

Addition of these phosphate solubilizing organisms not only saves almost fifty per cent of

phosphorus fertilizers, it also optimizes the intake of phosphorus by the plants. Increases growth

and yield (10-20%) of a wide variety of crops such as mustard, maize, paddy, barley, oats, chick-

pea, soybean, groundnut and vegetables are among the most documented events.

1) Azotobacter

Azotobacter - a free-living bacterium that fixes atmospheric nitrogen, and has hence been

used as a very effective bio-fertilizer for several non-leguminous crops including fruits, vegetables

and medicinal plants. Azotobacter has the ability to produce growth-promoting substances such as

IAA, GA, vitamins and cytokinins, which have a beneficial effect on crop growth. Azotobacter is

also used for Wheat, Paddy, Maize, Barley, Jowar, Oat, Sugarbeet, Sugarcane, Cotton, Tobacco,

Sunflower, Mustard, Potato, Brinjal, Onion, Cauliflower, Tomato, Cabbage, Fruits, Vegetables,

Flowering plants, Forest and Medicinal plants.

2) Rhizobium

Rhizobium is an efficient plant rhizosphere colonizing bacteria. Which successfully reside


- 137 -

in the vicinity of the roots and benefit the plant through their growth promoting excretions as well

as bio-static properties. It produces growth-promoting substances that help plants in the optimal

uptake of nutrients and thus helps them grow efficiently and its efficiency in soil is also helpful to

controlling many seed-borne, air-borne and soil-borne diseases caused by bacteria and fungus.

Rhizobium is suitable for a wide range of crops including pulses, cereals, cash crops, medicinal

crops, fodder crops, oil crops, fruits and vegetable crops.

3) Pseudomonas

These bacteria are widely distributed in soil and water. Some Pseudomonas spp. are

reported as P solubilizer which solubilize the organic phosphate compounds and play an important

role in plant growth promotion e.g. Pseudomonas fluorescens (Vandna and Reeta, 2003), P.

putida (Manishi et. al., 2005) etc. Pseudomonas spp. is reported to suppress several major plant

pathogens.

4) Azospirillum

Azospirillm is an important organism which fixes atmospheric nitrogen as an associate

symbiotic nitrogen fixing bacterium. It secretes growth-promoting substances like Garlic acid and

cytokinins which enhance tillering, growth and vigour of the crops. Azospirillm is known for its N2

fixing ability at a higher pace than other micro-organisms. Azospirillum is also used for non-

leguminous crops. It has been found to be extremely beneficial for Wheat, Paddy, Maize, Bajra,

Sugarcane, Vegetables, and Medicinal plants.

Plant Growth Promotion and Microbe-Metal Interactions

Heavy metal toxicity to plants can be reduced by the use of plant growth promoting

bacteria, free living soil bacteria, these exert beneficial effects on plant development when they are

applied to seed or incorporated in the soil. There has been a tremendous work on P-solubilizing,

metal resistant, siderophore producing and plant growth promoting bacteria and their mutants.

Moreover, microbial gene pool has been developed which could be further exploited in heavy

metal contaminated sites for biodegradation and plant growth promotion purposes (Table 1).

Table 1: Important Bioinoculants available at GBPUA&T, Pantnagar

Strains Activities Crop Reference

KNP9 Sid+, Cd

r, Cu

r, Pb

r,

Growth Promotion Mung bean Tripathi, 2005

PRS 9 Hg

r,

Growth Promotion Soybean Gupta et. al., 2005

CRPF5,CRPF8

‘P’ Dynamics of soil Mung bean Das et al, 2003

NBRI 4014 Sid+ , P+, IAA+ Soybean Gupta et. al., 2002 & 2004

CRPF8 Sid+, Growth Promotion

Mung Bean Katiyar & Goel, 2004.

TH18 Cur ,‘P’ Solubilizer Black Gram Gupta et. al., 2004

CRPF1 Cold Resistant, Growth Promotion

Mung Bean Katiyar & Goel, 2003


- 138 -

CRPF7 Cold Resistant, ‘P’ Solubilizers

Mung Bean Das et. al., 2003

CD7 Metal Resistant, Osmophilic

Pulses Mittal et al, 2003.

CG1 Cur ,‘P’ Solubilizer Black Gram

Prameela et. al., 2002

GRS1 ‘P’ Solubilizer & Sid+ Soybean Mishra & Goel, 1999.

PRS1 Sid+ , Biocontrol Wheat Saxena et. al., 1999.

Katiyar and Goel (2004) found that siderophore overproducing mutant of Pseudomonas ATCC

13525 is a better bioinoculant than its wild counter part. Gupta et al (2005) developed mercury

resistant strains of P.fluorescens wild types (PRS9HGr, GRS1) through enrichment selection in

King’s medium. Further their root colonization studies were carried out, which showed that PRS9

was stable and resulted in significant increase in root and shoot fresh weight (P<0.05).

Table 2: Effect of inoculating fluorescent Pseudomonads and their mutants on root shoot

length of Glycine max after 21 days of inoculation

Strains/mutants Shoot (cm)a Root (cm)b

US 5.675±0.289 4.2±0.466

PRS9 (WT) 11.4±0.466 (100.8%) 5.8±0.439 (38.09%)

PSR9Hgr 11.6±0.605 (104.405%) 5.9±0.438 (40.47%)

GRS1(WT) 8.375±0.75 (47.57%) 9.25±288 (120.23%)

GRS1Hgr 7.2±0.864 (26.87%) 9.6±1.705 (128.57%)

Values in parenthesis are per cent increase or decrease as compared to control (US).

cMean±SD, n= 4; WT = wild type; US = uninoculated soil (control)

Both the mutants were found to be positive for indole acetic acid (IAA), “P” solubilization and

siderophore production (Table-3).

Table 3: Comparison of growth-promoting properties of fluorescent Pseudomonads

Strains IAAa ‘P’ solubilization b Siderophoresc

PRS9 7.84±0.14 184.00±0.181 1.245±0.143

GRS1 10.5±0.152 14.95±0.179 6.7±0.182

aµg ml-1 of IAA produced in a medium containing L-tryptophan.

bPhosphorus solubilized in µg ml-1 in NBRIP broth as described by Nautiyal (1999).

cµg ml-1 of siderophores produced in sodium succinate medium as described by Meyer and

Abdallah (1978).

Tripathi, (2005), isolated Pb and Cd resistant bacteria (strain KNP3) from Thermal Power

Plant, Kanpur and Kota. It was producing siderophore in sodium succinate media in high amount


- 139 -

(126.35 g/ml) (Table 4). It also solubilized “P” significantly (81g/ml).

Table 4: Metal tolerance level of strains KNP3 and its growth promotory properties.

Metal Tolerance (M) Growth promoting properties

Cd Pb Cu

Siderophore

(g/ml)

‘P’ solubilization

(g/ml)

KNP3 1092 1318 1318 126.34 0.52 81 14

Each value is mean of three independent replicates

Bioinoculation with KNP3 in lead polluted soil had increased shoot length (60.18%), root

length (13%), fresh weight (59.7%) and dry weight (59.7%) of plants in comparison to uninoculated

one (Table 5). Chlorophyll content of soybean plant was enhanced by KNP3 in presence of lead

which was comparable to the data when metal was absent (Fig. 1).

Table 5: Two way ANOVA indicating effect of KNP3 on Cd and Pb toxicity of mungbean in

autoclaved soil under green house at 30oC after 25 days

Shoot length

a (cm)

Root length

a (cm)

Wet weightb

(g) Dry

weightb

(g)

Chlorophyllc

(mg g-1

)

With

ou

t m

eta

l Mean (control)

27.0 5.30 1.6 0.42 3.5

Mean (treated)

31.4 (16.29)d

7.0 (32.0) 1.86 (16.25) 0.52 (23.8) 3.5 (0.0)

With

C

adm

ium

Mean (control)

22.9 4.35 0.99 0.22 1.72

Mean (treated) 28.9 (26.2) 5.25 (20.6) 1.55 (56.6) 0.35 (59.0) 2.83 (64.5)

Critical difference at 5%

1.76 1.62 (nse) 0.812 0.82 0.62

With

L

ea

d Mean

(control) 24.7 3.91 0.74 0.18 2.38

Mean (treated)

27.9 (12.95) 5.85 (49.61) 1.25 (8.9) 0.24 (33.3) 3.2 (34.45)

Critical difference at 5%

2.84 1.62 0.66 0.23 0.55

Similar is the case with Cd contaminated site, KNP3 had increased shoot length (41.86),

root length (67.18), fresh weight (71.7) and dry weight (77.3) of plants in comparison to

uninoculated one (Table 5).

Role OF PSMs in Plant Disease Management

One of the cheapest hazard-free and eco friendly effective method of modifying soil environment is

amendment of soil with decomposable organic matter or using plant growth promoting

microorganisms. Sun and Huang (1985) had rightly observed that continuous extensive agricultural

practices that depend heavily on use of chemicals have resulted in loss of organic matter, an increase

in acidity, and accumulation of toxic elements in cultivated soils creating an environment favorable for


- 140 -

development of certain soil, born pathogen. The reduction in common scab of potato (S. scabies) by

green manuring through prevention of the buildup of inoculums was the first report of organic

amendments as a means of disease suppression. Since this observation of Sanford (1926), numerous

reports have appeared regarding the beneficial effects of organic and inorganic amendment of soil.

Phosphorus Deficiencies and its Remedial Measure

Fruit trees and crop plants suffer nutritional disorder due to inadequate supply or excess of certain

minerals. Antagonistic or synergistic interactions among mineral elements have also been reported in

soil or in plant system. The macronutrients are indispensable for optimal growth and development and

which plants absorb primarily through roots.

Phosphorus is an important macronutrient required in larger quantity for normal plant growth and

reproduction. Due to phosphorus deficiency plant grows poorly and the leaves are bluish-green with

purple tints. Lower leaves sometimes turn light bronze with purple or brown spots; shoots are short,

thin upright and spindly. These deficiencies cause a reduction in plant growth through slower leaf

production. Older leaves exhibit marginal chlorosis along with purplish brown flecks, which gradually

increase. Chlorosis spread inward from midrib, sometimes leaving areas of healthy green tissues.

Necrosis of tissue leads to withering of leaves and breaking petioles at the pseudostem. The distance

between leaves on the pseudostem is shortened giving a ‘rosette’ appearance. Younger leaves do not

exhibit symptoms.

Conclusion

Thus we could suggest that there as a tremendous potential associated with microbes

having high ‘P’ solubilization activity. Moreover, along with wild types metal resistant mutants could

be developed for the high yield of diseased free and healthy crops.

REFERENCES 1. Asea, P. E. A., Kucey, R. M. N. and Stewart, J. W. B., Soil Biol. Biochem., 1988, 20,

459–464.

2. Cunningham, J. E. and Kuiack, C., Appl. Environ. Microbiol., 1992, 58, 1451–1458.

3. Dobereiner, J. and Day, J. M., Proc. Of 1st Int. Symp. on Nitrogen Fixation (eds. W. E. Newton and C. J. Nyman), Washington State University Press, 1976, 518.

4. Gupta A, Rai V, Bagdwal N and Goel R.,. Microbiological research, 2005, 160(4):385-388.

5. Gyaneshwar, P., Naresh K. G. and Parekh, L. J., Curr. Sci., 1998, 74, 1097–1099.

6. Halder, A. K., Mishra, A. K. and Chakrabarthy, P. K., Indian J. Exp. Biol., 1991, 29, 28–31.

7. Halder, A. K., Mishra, A. K. and Chakrabarthy, P. K., Indian J. Microbiol., 1990, 30, 311–314.

8. Hayman, D. S., in Soil Microbiology, Butterworths, London, 1975, pp. 67–92.


- 141 -

9. Illmer, P. and Schinner, F., Soil Biol. Biochem., 1992, 24, 389–395.

10. Jones, D. L. and Darrah, P. R., Plant Soil, 1994, 166, 247– 257.

11. Katiyar, V. and Goel, R., Plant Growth Regulation, 2004, 42 (3), 239-244.

12. Katiyar V and Goel R, J. Microbio & Biotechnol., 2004, 14 (4):653-657.

13. Kucey, M. N., Janzen, H. H. and Legett, M. E., Adv. Agron., 1989, 42, 198–228.

14. Maheshkumar, K. S., Krishnaraj, P. U. and Algawadi, A. R., Curr. Sci., 1999, 76, 874–875.

15. Manishi, T., Hitendra, P.M., Yogesh, S., Jean, M.M. and Reeta, G., Current Microbiology, 2005, 50, 1-5.

16. Newton, L. C., Paulino V. T., Veasey, E. A. and Leonidas, F. C., Leucaena Res. Rep., 1992, 13, 10–12.

17. Richardson, A.E. and Hadobas, P.A. Biotechnol.,1997 Adv. 17, 319-339.

18. Singal, R., Gupta, R. and Saxena, R. K., Folia Microbiol., 1994, 39, 33–36.

19. Sperber, J. I., Aust J. Agric. Res., 1958, 9, 778–781.

20. Sun, S.K. and Huang, J.W., 1985 Formulated soil amendment for controlling fusarium wilt and other soil-born diseases, plant Dis., 77, 420

21. Toro, M., Azcon, R. and Barea, J. M., Appl. Environ. Microbiol., 1997, 63, 4408–4412.

22. Vandana, K. and Reeta, G., Microbiol. Res.. 2003, 158, 163-168.

23. Vassileva, M., Vassilev, N. and Azcon, R., World J. Microbiol. Biotech., 1998, 14, 281–284.

24. Will, M. E. and Sylvia, M., Appl. Environ. Microbiol., 1990, 56, 2073–2079.

25. Yadav, K. S. and Dadarwal, K. R., in Biotechnological Approaches in Soil Microorganisms for Sustainable Crop Production (ed. Dadarwal, K. R.), Scientific Publishers, Jodhpur, 1997, 293–308.


- 142 -

Plant Parasitic Nematodes– A Major Constraint to Agricultural Productivity and their Management

Akhtar Haseeb

Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh

Nematodes are the most numerous multi-cellular, triploblastic, bilaterally symmetrical,

unsegmented pseudocoelomate animal on the earth with the exception of Arthropoda, has

enormous impact on human welfare, both directly and indirectly through their effect on agriculture

as a parasite of animals and plants. Despite their low evolutionary status, they are found in every

kind of environment. They are highly diverse in habitats such as forest to desert soils, fresh water,

oceans, high mountains, wet banks of streams and lakes, and even in the floor of the arctic and

Antarctic. Plant parasitic nematodes constitute only 10% of the total nematode species, yet a plant

is often attacked by one or more species. Usually, they are found in and around the roots of their

host plants or in the stems, leaves and seeds.

Plant parasitic nematodes must be addressed in crop production and integrated pest

management (IPM) system if agriculture is to meet the world demands for increasing food and

fibre production. On a worldwide basis, annual crop losses due to nematode damage have been

estimated to average 12.3 percent (Sasser and Freckman, 1987), amounting to some US$ 77

billion annually.

Generally plant parasitic nematodes produced recognizable disease symptoms on an

appropriate host and when they interact with other pathogenic organisms, the disease picture

drastically altered and the damage becomes many fold and some times the crops destroyed

completely.


- 143 -

I. Different stages of Plant parasitic nematodes

.

II. Above ground symptoms on various crops caused by root-knot nematode

(A) & (B) Chickpea, (C) Mungbean, (D) lentil, (E) mentha and (F) chilli

Female of Heterodera cyst having eggs with hatching of juvenile

(A) Egg, (B) Second stage juvenile, (C) Mature female of root-knot nematode (Meloidogyne incognita); (D) Cyst with eggs, (E) Second stage juvenile, (F) Mature female of cyst nematode (Heterodera cajani) attach with root; (G) Mature female of reniform nematode (Rotylenchulus reniformis); (H) Female of rice root nematode (Hirschmaniella oryzae); (I) Female of Bursaphelenchus xylophilus

A B

C D

A B

D

C

G

F

H

E

I

E F


- 144 -

III. Under ground symptoms on various crops caused by root-knot nematode (A) Carrot, (B) Black Henbane (C) Chickpea

A

IV. Symptoms of Pratylenchus thornei infection on aerial and underground parts of Mentha arvensis

V. Symptoms of Tylenchulus semipenetrans infection on underground parts of citrus

A B C A


- 145 -

A number of factors such as the nematode species, the size of nematode population,

susceptibility of the host plant, environmental factors and the presence of other organisms govern

the damage caused by plant parasitic nematodes. Plant parasitic nematodes affect the production

and economy of crops in diverse ways such as: (i) reduction in quality and quantity of crops, (ii)

need of additional fertilizers, water and application of nematicides, and (iii) impediment of

production and trade by phytosanitory regulations.

Currently most nematode management programmes focus on tactics involving the

reduction of the initial nematode population density and/or the suppression of their reproduction

during the cropping season. Most nematode management tactics also have the inherent feature of

limiting damage associated with the target crop. With the diminishing availability of a single

strategy of tactics for nematode management, a combination of two or more compatible tactics in

an integrated system is becoming more critical. Various methods have been tried for the

management of these noxious pests viz., cultural, physical, chemical, regulatory, use of resistant

varieties, biological and integrated pest management (IPM) to reduce nematode population

densities and improve productivity of various crops.

1. Cultural Methods

The nematodes can be managed to below the economic threshold level to a large extent

by cultural practices such as crop rotation, fallowing, flooding, ploughing, use of disease free

propagating materials, prevention of spread, time of planting, cropping and manuring/organic

matter amendment etc. From an ecological point of view these methods are quite useful but

unfortunately some of them have one or the other kind of limitations.

2. Physical Methods

The physical methods aim at the eradication of nematodes through various means viz., soil

solarization, steam sterilization, hot water treatments, radiation treatments, washing processes

and seed cleaning etc. Physical methods though very effective on a small scale and are of little

value to the farmers. These methods may be more effective when combined with other suitable

methods.

3. Chemical Methods

Chemical methods include the use of fumigant and non-fumigant nematicides for the

control of plant parasitic nematodes. Among fumigants, the DD, EDB and DBCP are very effective

soil fumigants. However, most of non-fumigant nematicides belong to carbamate and organo

phosphate group. Although, chemical control is the most effective mean of nematode management

but now most of the chemicals are banned due to the fact that they contaminate ground water and

hazardous to human, environment, live stock and also to the beneficial microorganisms and also

they are not cost effective to crops.

4. Resistant Varieties

This is safest and most effective method of disease control. Once successful, it eliminates


- 146 -

expenses for chemical or other methods. Growing resistant varieties of crops in crop rotation is

economical for the farmer in reducing nematode populations gradually in the infested fields. The

use of nematode resistant cultivars should be considered complementary method of control and

not as competitive measures.

Table 2. Resistant varieties/cultivars of important crops against plant parasitic nematodes

Crop Resistant variety/cultivars Plant parasitic nematode

Tomato Hisar Lalit, N-1, N-2 Meloidogyne incognita

Brinjal IC 111023, IC 285142 M. incognita

Chilli Indira Chilli, CO 4 M. incognita

Pigeonpea Paras, HDL-40-1 M. Javanica & Heterodera cajani

SKNP-202, Pusa-2005-02 M. incognita

Chickpea C-17, C-20 M. javanica

Pea FP-26 M. incognita

Lentil Le-26 M. incognita

Mungbean G-2-06 M. incognita

Urdbean G-4-06, G-02-06 M. incognita

Groundnut OG-52-1, M-197 M. javanica

ISSKI-05-01, ISKI-05-02 M. arenaria

Rice HRI – 152 M. graminicola

5. Regulatory Methods

The dissemination of nematodes, like other pests, can be checked effectively by regulatory

control methods like quarantines. Plant quarantine may be defined as an endeavor to prevent or

limit the spread or introduction of dangerous or disease causing organisms. The regulatory control

however, provide a check only on the introduction, or if already introduced on further spread of

some pests and pathogens by it can not govern the activity of common nematode species that are

already well established in any area of the country.

6. Biological Control

Biological control of nematodes is a distinct possibility for future and it can be successfully

exploited in modern agriculture. The discovery of new biocontrol agents and demonstration of their

impact in reducing disease incidence and severity has opened new avenues for practical

applications in agriculture and for promoting environmental safety. Biological control includes the

use of predacious or parasitic organisms such as protozoans, viruses, nematodes, tardigrades,

terbullarians, collembolans, mites, enchytraeids, bacteria and fungi, etc. Among them, fungi and

fluorescent Pseudomonas constitute the most significant group of nematode antagonists which


- 147 -

has great potential for the management of the important plant parasitic nematodes in field

conditions.

7. Integrated Pest Management

Integration of two or more means for the management of pest and diseases is not a new

concept as some of its methodology is quite ancient. The relatively new aspects are its application

in scientific experimentation and research for evolving an integrated and economically feasible

approach. For achieving this, a clear understanding of the biology of crops, pests and their natural

enemies is essential. In recent years, efforts are being made to restrict the use of chemicals to

protect the environmental degradation, the use of non-chemicals means of management of plant

parasitic nematodes now being advocated much while developing the integrated pest

management strategies.

Conclusion

Each combination of nematode and host is different. As the nematode population density

reaches at certain level, the host crop yield suffers greatly. Some host support faster population

increases than others. Environmental conditions can also affect the relative dangers posed by

nematode populations. As we begin to develop a better understanding of the complex ecologies of

soils and agricultural ecosystems, more strategies for cultural and biological control of nematodes

will be developed. The trick will be fine – tuning the general strategies to the unique ecology,

equipment and financial situation of each farm. Current experience suggests that biological control

agents will not replace the use of nematicides but integration with other control measures could

play an important role in the development of integrated control strategies in both developed and

developing agriculture. The urgent need to reduce the dependence on nematicides should provide

the necessary impetus for the considerable amount of research and development still required to

ensure the successful use of such agents.


- 148 -

New Generation Fungicides

T.S. Thind Department of Plant Pathology, Punjab Agricultural University, Ludhiana-141004

Fungicides are in common use for the control of plant diseases the world over since 19th

century and in many cases have become an integral component of our crop production system.

Despite certain drawbacks, these are considered to play a significant role in containing losses due to

plant diseases in the coming years.

The development of fungicides has passed through several stages. Generally, the type of

materials developed corresponded with the knowledge of disease etiology and also the chemical and

biological properties of the compounds. Initially, simple inorganic chemicals were put to use, but as our

understanding of pathogenic processes increased, more complex organic compounds were developed

with enhanced efficacy. The agrochemical companies became more active after the second world war

and realizing the potential of fungicide use in crop protection developed several classes of versatile

non-systemic, protectant fungicides like sulphur, copper-based, dithiocarbamates, phthalimides,

crotonates, organotins, dodine, quintozene etc. between 1930s and 1950s. These were unable to

control pathogens already established within the plant tissues. The introduction of systemic fungicides

in late 1960s caused a revolution in plant disease control and several damaging diseases, which were

difficult to be controlled by earlier non-systemic protectant fungicides, could be effectively managed by

the use of these systemic compounds. In late 1960s and 1970s, several new classes of fungicides,

mostly systemic in nature, such as oxathiins, 2-aminopyrimidines, benzimidazoles, morpholines,

dicarboximides, phenylamides, phosphorothiolates, phenylamides, alkyl-phosphonates were

introduced and development of their related compounds with improved properties continued thereafter

in 1980s. These fungicides were more potent and specific in their activity and were effective at much

lower dose rates than the earlier surface protectants.

While the development of non-systemic multisite action protectant fungicides became almost

static after 1970, new groups of site specific systemic fungicides continued to emerge and still new such

molecules are being discovered every year. Presently, more than 150 fungicidal compounds falling in

more than 50 mode of action groups are used the world over to manage diverse diseases (Thind, 2006).

New generation fungicides (Novel modes of action, 1991-2000)

Strobilurins

Of the new compounds, strobilurins (also called β – methoxyacrylates) are the most

important and are effective against a diverse range of plant pathogens and diseases (downy

mildews, powdery mildews, Phytophthora and Alternaria blights, rusts, apple scab, Rhizoctonia

infections, Septoria and Cercospora leaf spots, rice sheath blight and blast etc.) caused by

Oomycetes, Ascomycetes, Basidiomycetes and Fungi Imperfecti (Jensen, 1997). These

compounds are analogues of strobilurin-A originally obtained from Strobilurus tenacellus, a wild

mushroom growing in temperate forests. Their synthesis was initiated by BASF and Zeneca (now


- 149 -

Syngenta) to prepare analogues of strobilurin-A possessing desired fungitoxicity, good light

stability and systemic properties without phytotoxicity. The first analogue was registered for large

scale applications against various diseases in 1996 which was soon followed by kresoxim methyl

and trifloxystrobin. Another strobilurin analogue metaminostrobin was developed in Japan in 1998

for use against rice diseases (Koizumi, 1998). Their fungicidal activity results from the prevention

of electron transfer between cytochrome b and c1 in complex III of the mitochondrial electron

transfer chain (Leroux, 1996). These are also effective against fungal strains having developed

resistance to other groups of fungicides.

Oxazolidinediones

Famoxadone, a representative of this group, is a broad spectrum fungicide for use in fruits

and cereals. It shows remarkable activity against Phytophthora infestans and Plasmopara viticola.

It also controls cereal pathogens like Puccinia, Septoria and Pyrenophora spp. The compound

inhibits the activity of ubiquinol cytochrome c oxido-reductase at complex III. It mainly controls

diseases through protectant action with significant translaminar movement. Lately, famoxadone

has been introduced in combination with cymoxanil (KX007 – 42 SC) to enhance disease control

and as resistance management step.

Anilinopyrimidines

These are broad spectrum novel fungicides having a potential use in a variety of crops.

Mepanipyrim and pyrimethanil possess remarkable activity against Botrytis cinerea on grapevine

and other fruits and Venturia inaequalis on apples (Daniels et al., 1994). Cyprodanil, another such

compound, has additional activity against Pseudocercosporella herpotrichoides, Erysiphe

graminis, Helminthosporium gramineum, Pyrenophora teres and Septoria nodorum on cereals.

These compounds are considered to inhibit methionine biosynthesis.

Phenylpyrroles

These compounds were developed from secondary metabilites produced by Pseudomonas

pyrrocina having fungicidal properties. Of the two commercial fungicides, fenpiclonil is used as seed

dressing while fludioxanil is applied as seed dressing and foliar spray against Botrytis cinerea (Gullino

et al., 2000). These fungicides have a broad disease control spectrum but are inactive against

oomycete pathogens. Though primary target is not yet certain, they appear to affect glucose

phosphorylation in target fungi. Another phenylpyrrole pyrrolnitrin is unsuitable for use in practical

disease control because of its unstability in light.

Phenoxyquinolines

These were introduced in 1996 for control of powdery mildews in cereals and other crops.

Quinoxyfen (DE-795) shows marked activity against Erysiphe graminis (cereals) and Uncinula

necator (grapevine) and is a systemic protectant in action providing long term control (Longhurst et

al., 1996). It has vapour phase redistribution and inhibits spore germination and appressorium

formation by affecting dihydro – orotate – dehydrogenase in pyrimidine biosynthesis pathway. It

has also shown good activity against Botrytis cinerea in different crops.


- 150 -

Spiroketalamines

Spiroxamine is a novel ergosterol biosynthesis inhibitor introduced in 1996 and is particularly

effective against powdery mildew of cereals and grapevine (Dutzmann et al., 1996). Apart from

inhibiting ∆14 reductase, it has additional activity against ∆8,7 isomerase, squalene synthase and

squalene cyclase and hence shows cross resistance to morpholine and piperidine compounds.

Other compounds in this period

Mefenoxam (Metalaxyl-M), an enantiomer of metalaxyl, was introduced by Syngenta in

1996 and is considered more potent than metalaxyl against oomycete pathogens (Nunninger et

al., 1996). Carpropamid (KTU 3616), another MBI compound, was developed by Bayer in 1997 for

potential use against rice blast (Koizumi, 1998) and is a scytalone dehydratase inhibitor.

Recently developed fungicides (2001-2007)

Of late, some new compounds have been developed most of which have been introduced

for use against oomyceteous pathogens.

Benzamides

Two benzamide compounds viz. fluopicolide and zoxamide have been developed recently

for use against diseases caused by oomycete pathogens such as downy mildew and late blight.

These show their activity by interfereing with microtubule skeleton similar to benzimidazoles

though at a different step (Egan et al., 1998). These are generally used in combination with

mancozeb. Fluopicolide has recently been formulated with propamocarb for better action and

modifies the cellular localization of a spectrin like protein (Toquin et al., 2007).

Valinamides

Two compounds of this group, also known as amino acid amide carbamates, viz. iprovalicarb

and benthiavalicarb have been introduced recently by Bayer and Kumiai Chemicals in 2002 and

2003, respectively. These are quite effective against potato late blight and grape downy mildew

(Reuveni, 2003). Combination of iprovalicarb with propineb (Melody Duo) has been introduced to

increase its disease control capability and as a measure to check resistance build up.

Imidazolinones

Also known as imidazoles, this group is represented by fenamidone. Introduced by Bayer

Cropscience in 2003 for use against oomycete pathogens, fenamidone has been commercialized in

combination with mancozeb (Secure 68 WG) for the control of downy mildew and late blight.

Other compounds developed in the recent years for use against oomycete pathogens are

cyazofamid (cyanoimidazoles, ISK Biosciences), mandipropamid (Mandelamides, Syngenta),

ethaboxam (Thiocarbamates, LG Biosciences) (Huggenburger et al., 2005). Similarly, strobilurin

compounds developed later up to 2006 are pyraclostrobin, picoxystrobin, fluoxastrobin and

dimoxystrobin and have the potential to control diverse fungal pathogens.

Few more compounds with different chemistry and activity have also been developed recently.

These include tolyfluanid (Phenylsulfamides, Bayer) for Botrytis and powdery mildews, metrafenone

(Benzophenones, BASF) for cereal powdery mildew, boscalid (Anilides, BASF) for Septoria, eye spot


- 151 -

and Fusarium scab in wheat, cyflufenamid (Amidoximes, Nippon Soda) for powdery mildews,

epoxyconazole (Triazoles, BASF) for sigatoka of banana, ipoconazole (Triazoles, Crompton Corp.) for

seed treatment in cereals and prothioconazole (Triazolinthiones, Bayer) for wheat foliar diseases.

Advantages of new compounds

The new compounds which have originated from different approaches such as traditional

random screening and from natural products are expected to provide better disease control options,

are ecologically safe and show good efficacy at much lower doses. These require fewer ttreatments

per season compared to earlier compounds. Since they possess novel modes of action, there are less

chances of resistance development or cross resistance to previous fungicides. These are easily

degradable and pose less threat to the environment. There is significant improvement in their

formulations and are more safe to the crops.

REFERENCES

1. Daniels, A., Birchmore, R.J. and Winter, E.H. (1994). Activity of pyrimethanil on Venturia inaequalis. In : Proceedings of Brighton Crop Protection Conference – Pests and Diseases, Vol. 2, BCPC, Farnham, pp. 525-532.

2. Dutzmann, S., Berg, D., Clausen, N.E., Kramer, W., Kuck, K.H., Ponzen, R., Tiemann, R., Weissmuller, J. (1996). KWG 4168 : a novel foliar fungicide with a particular activity against powdery mildew. In : Proceedings of Brighton Crop Protection Conference – Pests and Diseases, Vol. 1, BCPC, Farnham, pp. 47-52.

3. Gullino, M.L., Leroux, P. and Smith, C.M. (2000). Uses and challenges of novel compounds for plant disease control. Crop Protection, 19 : 1-11.

4. Huggenburger, F., Lamberth, C., Iwanzik, W. and Knauf-Beiter, G. (2005). Mandipropamid a new fungicide for oomycete pathogens. BCPC International Congress on Crop Science and Technology, 31 October – 2 November, 2005, Glasgow, UK.

5. Jensen, H. (1997). Amistar – a broad spectrum fungicide. Proc. 14th Danish Plant Protection

Conference – Pests and Diseases, 8 : 59-71.

6. Koizumi, S. (1998). New fungicide for use on rice in Japan. 7th Inter. Cong. Plant Pathology,

Edinburgh, Scotland, 9-16 August, 1998. Abstract No. 5.6.3S.

7. Leroux, P. (1996). Recent developments in the mode of action f fungicides. Pesticide Sci. 47 : 191-197.

8. Longhurst, C., Dixon, K., Mayr, A., Bernhard, U., Prince, K., Sellars, J., Prove, P., Richard, C., Arnold, W., Dreikorn, B. and Carson, C. (1996). DE 795 – a novel fungicide for the control of powdery mildew. In : Proceedings of the British Crop Protection Conference 1996 – Pests and Diseases, Vol. 1, BCPC, Farnham, pp. 27-32.

9. Nunninger, C., Watson, G., Leadbitter, N., Ellgehausen, H. (1996). CGA329351 : introduction of the enantiometric form of the fungicide metalaxyl. In : Proceedings of the British Crop Protection Conference 1996 – Pests and Diseases, Vol. 1, BCPC, Farnham, pp. 41-46.

10. Reuveni, M. (2003). Activity of new fungicide Benthiavalicarb against Plasmopara viticola and its efficacy in controlling downy mildew in grapevines. European Jour. Plant Pathol.109 (3) : 243-251.

11. Thind, T.S. (2006). Significant achievements and current status : fungicide research. In : One Hundred Years of Plant Pathology in India – An Overview, S.S. Chahal, R.K. Khetarpal, T.S. Thind (Eds), Scientific Publishers India, Jodhpur, pp. 267-306.

12. Toquin, V., Gamet, S., Bajra, F., Sirven, C., Jundel, J-L., Schmitt, F. and Beffa, R. (2007). Modification of the cellular localization of a spectrin-like protein by fluopicolide. A new mode of action for an anti oomycete fungicide.International Reinhardsbrunn Symposium, Friedrichroda, Germany.


- 152 -

Advances in the Management of Sheath Blight Disease of Rice

A.P. Sinha and Saurabh Tripathi Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

Sheath blight of rice is one of the major production constraints of rice in most of the rice

growing areas in India. Intensive and changed cultivars practices have intensified the severity of

the disease. Several estimates of yield reduction due to sheath blight have been reported.

Cultivars like. "Mahsuri" suffered as much as 69% reduction in grain yield due to sheath blight

epidemic in West Godawary district of Andhra Pradesh during 1985.

The fungus causing sheath blight is Rhizoctonia solani Kuhn. Telemorph is identified in

Thanatephorus cucumeris (Frawk.) Donk. Initial symptoms of sheath blight are lesions on sheaths

of lower leaves when plants are in the late tillering or early internode elongation stage of growth.

These lesions appear 0.5 to 3 cm below. The symptoms appear as circular, oblong or ellipsoid,

green grey, water soaked spots about 1 cm long. They enlarge to approximately 1 cm in width and

2-3 cm in length. Lesions on the upper portion of plants coalesce to cover entire leaf sheaths and

stems. Sclerotia, initially white but turning brown at maturity, are produced superficially on or near

the infected tissue after 6 days Disease development is most rapid in the early heading and grain

filling growth stages. Plants heavily infected at these stages produce poorly filled grain.

Information on the integrated management of sheath blight to minimize the yield losses are

discussed below based on varietal resistance, suitably tailored cultural practices, judicious use of

effective chemicals on the basis of surveillance, and use of biological agencies.

Varietal resistance

Cultivation of resistant or tolerant varieties would be the most effective and economical

method to control sheath blight. Commercial variety resistant to sheath blight is rare; however, a

few moderately resistant cultivars are available. This has been observed in Taiwan, Korea, and

Philippines and in Assam (India) (Roy, 1993). Sheath blight may be severe on semi dwarf varieties

because of short distance between waterline (site of infection) and panicles (Marchetti, 1983).

Morphological features imparting resistance. Bharti, CR 1014, Nalini, Pankaj, Ratna, Tetap were

found to be less susceptible to sheath blight.

Cultural practices:

Field sanitation by destroying grasses and other collateral hosts and burning infected straw

and stubbles reduce infection. Papavizas and Lewis (1979) suggested burial of residue of the

previous crop to a depth of 20-25 cm by a mould board plough and then application of carboxin.

Introduction of minimum tillage which merely stirs the soil rather than inverting it improves

condition for survival of sclerotia. Transplanting rice seedlings at spacing of 25 x 25 cm against 15

x 15 cm, the favourable effect of high N application in disease development could be reduced

(Roy, 1978). Incorporation of oilcakes and some green manuring crops, particularly Sesbania

aculeata (dhaincha) and green gram reduced survival of R. solani. Roy (1985) reported loss of


- 153 -

survival of sclerotia in root zone of S. aculeata. Application of micro nutrients such as borax, zinc

sulphate, copper Sulphate, and ferrous Sulphate at 0.05% with two foliar sprays reduced the

disease and increased the grain yield in Tamilnadu (Kanniyan and Prasad, 1979). Oilcake saw

dust and rice husks have been found to be very effective in suppressing sheath blight (Rajan

(1980). Low disease incidence was reported with increased addition to potash (Khan and Sinha,

2005). Soil typed may also influence the incidence of the disease, especially if this is related to

moisture content. In Japan, sheath blight is more prevalent in drained rice field than in upland

fields and is less frequent in light clay soil than in clay loam and loam (Verma et al., 1978).

Biological approach

Biological control of R. solani could be achieved by either promoting the native antagonists

to reach a density sufficient to suppress the pathogen or by introducing alien antagonists. Although

some of the earlier work was related to promoting the native antagonists by using organic

amendments or other cultural practices, in recent years considerable success has been achieved

by introducing antagonists to soil or to specific court of infection and also by seed treatments

(Singh et al, 2003).

Antagonistic effects of Bacillus subtilis, B. cereus, Enterobactor sp., Pseudomonas

fluorescens, P.putida and P. aureofaciens on the growth of R. Solani in vitro have been

demonstrated (Gnanamanickam and mew, 1990; Lee et al., 1990, Singh and Sinha, 2004). Seed

bacterization with fluorescent and non-fluorescent bacteria suppressed the sheath blight disease

and protected the plant from infection. Subsequent planting after the first crop, in which seeds

were treated with bacteria, on the same soil also showed reduced disease severity (Mew and

Rosales, 1986). Pseudomonas aureofaciens controlled rice sheath blight in early growth stages

better than did P. putida and P.fjluorescens when rice seeds were coated with these antagonists

(Lee et al., 1990, Singh and Sinha, 2005). When a suspension of B. cereus was sprayed on

inoculated rice plants, 43.8% control of the disease were obtained compared with the inoculated

but unsprayed control (Lee et al., 1993), demonstrated that certain chemical soil stresses like

acidic pH and boron toxicity did not appear to be limiting factors for the biological control of

sheath blight in low land rice, while alkaline pH and zinc deficiency in soil did not influence

disease suppression by bacterial antagnostis. Gnanamanickam et al, 1989, Singh and Sinha,

2007) Effective strains of Pseudomonas fluorescens inhibited mycelial growth of R. solani,

affected sclerotial viability in vitro and protected rice seedlings from infection by R. solani in

glasshouse tests (Singh and Sinha, 2007). It has been demonstrated that P. fluorescens isolated

from rice leaves was found best in managing sheath blight as compared to other isolates. (Singh

and Sinha, 2004).

Various fungi such as Aspergillus niger, A. terreus, Glioc/adium virens, Trichoderma spp,

inhibited mycelial growth of Rhizoctonia solani in vitro (Khan and Sinha, 2007, Vaish and Sinha,

2004, 2006). In pot culture, soil amendment with T. aureoviride reduced the incidence of sheath

blight in rice (Manian and paulsamy, 1987). Two fungal antagonists (G. virens and T


- 154 -

longibrachiatum) applied to the soil as wheat bran dust preparation survived well in soil and

reduced the pathogen population. When the antagonists were supplemented with organic

substrates, an increase in the colony farming units of the antagonists and a marked reduction in

the pathogen survival was noticed (Baby and Manibhushan Rao, 1993). In pot tests, applications

of spore suspensions of A. terreus reduced infection by R. so/ani, particularly when plants were

treated before inoculation with sclerotia of the pathogen (Gogoi and Roy, 1993). Aspergillus

terreus reduced incidence of sheath blight on rice culture IR 50 in pot test. Fungal antagonist was

more effective in suppressing the disease in soil having pH of 7.2 comparison to soil having pH 5.2

( Khan And Sinha, 2005).

Botanical management

Inhibitory effect of neem oil cake, leaf extracts of A. indica, O. stramonium, O. sanctum, P.

longifolia, V. rosea Allium cepa, Azadirachta indica, Caesalpinia pulcherrima, Eucalyptus globules,

Calotropis gigantean, lpomoea carnia (carnea), Lawsonia inermis, Ocimum sanctum (tenuiflorum),

Parthenium hysterophorus, Piper betel (betle), Pongamia glabra (pinnata), Prosopis juliflora and

Thevetia peruviana has been observed on R. solani, It was also reported that the inhibitory effect was

fungistatic rather than fungicidal. (Khan et al., 1973;Shivpuri et al. 1997; Kurucheve et al. 1997). .

Prashad et al. (1998) studied survival of sclerotia of R. solani in rice soils amended with oil cakes and

green leaf manures. The effect of oil cakes (neem cake, groundnut cake, sesame cake) and 3 green

leaf manure viz. Colotropis sp., Crotalaria sp. and Phaseolus sp. On sclerotial survival of R. solani

(causing rice sheath blight) was studied in 3 rice land sols in Bapatla, Andhra Pradesh, India. Neem

cake and Calotropis were the most effective in affecting the survival of sclerotia in soil.

Of the ten botanicals screened in vitro against R. solani, cold water extract of Garlic was

found most effective in inhibiting mycelial growth completely (100%). Methanol extract of Garlic

and Ginger resulted in 100% inhibition of mycelial growth at all the concentrations tested. Neem

was next in order to effectivity against R. solani. Of the three commercial formulations, Achook

was found best in inhibiting mycelial growth of the pathogen (70%). Garlic and Ginger was found

superior to all other botanicals in inhibiting sclerotial production. Foliar spray with Achook was

found best in reducing sheath blight severity (33.0%) which is followed by Tricure (23%) and

Biotas (21.29%). Among botanicals, Achook had shown superiority in increasing grain yield i.e.

15.98% (Chalvalria, 2006). The use of botanicals offers a cheaper and environmentally safer

alternative to fungicide for foliar spray against sheath blight of rice.

Chemical control

Several fungicides, antibiotics and also certain herbicides were found best in controlling the

disease. Application of Arasan and Quintozene @ 100 g/100 kg to seed reduced sheath blight and

increased germination percentage (Marcos, 1975). Four antibiotics - 2 developed in Japan viz.

Validamycin and polyoxin, and 2 developed in china viz., Jingganycin and Chingfengmeisu have

been found effective against sheath blight (Gangopadhyay and Chakraborti, 1982; Singh et al, 2003).

Validamycin A and Aureofungin have given good result in India. Sclerotia viability was reduced by


- 155 -

applying herbicides particularly paraquat and Thiram and thiobencarb under field conditions (Pathak,

1990). Fungicides viz., hexaconazole, propiconazole Folicur and Thiafluzamide were found highly

effective against R. solani (Vaish and Sinha, (2003). Kannaiyan and prasad (1979) concluded that

soil application of edifenphos, kitazin and carboxin can completely inhibit sclertoial gennination and

inactivate the mycelium of R. so/ani. Quintozene, thiabendazole, Edifenphos, cholorothalonil and

chloroneb completely arrested growth and sclerotial production even at 0.025% (Karmaiyan and

Prasad, 1979). Dev (1980) applied soil fungicides thiram and quintozene before planting (@ 20

kg/ha) to kill soil-borne sclerotia. A single application of edifenphos (0.5 1) may be made at maximum

tillering stage or benomyl, carboxin or carbendazim at 0.5 kg/ha may be sprayed three times at 14

days intervals. Thiram and endifenphos were most effective followed by quintozene, edifenphos for

soil application. Benomyl killed sclerotia when dipped for 48 hr. but spraying or soil application of

benmyl and polyoxin could not kill the sclerotia on rice plants or the soil surface in Taiwan (Leu and

Young, 1979). This completely contradictory result suggests that chemotherapy control may very

between localities or that development of resistant strains of the fungus or adverse effects of soil and

environmental on the chemical may be related.

In many situations, chemical, control is unlikely to be economically worth while, especially in the

tropics where yields are low, but it may be related., tropics where yields are low, but it may be justifiable

in very heavy attacks or on seedlings otherwise control must largely depends on planting varieties which

are not too susceptible and the adoption of suitable culture practices (Gangopadhyay and chakraborti,

1982). Roy (1993) advocated that since commercial variety resistant to sheath blight is not available, the

strategy of management will be to destroy weeds and undertake need based spraying operation for

which a number of effective chemicals are available. Use of herbicides may be considered for destruction

of weeds. If feasible, stubble may be burnt after harvest.

REFERENCES

1. Baby, V.I. and K. Manibhushan Rao, 1993. Control of rice sheath blight of through the integration of fungal antagonists and organic amendments. Tropical Agric. 70-: 240-244.

2. Dev, V.P.S. 1980. Sheath blight control with soil fungicides. IntI. Rice Res. Newsletter. 5: 14-15.

3. Ganamanickam, S. S. ; Candloe, B. L. and Mew, T. W.. 1989. Influence of soil factors and culture practice on biological control of sheath blight of rice with antagonistic bacteria. Progress report, Deptt. of Plant Pathology, IRRI, Philippines.

4. Ganamanickam, S. S. and Mew, T. W. 1990. Biological control of rice disease (blast and sheath blight) with bacterial antagonistic. An alternate strategy for disease management. In: Pest management in rice, edited B. T. Grayson, M. B. Green and L. G. Copping Elsevier Applied Science Pub. Ltd 87-110.

5. Gangopadhyay, S. and N. R Chakraborti. 1982. Sheath blight of rice. Rev. Plant Path. 61: 451-460

6. Gogoi, R and Roy, A. K. 1993. Effect of foliar spray of Aspergillus terrus thorn on sheath blight (shh) and rice plant characteristics. Indian Phytopath. 49: 32-35

7. Gokupalan, C. and Nair, M. C. 1984. Antagonistic of few fungi and bacteria agent Rhizoctania solani Kuh. Indian J Microbial. 24: 57-58

8. Kanniyan, S. and Prasad, N. N. 1979. Control of sheath blight of rice. Ibid 4: 15

9. Kanniyan, S. and Prasad, N. N. 1979. Effect of fungicides on the inaction of Sclerotia and mycelia


- 156 -

of Rhizoctonia solani. Ibid. 4: 13.

10. Khan, A. A. and A.P. Sinha (2005). Influence of soil and nutritional factors on the effectivity of Trichoderma harzianum against sheath blight of rice. Indian Phytopath. 58:276-281.

11. Khan, A. A. and A.P. Sinha (2007). Factors effecting of Trichoderma spp. as biocontrol agents against sheath blight of rice. Indian Phytopath. (Accepted).

12. Khan, M.W.,Khan, A..M. and Saxena S.K. (1973) Influence of certain oil cakes amendments on nematodes and fungi in tomato fields .Acta Bot. Indica. 1: 49-54.

13. Kurucheve,V, Ezhilan, J.G. and Jayraj, J. (1997). Screening of higher plants for fungitoxicity against Rhizoctonia solani in vitro. Indian Phytopath., 50: 235-341.

14. Lee, H. R; Xiao, J. G. and Yan, S. Q. 1993. Acta Phytopath. Sinica, 23: 101-105.

15. Lee, Y. H.; Shim, G. Y.; Lee, E. J. and Mew, T. W. 1990. Evaluation of biological activity of fluorescent pseudo monads against some rice fungal diseases in vitro and glasshouse. Korean J Plant Paihology. 6: 73-8

16. Leu, L. S. and Yang, H. C. 1979. Comparative study on the effectiveness of the eight recommended fungicides to control rice sheath blight. Plant Proto Bull. Taiwan, 21: 323-329.

17. Mamian, S. and Paulsamy, S. 1987. Biological control of sheath blight disease of rice. J Bio. Control. 1: 57-59.

18. Mew, T. W. and Rosales, A M. 1986. Bacterization of rice plants for control of sheath blight caused by Rhizoctonia solani. Phytopathology. 76: 1260-1264.

19. Papavizas, G. C. and Lewu, J. A 1979. Integrated control of Rhizoctonia solani In: Soil borne plant pathogens (Edited Scippers, B: and W. Gams) Academic Press, London, 415-424.

20. Rajan, K. M. 1980. Soil amendments in plant disease control. Inti. Rice Research Newsletter 5:15.

21. Roy, A.K. 1993. Sheath blight in India. Indian Phytopath. 46 ; 197-205

22. Roy, AK. 1978. Percent of rice plants infected by sheath blight in different treatment of spacing and nitrogen application. Curro Sci. 47: 307-308.

23. Roy, AK. 1985. Antagonistic effected bhaincha on survival of Rhizoctonia solani f.sp. sasakii. Intn. Rice Res. Newsletter. 10: 9-10.

24. Shivpuri, A.; Sharma, O.P. and Jhamaria, S.L. (1997). Fungitoxic properties of plant extract against pathogenic fungi, J. Myco. Plant Path., 27: 29-31.

25. Singh RajVir and A.P.Sinha (2005) Influence of application methods of Pseudomonas fluorescens on rice sheath blight Indian Phytopath. 58:474-476.

26. Singh, RajVir, and A.P.Sinha (2004) Comparative efficacy of local bioagents, commercial bio-formulations and fungicide for the management of sheath blight of rice, under glass house condition. Indian Phytopath, 57:494-496.

27. Singh, S.K., V.Shukla, H.P.Singh and A.P.Sinha (2003) Current status and impact of sheath blight in rice (Oryzae sativa L). Agril. Reviews 25:289-297.

28. Vaish, D.K. and A.P. Sinha (2003). Determination of tolerance in Rhizoctonia solani, Trichoderma virens and Trichoderma sp. (Isolate 20) to systemic fungicides. Indian J. Pl. Pathol., 21:48-50.

29. Vaish, D.K. and A.P. Sinha (2004). Characterization of isolates of Trichoderma spp. for their biocontrol ability against Rhizoctonia solani. Indian J. Pl. Pathol. 22:123-127.

30. Vaish, D.K. and A.P. Sinha (2006). Evaluation of fungal antagonists against Rhizoctonia solani causing sheath blight of rice. Indian J. Agril. Res.40:79-85.

31. Verma, AS.; Peethambaram, C.K.; Balakrishnan, S. and Menon, RR 1978. In vitro effect of certain herbicides formulations on Corticium Sasaki (Shrai). Matysumoto. Agril. Res. J. Kerla. 16: 114-116.


- 157 -

Integrated Management of Maize Diseases with Special Reference to Banded Leaf and Sheath Blight

S.C. Saxena

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand) Maize ( Zea mays L. ) is the third most important cereal crop in the world agricultural

economy as food for man and feed for livestock. The total area under maize cultivation in the

world is about 127.38 m.ha with a total production of 470.5 m tonnes with the average yield of

3694 kg/ha.

About 112 diseases of maize have been reported so far from different parts of the world, of

these 65 are known to occur in India. The major diseases in different agro-climatic regions are,

seed rots and seedling blight, leaf spots and blights, downy mildews, stalk rots, banded leaf &

sheath blight, smuts & rots leading to about 15-20 percent yield loss annually.

Pantnagar is one of the hot spot for number of disease but identified for Banded leaf and

sheath blight, Brown stripe downy mildew and Erwinia stalk rot. The studies are being carried out

at this location for last 35 years on epidemiology, pathogen variability and disease management

using chemicals, cultural practices, bio-control agents including evaluation of maize genotype for

resistance sources.

There are five downy mildews present in the country in different state viz., brown stripe

downy mildew, sugarcane downy mildew, sorghum downy mildew, rajasthan downy mildew and

Philippine downy mildew. The work carried out under AICRP and IACP programme over the years

obtained resistance to above downy mildews and incorporated in improved varieties during

resistance breeding programme. Similarly there are six stalk rots prevalent in different states

causing severe losses at and after flowering of the maize plant. These stalk rots are Pythium stalk

rot, Bacterial stalk rot, Acremonium stalk rot, Maydis stalk rot, Fusarium stalk rot and charcoal

stalk rot. Success has been made in managing these stalk rots following cultural practices

effectively. However, bacterial stalk rot can be minimized by application starting at the onset

flowering bleaching powder @ 25kg per ha. and second application after 10 days.

Banded leaf and sheath blight (BLSB) is the most important one. This diseases is known

under many names and is caused by Rhizoctonia solanni = Hypochonus sasakii (Thanatephorus

cucumeris (frank) Donk). It is one of the most widespread, destructive and versatile pathogen. It

is found in most parts of the world and is capable of attacking a wide range of host plants including

maize causing seed decay, damping-off, stem canker, root rot, aerial blight and seed/ cob decay.

It is due to combination of its competitive saprophytic ability and high pathogenic potential that

makes H. sasakii a persistent and destructive plant pathogen.

The symptoms of the Banded leaf & sheath blight are observed on all aerial parts of the

maize plant except tassel. The disease manifests itself on leaf, leaf sheaths, stalks and ears as

leaf & sheath blight, stalk lesions or rind spotting and stalk breakage, clumping and cracking of


- 158 -

styles (silk fibre), horse-shoe shaped lesions with banding of caryopses, ear rots, etc. Under

natural conditions, disease appears at pre- flowering stage on 30 to 40 day-old plants but infection

can also occur on young plants which may subsequently result in severe blighting and death of

apical region of growing plants.

Under natural conditions, dropping blades especially the distal halves of leaves proximate

to soil surface are affected. Infection spreads from leaf shealths to the basal portion of leaves.

Lesions appear as in irregular patches, similar in colour but larger in size and spread more rapidly

than on leaf sheath, covering greater areas with alternating dark bands. The symptoms are more

common on sheaths than on leaves. The disease appears on basal leaf sheaths as water soaked,

straw colored, irregular to roundish spots on both the surfaces. A short of wave pattern of disease

advancement can be seen not only on leaves but also on sheaths and husk leaves. In early

stages marginal chlorosis and rotting of laminae proceed inwardly. Later as the infection becomes

older numerous sclerotial bodies are also seen.

The pathogen also causes elongated dark brown to black spots of lesions on the rind of the

stalk under the affected sheaths. These spots coalesce together extending the lesions and

covering almost an internode. Individual lesion range in size from 2-10 x 3-15 mm to those which

cover the whole internodes. Some times these lesions are transformed into cankers and a few

girdle near the nodes. Under artificial inoculation entire rind is some times affected, the stalk

thereby weakened and breaks easily. The disease observed first of all, on basal part of the

outermost husk leaves forwarding to sheath from which the ear emerge. The same types of

lesions are found on ear but the bands are fairly prominent, giving a blackened appearance. The

affected ears become brown and numerous sclerotia are observed on husks, lightly attached to

the cob. Whitish mycelium and sclerotia are also seen frequently on silks between and on kernel

rows and glumes.

The grain showed light greyish to dark brown discoloration, drastically reduced in size and

wrinkled, and under severe conditions, the grain became chuffy and light in weight.

Diseases Management

Chemical Control

The experiment was planned using 18 fungicides in three replications following randomized

block design. The plot size was kept 5 x 3 m2 with 4 rows at 75 cm apart. All the plants were

artificially inoculated at 40th and 50th day of planting followed by foliar sprays of fungicides after 3

days of inoculation. The observation on disease severity, 1000-grain weight, grain yield per ha

and cobs/plant were recorded and analyzed statistically. Only thiobendazole was found most

effective followed by Duter & Vitavax in reducing the disease severity and resulting in higher grain

yield while in following year only 10 fungicides were included based on the performance in

previous year testing. Of these vitavax (carboxin), TPTH (Triphenyl tin hydroxide) and

thiobendazole were found to be most effective.


- 159 -

During last few years, some newer chemicals which are claimed to be effective against

sheath blight disease were also tested under different sets of experiments. The chemicals viz.,

Propaconazole, 0.1% (Tilt) & carbendazin, 0.05% (Savistin or Bavistin) were tried following

different methodology.Both the chemicals were applied as foliar sprays at 30, 40 and 50th day of

planting alone or in combinations of application. The experiments were planted in three

replications following Randomized Block Design. The plot size was 7.5 m2 with 2 rows of 75 cm

apart. Artificial inoculations were carried out after 40th day of planting and repeated after 2 days of

first one. The chemicals were applied as per treatment and the data on disease severity and yield

parameters were recorded and analyzed statistically. The result indicated that the effectiveness of

Propaconazole was markedly observed when the chemical was applied at initial stages at 30th or

40th day of planting and the second spray at 10 days after first. Foliar sprays of Carbendazim

showed the ineffectiveness against BLSB as well as on the yield parameters.

Visualizing the efforts on chemical control which were not so effective from practical

application point of view, the other approaches for disease management were also included in the

studies.

Biological Control

Bio-control agents Trichoderma harzianum, Gliocladium virens, Pseudomonas sp. were tried

alone or in combination with propaconazole and carbendazim along with a cultural control treatment

with common check. All the methodology was the same as discussed in previous experiments.

None of the treatment effectively reduced the disease but foliar sprays of T. harzianum +

Tilt followed by T. harzianum sprays, Saivistin + Tilt + T. harzianum, Savistin + Tilt and Savistin

alone could exhibit some reduction in disease levels. Cultural practice, removal of lower leaves

alone was not be so effective and would not be practicable to the farmers. While evaluating the

biocontrol bacteria against R. solani, the fluorescent Pseudomonas could not reduce the BLSB.

Subsequently in nature, it had been observed that the pathogen H. sasakii, when infects

cob shank and husk, the T. harzianum also parasitizes the fungus. The mycoparasitism by

Trichodioma leads to a synergistic action in increasing the cob rot and grain infection. To find out

the synergistic action of both the fungi, an experiment was planned following randomized block

design and three replication in field under artificial inoculation of the organism alone or in

combinations which indicated that the present of R. solani followed by the infection of Trichoderma

was more harmful that is what happening in nature also.

Disease Resistance

Different genotypes received from various sources were evaluated under All India

Coordinated Research Project on Maize at Pantnagar using artificial inoculation techniques.

Following genotypes are grouped as resistant/moderately resistant.

CM-103, CM-104, CM-105, CM-211,CM-117,CM-118-1, CM-118-2, CM-200,CM-201, CM-

202, CM-205, CM-300, CM-500, CM-600, Eto 182, Aust 25, P217, P 407, CML- 267, Antigua

Gr.II, JML-32, JML-306, JML-403, VL-43, CM 107 x CM 108, RN6Ht1 A x GE 440.


- 160 -

Role and limitations of Botanicals in the Management of Plant Diseases

A.P. Sinha and G.P. Gangwar Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

During the last few years, the agricultural strategy has acquired a new dimension. The use

of high yielding varieties and hybrids has become a significant aspect of new technology which is

being accompanied by a series of related changes in agricultural practices such as massive

application of fertilizers and plentiful irrigation. This has given rice to a drastic change in

complexion of plant diseases. Major diseases have developed from miner one which are

previously of little or no importance.

A variety of chemicals including fungicides, antibiotics, bacterial and homeopathic drugs

have been evaluated for their efficacy both as protectant and therapeutant against various

diseases. Currently, pesticides registrations are lost due to concern about their safety and

environmental impacts. Further, pesticides are of high energy inputs and are also costly. Toxins

from diseases including micro-organisms are major factors in the development of a number of

destructive plant diseases. Three classic cases often cited are the huge losses in oat production in

North America from 1946-to 1948, rice production in India (Bengal famine) during 1942-43 and

maize production in South America during 1970-71, caused by the fungus, Helminthosporium sp.

In all cases toxins were the major factors in the destructive processes and epidemic.

Plant products are gaining importance in crop protection in view of selective properties, low

cost and safety to ecosystem. Many plant products have been identified to be effective in the

control of plant diseases. The botanical pesticides such as neem would be a potential method of

disease control and increase the crop productivity. The neem product inhibits mycelial growth

reduced leaf spots, rusts, mildews, rot diseases and moulds. Additives are able to prolong the

persistence of the neem products on the vegetation. Neem products have inhibited germination

and growth of pathogens. Lesions formed by the pathogens on plants were observed restricted by

pre-inoculation spray of neem extracts (Mariappan, 1998). During the past three decades

innumerable numbers of publications have appeared through various forums and most of them

were on its efficacy in the control of insect- pests. Relatively less number only appeared on its

efficacy on the pathogenic populations (fungal, bacterial, viruses and nematodes) of crop plants.

The information available from their research efforts of earlier decades were mostly from the

exploratory investigations. The usefulness of neem and other plant products for the management

of crop diseases of food crops and commercial crops have been demonstrated by many scientists

all over the country and are available in recent years. In this article, an attempt has been made to

compile some of these information’s on the evidences of management of crop diseases by using

plant products.

Effect of botanicals on fungal diseases

In vitro


- 161 -

Shivpuri et al (1997) tested fungicidal properties of 10 plant species extract against

pathogenic fungi. Ethanol extracts of 10 plant species (Allium cepa, A. sativum, Azadirachta

indica, calotropis procera, Datura stramonium, Ocimum sanctum, polyalthia longifolia, Tagetes

erecta, Vinca rosea, and Withanea somnifera were assessed against 5 pathogenic fungi. (Alteraria

brassicola, Colletotrichum capsici, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia

sclerotioru.m, and tested under laboratory conditions at two concentrations (500 and 1000 micro g/

ml). The leaf extracts of A.. indica, O. stramonium O. sanctum, P. longifolia and V. rosea were

found more fungitoxic than other extracts. This efficacy was more pronounced at 1000 micro g /ml

as evidenced from the low redial growth.

Narasimhan et al (1998) evaluated neem oil (NO) and pungam oil (PO) based emulsifiable

concentrate (EC) formulations, Viz, NO 60 EC (acetic acid), NO 60 EC (citric acid) and NO+PO 60

EC (citric acid) which had been developed and evaluated for their efficacy against sheath rot

(Sarocladium oryzae) of rice. All 3 formulations effectively inhibited the mycelial growth of the

causal pathogen under in vitro conditions. There was no significant difference between efficacy of

the freshly prepared and stored formulations in arresting the growth of S. oryzae, efficacy was

maintained even after 9 month of storage. These formulations effectively controlled rice sheath rot

and led to increased yield. Enikuomehin et al (1998) screened ash samples, from organs of 9

tropical plants for their abilities of inhibiting mycelial growth and sclerotial germination of a

Nigerian isolate of Corticium rolfsii on agar and in the soil. Of the 11samples tested, 10 showed

some activity against mycelial growth of C. rolfsii in vitro. Ash samples from 9 sources protected

seeds against pre-emergence rot. Ash from M.indica leaf, V. amygdalina leaf and Azadirachta leaf,

protected seedling against post-emergence infection.

Neem products viz. Neem gold, Neemta, Replin, Achok and Nimbicidine were evaluated

against mycelial growth of P. drechsleri f.sp. cajani, the causal organism of Phytophthora blight of

pigeon pea (Chauhan and Singh, 1998). Of these, Achook was most effective and completely

checked the radial growth of the fungus in 14 and 21 days at 24 and 48 micro g/ ml concentration,

respectively. Reptlin was also effective at 48 micro g/ ml and inhibited the growth of mycelium, till

24 days. The effect of Achook at 24 micron g/ml was fungistatic. However, the concentration of 48

micron g/ ml of Achook and Reptlin were fungicidal.

Soil application

Hooda and Srivastava (1998) sudied the impact of neem coated urea (NCU) and potash on

the incidence of rice blast ( Magnaporthe grisea). All 3 levels of NCU used (30, 60, 90 kg N/ha

were effective in reducing the disease. However, neck and node blast incidence, NCU at 30 kg

N/ha had no effect as compared with control. NCU at 60 and 90 kg N/ha significantly reduced the

disease as compared with the control. The highest cost benefit ratio was recorded for NCU at 60

kg N/ha, followed by 90 kg N/ha. The 3 rates of potash used (15, 30 and 45 K2o/ha) had no effect

on the incidence of rice blast or yields.

It has been observed that of the organic amendments tested in pot experiments, neem.


- 162 -

cotton, ground nut and safflower cakes reduced the inoculum levels of Macrophomina pheseolina

and Fusarium moniliforme (Gibberella fujikuroi) in the soil, and reduced the incidence of stalk rot

of sorghum. Except for with neem cake, the populations of beneficial bacteria, fungi and

actinomycetes were higher in amended soil than in non-amended soils (Hundekar et al., 1998).

Ehteshamal Haque et al. (1998) observed soil amendment with neem seed cake, cotton seed

cake, Datura fastuosa and steocho-speimum marginatum significantly reduced Fusarium solani

infection of sunflowers in Pakistan. Neem seed cake and cotton seed cake were also effective

against Macrophomina phaseolina and Rhizoctoria solani, while S. marginatum and D. fastuosa

were effective against R. solani infection of sunflower roots. P.aeruginosa significantly controlled

root diseases of sunflower caused by M. phaseolina, R.solani and F. solani. P.aeruginosa

combined with neen seed cake or S. marginatum produced greater fresh weight of shoots and

plant height, respectively, compared with separate applications.

Prasad et al (1998) studied survival of sclerotia of R. solani in rice soils amended with oil

cakes and green leaf manures. The effect of oil cakes (neem cake, ground nut cake, sesame

cake) and green leaf manure viz Calotropis sp; Crotolaria sp. and Phaseolus sp. on sclerotial

survival of R. solani ( causing rice sheath blight) was studied in 3 rice land soils. Neem cake and

Calotropis were the most effective in affecting the survival of sclerotia in the soil.

Foliar application

Naik and Shrivana (1997) carried out a study on the control of mildew caused by Oidium

sp. on polybag seedling of Accacia auriculiformis in the nursery in Karnataka, during Kharif 1996.

Treatments tested were: Calixin (tridemorph) and Bavistin (carbendazim),both at 0.1 percent

wettable sulfur at 0.3 percent, and Nimbicidin and Clerodendron leaf extract, both at 0.5

percent. Callixin was most effective treatment, reducing disease incidence by 57.0 percent

followed by Bavistin (40.1%) and Nimbicidin (39.4%). The Clerodendron leaf extract was least

effective (18.6%). Pramanick and phookan (1998) tested effect of 10 plant extracts in the

management of sheath rot (Sarocladium oryzae) of rice. An aqueous extract of Ocimum sanctum

was the most effective followed by Euaclptus citriodora and Azadiracta indica. Lesions formed by

the pathogen on rice plants (cv. IR 36) were also significantly restricted by pre-inoculation spray

with these three plant extracts. Lokhande et al. (1998) tested effect of different fungicides and

neem products for the control of leaf spot of ground nut. The results of field trials conducted on

ground nut variety TAG-24 revealed that a combined spray to carbendazim + tridemorph was

significantly superior to the other fungicide treatments viz, mancozeb, carbendazim and tridemorph

alone in respect of lowest percentage disease incidence of leaf spot (19.48%), caused by

Mycosphaeralla arachidis and highest pod yield (20g/ha). The neem products (neem seed extract

and neem oil) were less effective than the fungicides but the treatments were significantly superior

in comparison with the control.

Post harvest diseases

Ali et al (1992) reported the effect of neem products as mould inhibitors against post


- 163 -

harvest fruit rotting fungi on tomato in vitro. Neem oil, leaf extract and pericarp dust (from A.

Indica), together with Tecto-60 (thiabendazole) and boric acid, were tested against isolates of

Penicillium italicum, Alternaria alternata and Aspergillus niger from rotted fruit, Only neem oil was

effective as thiabendazole in checking growth of these fungi. Moline and Locke (1993) reported the

effect of neem seed oil and other fungicides for controlling post harvest apple decay. The

antifungal properties of a hydrophobic seed extract from A. indica were tested against the post

harvest apple pathogens; Botrytis cinerea, Penicillum expansum and Glomerella cingulata. The

antifungal activity of neem seed oil was also compared with that of calcium chloride. A 2%

aqueous emulsion of the clarified neem seed oil was moderately fungicidal to B. cinerea and G.

cingulata in inoculated fruit, but had little activity against P. expansum. Ethylene Production was

reduced by 80 percent in fruit dipped in 2 percent neem seed oil compared with wounded,

inoculated controls. Neem seed oil was as effective as calcium chloride but the effect of the 2

antifungal agents in combination were not additive. Fajardo et al (1998) conducted a study to

evaluate the efficacy of selected inducing agents in reducing the incidence and severity of green

mould caused by Penicillium digitatum in mature oranges (cv. Valencia). The inducing agents

tested were margosan (a neem product). Aspire (biological post harvest diseases controlling

agent) consisting of a water dispersible granule containing an antagonistic yeast Candida

oleophila and chitosan (prepared from crab shells). There agents and Chitosan + Aspire reduced

fruit decay by 38, 41, 42, and 44 percent, respectively. Singh and Korpraditskul (1999) compared

the efficacy of neem, garlic and tagak-togak (Rhinocan thusnasuta) at 5000 ppm on green chilly

with the fungicide carbendazim at 100 ppm. Green chilly fruits in 100 numbers were cleaned and

sterilized and were dipped in Colletotrichum capsici spore suspension for 2 min and air dried.

Treated fruits were inoculated over night. The chilly fruit were dipped for a 5 second in each plant

extract and carbendazim.. The results indicated that crude plant extract of neem, garlic ant tagak-

tagak showed a singnificant effect (P< 0.01) in the expression of spots on chilly when compared to

control. The garlic extract was best. Neem extract minimized that ripe chilly rot.

Pandey et al (1983) reported the control of Pestalotia fruit rot of guava dry leaf extracts of two

medicinal plants. Leaf extracts of A. Indica and Ocimum sanctum inhibited germination of P. psidii

spores in vitro and on guava fruits dipped in these extracts before or after inoculation. O. sanctum

extracts were recommended as they do not affect fruit flavour.

Effect of botanicals on bacterial diseases

Pierce (1981) observed that neem product AZ at 0.25 percent controls bacterial wilt caused

by Pseudomonas solanacearum. Maharishi (1993) observed encouraging results in controlling

bacterial leaf spot of chilli caused by Xanthomonas campestris pv vesicatona with 2 percent of

aqueous leaf extract of neem. Eswaramurthy et al. (1993) found that to control bacterial blight of

rice, X. campestris pv oryzae, 2 percent spray of NSKE is effective. Hulloli et al. (1998) studied

the management of bacterial blight of cotton induced by X. axonopodis pv malvacearum with the

use of neem-based formulation. The MIC of the neem-based formulation plantolyte and agricare


- 164 -

against X. axonopodis pv malvacearum was 1 ug/ml. This was lower than the MIC of

aminoglycosides, streptomycin and kanamycin (2.5µ/ml.).

Effect of botanicals on viral diseases

Tripathi and Tripathi (1982) observed that crude leaf extract of Azadirachta indica was to

be most potent in reducing bean common mosaic virus infectivity. Mariappan et al. (1982) studied

the effect of custard apple oil and neem oil on the life span and rice tungro transmission. Studies in

the Philippines sowed that the treatment of rice seedlings with oil extracted from the seeds of

A.indica and Annona sp. significantly shortened the life-span of Nephotettix virescens (Dist.)

carrying rice tungro virus when confined on the plants and significantly reduced the incidence of

transmission of the virus. Saxena et al. (1987) observed the reduction of tungro virus transmission

by N. virescens in neem cake treated rice seedlings. Nagarajan et al. (1990) utilized leaf extracts

of many plants against tobacco mosaic virus (TMV). A large number of botanicals possess antiviral

substance which when sprayed on tobacco early in the season gave good protection against TMV

infection. Somasekhara et al. (1998) evaluated neem products and insecticides against whitefly

(Bemisia tabaci), a vector of tomato leaf curl, Gemini virus disease. High mortality of B. tabaci was

observed with neem products NSKE (100) and RD 9 Repelin at 4 and 1 percent, respectively but

the efficacy persisted for 48 hrs only.

Botanicals have wide scope for commercial exploitation for the management of crop

diseases. Further studies on the identification and characterization of the fungitoxic principles will

be useful in developing commercial biofungicides. Due to problems and phytotoxicity, the spray

concentration of the various plant products needs to be standardized.

REFEENCES

1. Ali, T.E.S.; Nair, M. A. and Shakir, A.S.(1992) in vitro evaluation of certain neem products as mould inhibitors against post harvest fruit rotting fungi of tomato. Pakistan J.Phytopath. 4 (1-2):58-61.

2. Chauhan, V.B and Singh.V.B (1998). In vitro effect of some neem products on mycelial growth of Phytophthora drechsleri F.sp. cajani. Abs. pp MSA 11- 13 Dec., 1998 at CSAU A and T Kanpur: 148

3. Ehteshamul Hague; Zaki; M.J.; Vahidy, A.A. and Abaul Graffas (1998) Effect of organic amendments on the efficacy of Pseudomonas aeruginosa in the control of root rot diseases of sunflower. Pakistan J. Botany, 30 (1):45-50

4. Enikuomehin, O.A.; Ikotun, T. and Ekpo, E.J.A.(1998). Evaluation of ash from some tropical plants of Nigeria for the control of Sclerotium rolfsii sacc. on wheat (Triticum aestivum L.) Mycopathologia,142(2):81-87

5. Fajardo, T.E.; Mc cellum, T.G.; Mc Dehald, R.E. and Mayer, R.T. (1998). Deferential induction of proteins in orange flavedo by biologically based elicitors and challenged by Penicellium digitatum Sacc. Biological control. 13(3): 143-151.

6. Hooda, K.S. and Srivastava, M.S. (1998). Impact of neem coated urea and potash on the incidence of rice blast. Plant Dis. Research,13 (1):

7. Hundekar, A.R.; Anahosur, K.H.; Patil, M.S.; Kalapannavar. I.K.. and Chattannavar, S.N. (1998) In vitro evaluation of organic amendments against stalk rot of sorghum. J. Mycol. and Plant Path. 28 (1):26-30.


- 165 -

8. Lokhande, N. M.; Lanjewar, R. D. and Newaskar. V.B. (1998). Effect of different fungicides and neem products for control of leaf spot of groundnut. J. Soils and Crops.8 (1) : 44-49

9. Maharishi, R.P. (1993). Management of chilli (Capsicumnm annuum L.) diseases by neem based preparations. World neem conference, Bangalore, India : 34

10. Mariappan, V. (1998). Neem for the management of crop diseases. Associated Publishing Ccompany, New Delhi. Pp.220.

11. Moline, H. E. and Locke, J.C. (1993). Comparing neem seed oil with calcium chloride and fungicides for controlling post harvest apple decay. Hort. Science, 28 (7): 719-720.

12. Nagarajan et al (1990), Effect of plant extracts and oils on rice Yellow dwarf infection. Madras Agric. J., 77: 197-201.

13. Naik, S.T. and Shivanna, H. (1997). Management of powdery mildew of Acacia auricliformis. Indian Forester, 123 (9): 868-869.

14. Narasimhan, V.; Rajappan, K.; Ushamalini, C. and Kareem, A.A.(1998). Efficacy of new EC formulations of neem oil and pungam oil for the management of sheath rot disease of rice. Phytoparasitica, 26 (4): 301-306

15. Pandey, R.S.; Bhargava, S.N.; Shukla, D.N. and Dwivedi, D.K. (1983). Control of Pestalotia fruit rot of guava by leaf extracts of two medicinal plants Revista Mexicana de Fitopatologia, 2 (1) : 15-16

16. Pierce, R. (1981). Natural products repel cucumber bettle. Agricultural research (USA), 30 (2) :12

17. Pramanick, T.C. and Phookan, A.K. (1998). Effect of plant extracts in the management of sheath rot of rice. J. Agric. Sci. Soc. North East India. 11 (1): 85-87.

18. Prasad, M.S.; Lakshmi, B.S. and Shaik Mohiddin (1998). Survival of sclerotia of Rhizoctonia solani in rice soils amended with oil cakes and green leaf manures. Ann. Agric. Res. 19 (1):44-48.

19. Saxena, R.C.; Khan, Z.R. and Bajet, N.B. (1987). Reduction of tungro virus transmission by Nephotettix virescens in neem cake treated rice seedlings. J. Econ. Entomol.. 80 (5) : 1079-1082

20. Shivpuri, A.; Sharma, O.P. and Jhamaria, S.L. (1997). Fungitoxic properties of plant extracts against pathogenic fungi, J. Myco.Plant Path.. 27 (1): 29-31.

21. Singh, H. and Vichai Korpraditskul (1999). Evaluation of some plant extracts for the control of Colletotrichum capsici (Syd). Butler and Bisby, the causal agent of chilly anthracnose. Azadirachta indica A. Juss. Ed. Singh and Saxena: 131-138.

22. Somasekhara, Y.M.; Natishan, B.M and Muniyappa, V. (1998) Evaluation of neem products and insecticides against westifly (Bemesia tabaci) a vector of tomato leaf curl Geminivirus diseases. Neem Newsletter, 15 (2) : 16.

23. Tripathi, R.K.R. and Tripathi, R.N. (1982). Reduction in bean common mosaic virus (BCMV) infectivity vis-à-vis crude leaf extracts of some higher plants. Experimentia, 38 (3): 349.


- 166 -

Arbuscular Mycorrhiza: A Potential Bioagent for Managing Plant Disease

Rashmi Srivastava and A. K. Sharma Department of Biological Sciences, CBSH, G.B.P.U.A.&T., Pantnagar-263145 (Uttarakhand)

The obligately biotrophic relationship of the arbuscular mycorrhizal (AM) fungus in the root

cortex and the regulation of colonization by carbon supply are strongly suggestive that

mycorrhizas interact directly with root pathogens that have similar trophic requirements.

Aphanomyces euteiches is a biotrophic pathogen that attacks root cortical tissues of pea and other

legumes. The potential exists for resource competition between the symbiotic fungus and

pathogen, leading to the reduction of each other’s colonization and reproduction when they

coinhabit roots. Larsen & Bodker (2001) use fungal specific neutral lipid fatty acids as indicators of

infection and energy status of Glomus mosseae and A. euteiches in pea roots to measure the

interaction of these trophically similar fungi. The presence of G. mosseae does not affect root rot

severity of A.euteiches but reduces the level of energy reserves and sporulation of the pathogen in

the root cortex. Concomitantly, the biomass and energy reserves of the AM fungus are reduced as

well. In many studies, mycorrhizal mediated effects on host nutrition indirectly influence the

outcome of these interactions because they have been often studied in phosphorus-deficient soils.

Larsen & Bodker’s (2001) study is one of the first attempts to resolve the direct trophic interactions

based on competition for C and possibly other nutrients between the symbiont and other

organisms colonizing the root cortex and mycorrhizosphere.

In 1981, Schenck commented that the answer as to whether or not mycorrhizas can control

root diseases would “require a crystal ball” ’

Can mycorrhizas control root diseases?

Modern study of arbuscular mycorrhizas began with plant pathologists, who viewed roots

primarily as hosts for parasitic and pathogenic fungi and nematodes. Their research was among

the first to define the normative state of the root cortex as the colonization site for arbuscular

mycorrhizal fungi (AMF), as well as soilborne fungi, bacteria and nematodes. Gerdemann (1975)

conducted pioneering studies in the 1960s to demonstrate the functional role of external hyphae of

these fungi in the acquisition of plant nutrients, especially in low P availability soils. Plant growth

response to inoculation at low nutrient supply soon stimulated interest in AM fungi as biocontrol

and stress-reducing agents, especially after initial studies showed heightened resistance of roots

to infection by fungal pathogens, such as Thielaviopsis basicola , and the root knot nematode,

Meloidogyne incognita (Schoenbeck, 1979). In sharp contrast to the positive benefits in these

pathosystems, susceptibility to some pathogens (e.g. Phytophthora spp.) was increased for certain

hosts (Ross, 1972).

Only limited evidence has emerged that the AM fungi compete directly with other biotrophic

organisms for the same cortical space and resources. Other mechanisms invoked are as diverse

as the results of the interactions, but are often cited as structural and biochemical resistances


- 167 -

induced by the AM fungus in the root cortex, or as attributable to alterations in the

mycorrhizosphere microflora (Lindermann, 1994). In a definitive review of the early literature on

‘VA mycorrhizas’, Gerdemann (1975) issued a caveat: ‘in studies of the effect of VA mycorrhizas

on disease it should be determined whether changes in resistance are caused by increased

nutrient absorption or if the effect is more direct’. Schenck (1981) conducted research on

mycorrhizal interactions with a diversity of root-infecting fungi and nematodes. But by 1981,

Schenck remarked in apparent frustration: ‘the answer to “can mycorrhizas control root diseases”

would require a crystal ball or a soothsayer!’

Rhodes (1980) wrote in a prescient review of the benefits of AM fungi in agricultural

systems that ‘root pathogens should in most instances be regarded as pathogens of mycorrhizae,

since it is the mycorrhizal root that is encountered by pathogens in most cases. Pathogenic

microorganisms have coevolved with arbuscular fungi and have been exposed to the mycorrhizal

condition of roots over thousands of centuries. The very fact that root diseases still occur indicates

that such pathogens have successfully adapted to parasitize mycorrhizal hosts. Nevertheless, any

role that mycorrhizal fungi may play in restricting or enhancing disease development is deserving

of attention.’

Defining mechanisms unrelated to improved phosphorus nutrition

Molecular probes provide unprecedented opportunity for comparative study of expression

of plant resistance in AM fungal vs pathogen interactions. Thus far, the evidence that arbuscular

mycorrhizal colonization conditions systemic resistance to other pathogens, such as through up-

regulation of pathogenesis-related proteins, remains controversial (Blee & Anderson, 2000).

Apparently, the expression of genes encoding plant defenses is weak when AM fungi colonize

roots and, at later stages, colonization even suppresses plant defense-related genes. Given the

low specificity of AM fungi, it is not unreasonable to expect suppression of general host defenses.

Systemic priming of root tissues to form structural and biochemical barriers is usually dependent

on a high level of root colonization and cannot always be verified as mycorrhiza specific because

the P status of the plant before pathogen challenge is unknown (Cordier et al. , 1998).

Smith (1988) provided the first well defined framework for predicting interactions in the

host–mycorrhiza–pathogen triangle based on trophic relationships. He proposed that the potential

for AM fungi to affect host–pathogen relationships by mechanisms unrelated to improved P

nutrition is greatest for obligate biotrophs (e.g. endoparasitic nematodes) and least for facultative

saprotrophic fungi (e.g. certain species of Fusarium, Phytophthora and Rhizoctonia). In most

instances, direct mycorrhizal effects are most clearly evident for measurements of parasitic

nematode development. He judged that AM fungi are probably affecting host–pathogen relations

by physiologically altering the host or competing for space or host resources. Smith noted that

experimental data are scant for host resource competition between pathogens and AM fungi and

encouraged investigations of C as well as P flow between root-inhabiting organisms that have

obligate requirements for host-derived C.


- 168 -

Resource availability in the root cortex vs the mycorrhizosphere

More evidence is emerging that intraradical hyphae of AM fungi efficiently take up sugars

from the root apoplast and, conversely, the host functionally regulates colonization through

resource availability in the root cells and rhizosphere (Graham, 2000). Studies utilizing nuclear

magnetic resonance (NMR) spectroscopy confirm that intercellular AM hyphae rapidly assimilate

hexoses, but extramatrical hyphae are incapable of taking up sugars (Douds et al. , 2000).

Inadequate P nutrition in the roots increases C-release into the apoplast from root cells because of

altered plasmalemma structure as a consequence of phospholipid depletion (Ratnayake et al.,

1978). Mycorrhizal colonization becomes self-limiting because improved phosphate availability in

roots provided by the mutualistic response restores membrane integrity and even restricts C flux

into the root apoplast and rhizosphere (Graham et al., 1981). Intercellular mycorrhizal colonization

acts further to reduce sugar leakage from the root cortex compared with the cortex of

nonmycorrhizal roots below the critical P concentration in tissues that affects membrane

permeability (Ratnayake et al., 1978). With attainment of P sufficiency in tissues, mycorrhizal

mediated decrease in sugar availability from roots is coincident with reduction in pathogen

colonization and damage (Graham & Menge, 1982; Graham & Egel, 1988).

The inability of external hyphae to assimilate sugars diminishes the role of extramatrical

hyphae as sites for C interactions. Only a small fraction (< 2%) of the total below-ground labeled

14C in mycorrhizal citrus roots is released into the rhizosphere and an even smaller fraction (<

0.2%) is attributable to release into the mycorrhizosphere (Eissenstat et al., 1993). Populations

and metabolic activity of Pseudomonas fluorescens are reduced in the hyphosphere of G.

intraradices compared to nonrhizosphere soil (Ravnskov et al., 1999). Thus, microorganisms

compete intensely for C in the hyphosphere as this arena is perhaps even more growth-limiting

than rhizosphere soil.

Functional role of mycorrhizas in relation to root pathogens in the field

Field evidence remains unconvincing that AM fungi substantially improve P relations and

growth of temperate crops in agroecosystems (McGonigle & Miller, 1996). Even in natural

systems, plants with fibrous root architecture show only marginal reduction in P acquisition when

their mycorrhizas are impaired by fungicides (West & Fitter Watkinson, 1993). This directs

attention to other functional attributes of mycorrhizas that might confer competitive advantage for

plants to maintain the symbiosis in the absence of substantial P benefit. In a temperate grassland

ecosystem, direct interaction of AM fungi, not P uptake, reduces the deleterious effects of the root

pathogenic fungi and thereby may increase plant fecundity (Newsham et al., 1994). Newsham et al

(1995) propose that root protection by AM fungi may be as important as nutritional benefits in

natural systems, though they do not specify a mechanism for the interaction of mycorrhizas and

root-infecting fungi. Their conclusion is derived from study of AM function in only a few plant

species under natural conditions, thus, the broader significance of direct mycorrhiza–pathogen

interactions requires much greater support from field experimentation.


- 169 -

Summary

Refined understanding of the exchanges of P, C and other nutrients in arbuscular

mycorrhizas and the mycorrhizosphere permits us better to answer the question ‘what do root

pathogens see in mycorrhizas?’ Larsen and Bodker (1994) employ neutral lipid fatty acids for more

precise quantification of the interaction of a root pathogen and an AM fungus than here-to-fore

possible. Moreover, these fatty acids give estimates of the ‘energy status’ of the interacting fungi,

as the signature acids comprise more than 50% of the storage lipid in each fungus. The

concomitant reduction in each fungus’s biomass and energy status provides preliminary evidence

for competition for resources between the obligate symbiont and the biotrophic pathogen. The

specificity of signature fatty acids for evaluation of direct interactions of selected microbes and

plant species should greatly facilitate studies, particularly under field conditions.

REFERENCES

1. Blee KA, Anderson AJ. 2000. Defense responses in plants to arbuscular mycorrhizal fungi. In: Podila GK, Douds Jr DD, eds. Current advances in mycorrhizae research . St. Paul,

MN, USA: The American Phytopahthological Society Press, 27–44.

2. Cordier C, Pzier MJ, Barea JM, Gianninazzi S, Gianniazzi-Pearson V. 1998. Cell defense responses associated with localized and systemic resistance to Phytophthora parasitica induced in tomato by an arbuscular mycorrhizal fungus. Molecular Plant–Microbe Interactions 11 : 1017–1028.

3. Douds Jr DD, Pfeffer PE, Shachar-Hill Y. 2000. Application of in vitro methods to study carbon uptake and transport by AM fungi. Plant and Soil 226 : 255–261.

4. Eissenstat DM, Graham JH, Syvertsen JP, Drouillard DL. 1993. Carbon economy of sour orange in relation to mycorrhizal colonization and phosphorus status. Annals of Botany 71 :

1–10.

5. Gerdemann JW. 1975. Vesicular–arbuscular mycorrhizae. In: Torrey JG, Clarkson DJ, eds. The development and function of roots . New York, USA: Academic Press, 575–591.

6. Graham JH. 2000. Assessing costs of arbuscular mycorrhizal symbiosis in agroecosystems. In: Podila GK, Douds Jr DD, eds. Current advances in mycorrhizae research . St. Paul, MN, USA: The American Phytopahthological Society Press, 127–140.

7. Graham JH, Egel DS. 1988. Phytophthora root development on mycorrhizal and phosphorus-fertilized nonmycorrhizal sweet orange seedlings. Plant Disease 72 : 611–614.

8. Graham JH, Leonard RT, Menge JA. 1981. Membrane-mediated decreases in root exudation responsible for for phosphorus inhibition of vesicular–arbuscular mycorrhiza formation. Plant Physiology 68 : 548–552.

9. Graham JH, Menge JA. 1982. Influence of vesicular–arbuscular mycorrhizae and soil phosphorus on take-all disease of wheat. Phytopathology 72 : 95–98.

10. Larsen J, Bodker L. 2001. Interactions between pea root-inhabiting fungi examined using signature fatty acids. New Phytologist 149: 487–493.

11. Lindermann RG. 1994. Role of VAM fungi in biocontrol. In: Pfleger FL, Lindermann RG, eds. Mycorrhizae and plant health . St. Paul, MN, USA: The American Phytopathological

Society Press, 1–25.

12. McGonigle TP, Miller MH. 1996. Mycorrhizae, phosphorus absorption and yield of maize in response to tillage. Soil Science Society of America Journal 60 : 856–1861.


- 170 -

13. Newsham KK, Fitter AH, Watkinson AR. 1994. Root pathogenic and arbuscular mycorrhizal fungi determine fecundity of asymptomatic plants in the field. Journal of Ecology 82 :

805–814.

14. Newsham KK, Fitter AH, Watkinson AR. 1995. Multi-functionality and biodiversity in arbuscular mycorrhizas. Trends in Ecology and Evolution 10 : 407–411.

15. Rhodes LH. 1980. The use of mycorrhizae in crop production systems. Outlook in Agriculture 10 :

275–281.

16. Ratnayake M, Leonard RT, Menge JA. 1978. Root exudation in relation to supply of phosphorus and its possible relevance to mycorrhizal formation. New Phytologist 81 : 543–552.

17. Ravnskov S, Nybroe O, Jakobsen I. 1999. Influence of an arbuscular mycorrhizal fungus on Pseudomonas fluorescens DF57 in rhizosphere and hyphosphere soil. New Phytologist 142 : 113–122.

18. Ross JP. 1972. Influence of endogone mycorrhiza on Phytophthora root rot of soybean. Phytopathology 62 : 896–897.

19. Schenck NC. 1981. Can mycorrhizae control root diseases? Plant Disease 65 : 230–234.

20. Schoenbeck F. 1979. Endomycorrhiza in relation to plant diseases. In: Schipper B, Gams W, eds. Soil-borne plant pathogens . New York, USA: Academic Press, 271–280.

21. Smith GS. 1988. The role of phosphorus nutrrition in interactions of vesicular–arbuscular mycorrhizal fungi with soilborne nematodes and fungi . Phytopathology 78 : 371–374.

22. West HM, Fitter Watkinson AR. 1993. Response of Vulpia ciliate ssp. Ambigua to removal of mycorrhizal infection and to phosphate application under natural conditions. Journal of Ecology 81 : 351–358.


- 171 -

Wheat Stem Rust Ug 99- A Threat to Food Security

Y.P. Sharma DWR, Regional Station, Flowerdale, Shimla

Wheat is grown on more than 200 million hectares of land and is a source of food and

livelihood for over a billion people in developing countries. In India it is the second important

cereal after rice, contributing substantially to the national food security by providing more than 50%

of the calories to the people who depend on it. In India, three different wheat namely bread

wheat, (T.aestivum), macaroni wheat (T.durum) and emmer / Khapli, (T.dicoccum) are under

commercial cultivation covering nearly 86, 12 and 2 percent area under the crop . The country

constitute six different growing agro-ecological zones having different soil profile, disease

spectrum and management practices.

Two zones viz. North Western Plains Zone (NWPZ) and North Eastern Plains Zone (NEPZ)

are most important.for contributing areas for national food basket for the country.

Wheat yields are adversely affected by various abiotic and biotic stresses throughout the

world. Of the biotic stresses wheat rusts are definitely and most important diseases that reduce

wheat yields. In India among all the three rusts i.e. leaf, stripe and stem are reducing the crop

yield to varying extent in different areas. Leaf and stripe rust are of regular appearance in most of

the wheat growing areas whereas stem rust is of economic significance in Peninsular (PZ),

Southern hills zone (SHZ) and Central zone (C.P.) In the past wheat rust used to cause an

average 10% yield loss, but through the release of resistant varieties, it is minimized to 2% .

Before the release to semi-dwarf wheat varieties epidemics of rusts were frequent and devastating

. Wheat rusts are being managed worldwide by planting resistant varieties of wheat. Though rust

management with fungicide is feasible but it is not cost effective besides causing chemical residue

problem which is not environmentally friendly.

Rust management using resistant varieties has faced the limited durability of resistance.

Resistance breeding at National and International level has been mostly based on deployment of

one or few genes. However these genes are race specific and function only if the infecting rust

population is of pathotype that lacks virulence with regard to those specific genes. Against the

rapid rate of change in the genetic make-up of rust populations most of wheat varieties are at

continuous risk of becoming susceptible to the selection of new virulent pathotypes.

Several commercial resistant varieties in India had also become susceptible to emergence

of new virulences like development of virulences of leaf rust against Sonalika

(45R31) and HD2285/ HD 2329 (109R63);(109R31); Stripe rust against Kalyansona (Pts

66S64, 70S64), 66S64-1), UP 2338/ CPAN 3004 (46S119) and PBW 343 (78S84) and stem rust

62G29 virulent on six Sr genes ( Sr5, Sr8a, Sr 9b, Sr 9e, Sr 11, Sr 28 ) in 1974 while 62G29-1

against additional virulence to one more gene Sr2 in 1989.

The emergence of Ug99 new virulent strain of stem rust detected in Uganda in 1999


- 172 -

named as Ug 99 has become a global threat to wheat production because of its virulence on Sr31

gene, which has been used in majority of cultivated wheat varieties in the world to resist stem rust

disease. Thus most of them popular wheat varieties of the world especially those in Asia are

vulnerable to this virulence.

World experienced a series of major epidemics of stripe rust due to break down of

Yellow rust resistance gene Yr9, present in several cultivars that were grown in South, West and

Central Asia . The virulent pathotypes of this rust moved from East Africa where it was first

detected through Yemen to near East and into Central Asia, Pakistan and India. This caused

crop losses to several hundred million and affected the livelihood of million of farmers. The

emergence of Ug99 is expected to becomes a similar potential global threat of wheat production

because 90% wheat varieties planted along its proposed migration route are susceptible to Ug99.

Since Ug99 was first identified in East Africa in 1999, it has spread to countries including the

Sudan, Yemen as most recently the Islamic Republic of Iran in the Near East in late 2007, The

arrival of Ug99 in the Near East poses a new and hightended risk to wheat production in

Afganistan, , Pakistan and India followed by the countries of Caucasus and Central Asia.

Because of specific characteristics of Ug99, it is considered a potential threat to wheat

crop in India. Its adaptability to cooler climates, high proliferation rate development of new

varients on other genes like Sr24, Sr36 and Sr30 which were resistant to Ug99, quick spread

following similar migration route as experienced earlier with Yr9 and Yr2 and cultivation of

approximately 48% of varieties with Sr31 like PBW 343 occupying more than six million hectare

area in NWPZ/ NEPZ of the country. It is a matter of great concern if adaptability of Ug99 infect

the wheat crop in Gangetic plains in India which contributes maximum wheat produce to National

food pool for public distribution system and food security.

Though emergence of Ug99 is a challenge to wheat Research Programme of India but a

strong net work of wheat programme through AICW & BIP have number of strengths to mitigate

this new threat. A regular monitoring system through conducting surveys of different wheat

growing belts of the country. Establishing trap nurseries in strategic locations and pathotype

analysis prevalent in different areas would help in keeping strict vigil on the introduction of disease.

The utility of the nursery can be improved by inclusion of variety, HD2189 which is at present

resistant to stem rust in India but susceptible to Ug99 and its variants. Its inclusion would help in

trapping migrating Ug99 and its variants with susceptible reaction in Indian territory.

Collaborate resistance screening programme is required. So far the studies revealed that

Ug99 does not exist in India, Therefore resistance screening can only be undertaken in Kenya

where the pathotype is prevalent. So far 442 wheat materials have been screened at Njaro

(Kenya) since 2005 and several varieties with resistance to Ug99 and its varieties have been

found. The screening has indicated existence of diverse resistance in some of the varieties which

is an encouraging sign to meet the threat. Multiplication of Ug99 resistant wheat material and its

distribution to wheat breeders in the Country.


- 173 -

Multiplication of breeders seed of already released varieties with resistance to Ug99. 450 tons of

breeder seed of 11 wheat varileties Viz. Gw273, GW322, Hi 1500, HD2781 MP 4010, HUW 510,

MACS 2846 (Durum), HI 8498 (Durum), UP 2338, DL-153-2 and HW 1085 was produced for

further multiplication.

International Cooperation:- Since disease spreads through wind is not restricted by

geographical boundries befooling quarantine restrictions. Therefore common stratigies for wheat

growing countries at International level are needed to keep the disease under check by developing

resistant varieties and monitoring the spread of disease systematically. At Global level wheat is a

staple food crop, its protection is important to ensure food security in the world.It is desirable to

involve diverse stem rust resistant genes to Ug99 and its varieties and their cultivation along the

proposed migration path to void serious epidemics of rusts.

India is a member of BGRI (Borlaug Global Rust Initative_ housed at the cornell University

which would integrate the outcomes techonologies/ research system of different countries.

Management of Ug99 is not difficult but requires concerted collaborative efforts of all the

concerned countries to overcome this threat to food security.


- 174 -

Management of Transboundary Movement of Pests

R.K. Khetarpal, V. Celia Chalam and Kavita Gupta Division of Plant Quarantine, National Bureau of Plant Genetic Resources, New Delhi-110 012

1. Introduction

Plant quarantine is a government endeavour enforced through legislative measures to

regulate the introduction of planting material, plant products, soil, living organisms etc. in order to

prevent inadvertent introduction of pests and pathogens harmful to the agriculture of a region and

if introduced, prevent their establishment and further spread. The devastating effects resulting

from diseases and pests introduced along with international movement of planting material,

agricultural produce and products are well documented (Khetarpal et al., 2006a). The Irish famine

of 1845, which forced the people to migrate en masse from Europe, was the result of almost total

failure of potato crop due to attack of late blight pathogen (Phytophthora infestans) introduced from

Central America. Coffee rust (Hemileia vastatrix) appeared in Sri Lanka in 1875 and reduced the

coffee production by >90% in 1889. The disease entered India in 1876 from Sri Lanka and within a

decade, the coffee industry of South India was badly affected.

Bulk import of seeds without proper phytosanitary measures, indiscriminate exchange of

germplasm and the distribution of seed by international agencies have increased the possibility of

dissemination of pests in areas previously considered pest-free (Kahn, 1989; Khetarpal et al.,

2006a). Further, the threat may become severe, if more virulent strains or races or biotypes of the

pest are introduced into previously pest-free areas of crop production.

Management of transboundary movement of pests for safe exchange of genetic resources

and trade especially now under the gamut of International Agreements of World Trade

Organization (WTO) is essential in order to remain competitive.

2. Exclusion of Exotic Pests through Quarantine

2.1. National Scenario

As early as in 1914, the Government of India passed a comprehensive Act, known as

Destructive Insects and Pests (DIP) Act, to regulate or prohibit the import of any article into India

likely to carry any pest that may be destructive to any crop, or from one state to another. The DIP

Act has since undergone several amendments. In October 1988, New Policy on Seed

Development was announced, liberalizing the import of seeds and other planting material. In view

of this, Plants, Fruits and Seeds (Regulation of import into India) Order (PFS Order) first

promulgated in 1984 was revised in 1989. The PFS Order was further revised in the light of World

Trade Organization (WTO) Agreements and the Plant Quarantine (Regulation of Import into India)

Order 2003 [hereafter referred to as PQ Order], came into force on January 1, 2004 to comply with

the Agreement on Application of Sanitary and Phytosanitary (SPS) Measures (Khetarpal et al.,

2006a). Till October 2008, 12 amendments to the PQ Order were notified revising definitions,

clarifying specific queries raised by quarantine authorities of various countries, with revised lists of


- 175 -

crops under the Schedules VI, VII and quarantine weed species under Schedule VIII. The revised

list under Schedules VI and VII (including proposals made in four draft amendments) now include

641 and 288 crops/ commodities, respectively. The Schedule VIII now include 61 quarantine weed

species. The PQ Order ensures the incorporation of “Additional/ Special Declarations” for import

commodities free from quarantine pests, on the basis of pest risk analysis (PRA) following

international norms, particularly for seed/ planting material

(http://www.agricoop.nic.in/gazette.htm).

The Directorate of Plant Protection, Quarantine and Storage (DPPQS) under the Ministry of

Agriculture is responsible for enforcing quarantine regulations. The quarantine processing of bulk

consignments of grain/ pulses etc. for consumption and seed/ planting material for sowing are

undertaken by its 35 Plant Quarantine Stations located in different parts of the country and many

pests were intercepted in imported consignments (http://www.plantquarantineindia.org/

docfiles/appendix-8.htm). Import of bulk material for sowing/ planting purposes are allowed only

through five Plant Quarantine Stations. There are 41 Inspection Authorities who inspect the

consignment being grown in isolation in different parts of the country.

The National Bureau of Plant Genetic Resources (NBPGR), has been empowered under

the PQ Order to handle quarantine processing of germplasm including transgenic planting material

imported for research purposes into the country by both public and private sectors. NBPGR has

developed well-equipped laboratories and green house complex. A containment facility of CL-4

level has been established for processing transgenics. At NBPGR, adopting a workable strategy, a

number of pests of great economic and quarantine importance have been intercepted on exotic

material, many of which are yet not reported from India viz., insects like Acanthoscelides obtectus

in Cajanus cajan, Anthonomus grandis in Gossypium spp., Ephestis elutella in Macadamia nuts

and Vigna spp., Quadrastichodella eucalytii in Eucalyptus, nematodes like Heterodera schachtii,

Ditylenchus dipsaci, D. destructor, Rhadinaphelenchus cocophilus, etc. in soil clods and plant

debris, fungi like Claviceps purpurea in seeds of wheat and barley, Peronospora manshurica on

soybean, Fusarium nivale on wheat, barley and Aegilops, Uromyces betae on sugarbeet, bacteria

like Xanthomonas campestris pv. campestris on Brassica spp. and viruses like Barley stripe

mosaic virus in barley, Cherry leaf roll virus on French bean, Cowpea mottle virus in cowpea, Pea

seed borne mosaic virus in broad bean, Tomato black ring virus on cowpea and French bean, etc.

(Khetarpal et al., 2006a; Chalam and Khetarpal, 2008).

If not intercepted, some of the above quarantine pests could have been introduced into our

agricultural fields and caused havoc to our productions. In all these cases the harvest from pest-

free plants was only used for further distribution and conservation. Thus, apart from eliminating the

introduction of exotic pests from our crop improvement programmes, the harvest obtained from

pest-free plants ensured conservation of pest-free exotic germplasm in the National Genebank.

2.2. International Scenario

The recent trade related developments in International activities and the thrust of the WTO


- 176 -

Agreements and the Convention on Biological Diversity (CBD) imply that countries need to update

their quarantine or plant health related services to facilitate pest-free import/ export.

The establishment of the WTO in 1995 has provided unlimited opportunities for

international trade of agricultural products. History has witnessed the devastating effects resulting

from diseases and pests introduced along with the international movement of planting materials,

agricultural produce and products. However, legal standards in the form of SPS Measures were

developed only after the establishment of WTO. The SPS Agreement recognizes the government’s

rights to take SPS measures but stipulates that they must be based on science, applied only to the

extent necessary to protect human, animal or plant life or health and not unjustifiably discriminate

between members where identical or similar conditions prevail (http//:www.wto.org, Khetarpal and

Gupta, 2002).

SPS measures are defined as any measure applied within the territory of the Member State to:

a) protect animal or plant life or health from the risk of entry, establishment or spread of pests,

diseases, disease- carrying/ causing organisms;

b) protect human or animal life or health from risks arising from additives, contaminants, toxins

or disease causing organisms in food, beverages or feedstuffs;

c) protect human life or health from risks arising from diseases carried by animals, plants or

their products, or from the entry, establishment /spread of pests; or

d) prevent or limit other damage from the entry, establishment or spread of pests.

It explicitly refers to three standard-setting international organizations -International Plant

Protection Convention (IPPC) of Food and Agriculture Organization (FAO) of the United Nations

for plant health, World Organization for Animal Health (OIE) for animal health and the Codex

Alimentarius Commission of Joint FAO/ WHO for food and feed related standards. The IPPC

develops the International Standards for Phytosanitary Measures (ISPMs) to provide guidelines on

pest prevention, detection and eradication. To date, twenty nine standards have been developed

and several others are at different stages of development.

Prior to the establishment of WTO, governments on a voluntary basis could adopt

international standards, guidelines, recommendations and other advisory texts. Although these

norms remain voluntary, a new status has been conferred upon them by the SPS Agreement. A

WTO Member adopting such norms is presumed to be in full compliance with the SPS Agreement.

Also, the Convention on Biological Diversity (CBD) came up in 1992 wherein the

quarantine related commitments made by parties are to regulate, manage or control risks

associated with use and release of living modified organisms likely to have adverse environmental

effects and prevent introduction of alien invasive species which could threaten native ecosystems

or species (http://www.cbd.org). In India, the Ministry of Environment and Forests is the nodal

agency dealing with Invasive Alien Species (IAS) for negotiations with CBD, but, it is the Ministry

of Agriculture which is the key body dealing with their quarantine, survey and control. There is a

need for a cohesive policy and action plan to deal with IAS (Gupta and Khetarpal, 2006).


- 177 -

3. Seed Health Testing for Management of Transboundary Movement of Pests

Infected or contaminated seed is a primary source of inoculum for a large number of

destructive diseases of important food, fodder and fiber crops (Neergaard, 1977) and is an

excellent carrier for the dissemination of phytopathogenic agents to long geographical distances.

International Seed Testing Association (ISTA), European and Mediterranean Plant Protection

Organization (EPPO) and National Seed Health System (NSHS) of the US among others

recommend methods for the assessment of seed health. Also, International Seed Health Initiative

(ISHI) established in 1994 with the members from private industry (France, Israel, Japan, The

Netherlands and USA) is involved in development of seed health testing methods and the methods

developed by ISHI are validated by ISTA. ISTA issues International Certificates to seed lots that

have been tested in its approved laboratory. Issuance of the certificate allows the seed to be

traded freely; however, it may not be, accepted by organizations or countries universally. India is a

member of ISTA and attempts to follow its standards for certification.

The selection of a diagnostic method for evaluating seed health depends on the host to be

tested and the type of pest that may be carried in the seed. The techniques may vary considerably

in specificity and a distinction can be made between generalized method revealing a wide range of

pests and more or less specialized technique designated to detect a particular species, pathogenic

race or strain or biotype. The various techniques, conventional and modern, that are employed for

seed health testing of different pests have been reviewed (Khetarpal, 2004) and are summarized

in Table 1.

Table 1. Summary of various techniques for detecting seed-transmitted pathogens and insect pests

Techniques Fungi Bacteria Virus Insects Nematodes

Conventional

Dry seed examination + + + + +

Seed washing test + + - - -

Soaked seed test + - - - +

Whole embryo test + - - - -

Incubation tests + + - - -

Phage sensitivity test - + - - -

Staining of inclusion bodies - - + - -

Electron microscopy - - + - -

Growing-on test + + + - -

Infectivity test + + + - -

X ray radiography - - - + -

Transparency test - - - + -

Serological

Enzyme-linked immunosorbent assay (ELISA) - + + - -

Dot-immunobinding assay (DIBA) - - + - -

Immunosorbent electron microscopy (ISEM) - - + - -

Molecular

Polymerase chain reaction (PCR) + + - - +

Reverse transcription-PCR (RT-PCR) - - + - -

Immunocapture-RT-PCR (IC-RT-PCR) - - + - -

Real-time PCR + + - - +

Real-time RT-PCR - - + - -


- 178 -

4. Seed Certification for Management of Transboundary Movement of Pests

Seed certification for a crop comprises of legal norms to be qualified for ensuring genetic

identity, physical purity, germinability and freedom from seed-transmitted pathogens and weeds.

ISTA and Association of Official Seed Certifying Agencies (AOSCA) among others have

introduced minimum seed certification standards with the objective of developing certification

programmes for seed-transmitted pathogens is to ensure the level of infection of a seed lot.

Besides, the seed material under international exchange needs to be certified as pest-free to

minimize the risk associated with the introduction of exotic pests or virulent strains/ biotypes to an

area in which they have not previously been reported. Similarly, conservation of pest-free seeds of

a crop in Gene Banks will minimize the spread of "germplasm-borne" pests.

For quality control of seeds a tolerance limit for the disease has to be fixed. The tolerance

limit refers to the inoculum threshold that can be tolerated in an agricultural context. For

determining the inoculum threshold, there is a need to collect detailed epidemiological information

on the seed transmission rate, the degree of susceptibility of various cultivars, the rate and

intensity of field spread (by vectors in case of viruses) in relation to climatic conditions, the

resulting percentage of infected plants in the field and yield reduction (Maury et al., 1985). Once

the tolerance limit is determined, the methodology has to be developed for quality control.

However, for most of the seed-borne pests not much serious work has been done in this direction.

4.1. Seed Health Certification in India

India has developed a seed improvement programme during 1960s setting up National

Seeds Corporation (NSC) in 1963, State Farms Corporation of India (SFCI) and Tarai

Development Corporation (TDC) in 1969. In order to maintain quality of seeds during production

and distribution stages, Indian Seeds Act (1966) was enacted. Central Seed Certification Board

(CSCB) was also set up in 1972 to advise the Central and State Governments on all matters

related to seed certification. Since then, seed industry experienced phenomenal growth. Nineteen

seed certification agencies have been set up and area under seed certification which was few

hundred hectares in the early stage of seed certification has increased to >5,00,000 hectares.

In 1988, CSCB brought out the Minimum Seed Certification Standards (MSCS) for 102

crops and a supplement was brought out in 2002 confirming the modifications/ revision in MSCS of

18 crops including 8 new crops. MSCS prescribes the maximum permissible levels for certain

designated seed-borne diseases i.e., per cent affected plants in the seed crop and infected seeds

in the seed lot. Though seed health certification in India is a part of the seed certification

programme operating under the provisions of the Seeds Act, in most of the cases, it is only based

on field-stage standards. Out of 110 crops for which seed certification standards are prescribed,

seed health standards for seed-borne diseases are available for 43 crops (57 fungal diseases, 17

bacterial diseases, 14 viral diseases and one phytoplasma disease) by seed crop inspection at

field stage, for two crops (2 fungal diseases and 2 bacterial diseases) by seed sample analysis at

seed stage and for seven crops (21 fungal diseases, 2 bacterial diseases, one nematode disease,


- 179 -

one bacterial + nematode complex and 2 viral diseases) by both field inspection and seed

analysis. Thus, only in 9 crops including potato and sweet potato, post-harvest pathology is related

to seed certification (Khetarpal et al., 2006b).

Seed certification as such is voluntary. About 50% of the seed produced/ distributed passes

through certification for the designated seed-borne diseases in the field and/ or seed stages

depending upon the stage for which certain maximum permissible level is prescribed in the

MSCS.

Seed produced/ handled outside certification is governed by the internal quality control

(QC) standards/ procedures of the concerned firm, institution or individual, which vary between

firms. No authentic information is available about the internal QC arrangements of firms outside

certification. The Government of India’s standards and procedures seem to form the basis for the

QC systems adopted for seed production/ handling outside certification. Unfortunately so far,

emphasis on seed health especially seed-borne diseases per se is only secondary to

varietal purity and physiological quality.

The Seeds Act (1966) and the New Policy on Seed Development (1988), formed the basis

of promotion and regulation of the seed industry. Globalization and economic liberalization have

now opened up several new opportunities as well as challenges. The National Seeds Policy (2002)

has come into force which gives renewed quality assurance mechanisms.

5. Challenges in Excluding Exotic Pests through Quarantine

The issues related to quarantine methodology were analyzed/ reviewed recently by

Khetarpal (2004). The challenge prior to import is preparedness for pest risk analysis (PRA). PRA

is now mandatory for import of new commodities into India. The import permit will not be issued

for the commodities not covered under the Schedule-V, VI and VII under the PQ Order. Hence, for

import of new commodities in bulk for sowing/ planting, the importer should apply to the Plant

Protection Adviser to the Government of India for conducting PRA. In case of germplasm, Import

Permit shall be issued by the Director, NBPGR, after conducting PRA based on international

standards (http://agricoop.nic.in/Gazette/Psss2007.pdf).

The ISPM-2, ISPM-11 and ISPM-21 deals with the guidelines for conducting PRA for

quarantine pests and regulated non-quarantine pests (http://www.ippc.int/ipp/en/standards.htm).

The process requires detailed information on pest scenario in both countries importing and

exporting the commodity. Efforts to develop a database for endemic pests has been made by the

Plant Quarantine Station in Chennai and NBPGR has compiled pests of quarantine significance for

cereals (Dev et al., 2005), grain legumes (Chalam et al., unpublished) and a check-list for viruses

in grain legumes (Kumar et al., 1994). The Crop Protection Compendium of CAB International,

UK, is a useful tool for global pest data (CAB International, 2007).

As we face challenges to crops from intentional or unintentional introductions of pests,

speed and accuracy of detection become paramount. Intense efforts are under way to improve

detection techniques. The size of consignment received is very critical in quarantine from


- 180 -

processing point of view. Bulk seed samples of seed lots need to be tested by drawing workable

samples as per norms. The prescribed sampling procedures need to be followed strictly and there

is a need to develop/ adapt protocols for batch testing, instead of individual seed analysis (Maury

et al., 1985). On the other hand, germplasm samples are usually received as a few seeds/ sample

and thus, it is often not possible to do sampling because of few seeds and also because of the fact

that a part of the seed is also to be kept as voucher sample in the National Genebank in India

apart from the pest-free part that has to be released. Hence, extreme precaution is needed to

ensure that the result obtained in the test was not denoting a false positive or a false negative

sample. Removal of exotic viruses from germplasm by growing in PEQ greenhouses inevitably

causes a delay in the release of seeds as it takes one crop season to release the harvest only

from the indexed virus-free plants. Samples received after the stipulated sowing time would

require the indenter to wait for another season. Non-destructive testing of the seeds could shorten

this time and therefore, more attention needs to be given to non-destructive techniques wherever

possible (Khetarpal, 2004; Chalam and Khetarpal, 2008, Khetarpal and Gupta, 2008).

6. Perspectives

Detection and diagnosis of pests are crucial for trade and for exchange of plant genetic

resources. But, the level of confidence, knowledge and accuracy on the part of the workers need

to be improved for precise detection and diagnosis. Training is required for quarantine officials,

germplasm curators and scientists who are involved in assessing the conformity to the

international standards especially in developing and countries with economy in transition. There is

also a need to seek technical assistance of international agencies in the area of human resource

development. Compared to the other seed quality tests, seed health testing requires technically

more advanced equipment, reagents etc. Accreditation of few well-established laboratories would

offer a reasonable solution for reduction of costs. In our country we have few laboratories, which

are well equipped and have trained experts to deal with diagnostic aspects of seed health

management. Such laboratories need to be accredited on priority to enhance their credibility at

international level.

On the other hand, the declarations mentioned on Phytosanitary Certificate should not

deviate, as it is often found at NBPGR, that the consignment is infected by pests although the

consignment is certified by the exporting countries as pest-free in case of germplasm. At NBPGR,

the legume germplasm was found to be infected by 20 viruses when tested by ELISA and in some

cases by electron microscopy. Jones (1987) emphasizes the need for disease-free seed stocks in

germplasm collections to enable countries with less sophisticated quarantine systems to import

disease-free seeds, intended for improving crop production and not for introducing new

pathological problems. However, this is not a problem in case of bulk consignments with the trade

being under the gamut of Sanitary and Phytosanitary Agreement of WTO, where in the

consignments can be justifiably rejected, if the exporting country does not follow the importing

country’s requirements.


- 181 -

Strict regulatory measures together with growing new introductions under containment or

isolation and collection of seeds from only disease-free plants must be followed to eliminate the risk

of introducing seed-transmitted pathogens/ their strains if any. Conservation of pest-free seeds of a

crop in Genebanks will minimize the spread of "germplasm-borne" pests as these materials are

multiplied and exchanged worldwide. The countries should take note of a series of technical

guidelines for the safe movement of germplasm prepared by FAO/ Bioversity International (formerly

IPGRI), Rome (Frison and Diekmann, 1998) and Bioversity International needs to support an

effective quarantine networking on PGR under exchange and conservation.

Database on all seed-borne pests, including information on host range, geographical

distribution, strains, etc. should be made available for its use as a ready reckoner by the

quarantine personnel. There is a need to have antisera for all the seed-transmitted viruses in the

quarantine laboratories to facilitate the interception of exotic viruses and their strains. Information

access and exchange on seed health certification and quarantine are crucial for effective working.

Also regional working groups of experts for detection and diagnosis of pests need to be formed to

explore future cooperation in terms of sharing of expertise and facilities, for example in South Asia

where the borders are contiguous. This would help in avoiding the introduction of pests not known

in the region and also restrict movement of pests within the region.

The importance of quarantine has increased manifold in the WTO regime and adopting not

only the appropriate technique but also the right strategy for pest detection and diagnosis would go

a long way in ensuring pest-free exchange of germplasm and trade, and is considered the best

strategy for managing transboundary movement of pests.

REFERENCES

1. CAB International. 2007. Crop Protection Compendium, Wallingford, UK: CAB International.

2. Chalam VC and RK Khetarpal. 2008. A critical appraisal of challenges in exclusion of plant viruses during transboundary movement of seeds. Indian Journal of Virology 19: 49-60 (In Press).

3. Dev U, RK Khetarpal, PC Agarwal, A Lal, ML Kapur, K Gupta and DB Parakh. (eds). 2005. Pests of Quarantine Significance in Cereals. National Bureau of Plant Genetic Resources, New Delhi, India, p 142.

4. Frison E and M Diekmann. 1998. IPGRI’s role in controlling viral diseases in plant germplasm. pp 230-236. In: A Hadidi, RK Khetarpal and H Koganezawa (eds.) Plant Virus Disease Control, American Phytopathological Society Press, St. Paul, Minnesota, USA.

5. Gupta K and S Khetarpal. 2006. Regulatory measures dealing with invasive alien species: Global and national scenario. pp 169-185. In: LC Rai and JP Gaur (eds.) Invasive Alien Species and Biodiversity in India, Banaras Hindu University, Department of Botany, Centre of Advanced Study, Varanasi, India.

6. Jones DR. 1987. Seedborne diseases and the international transfer of plant genetic resources: an Australian perspective. Seed Science and Technology 15: 765-776.

7. Kahn RP. 1989. Plant Protection and Quarantine: Selected Pests and Pathogens of Quarantine Significance. Vol II. CRC Press Inc. Florida, 265 p.

8. Khetarpal RK. 2004. A critical appraisal of seed health certification and transboundary movement of seeds under WTO regime. Indian Phytopathology 57: 408-421.


- 182 -

9. Khetarpal RK, A Lal, KS Varaprasad, PC Agarwal, S Bhalla, VC Chalam and K Gupta. 2006a. Quarantine for safe exchange of plant genetic resources. pp 83-108 In: AK Singh, Kalyani Srinivasan, Sanjeev Saxena and BS Dhillon (eds.) Hundred Years of Plant Genetic Resources Management in India, National Bureau of Plant Genetic Resources, New Delhi, India.

10. Khetarpal RK and K Gupta. 2002. Implications of sanitary and phytosanitary agreement of WTO on plant protection in India. Annual Review of Plant Pathology 1: 1-26.

11. Khetarpal RK and K Gupta. 2008. Plant quarantine in India in the wake of international agreements: A review. Review of Plant Pathology 4: 367-391.

12. Khetarpal RK, V Sankaran, VC Chalam and K Gupta. 2006b. Seed health testing for certification and SPS/ WTO requirements. pp 239-258 In: G Kalloo, SK Jain, AK Vani and U Srivastava (eds.) Seed: A Global Perspective, Indian Society of Seed Technology, New Delhi, India, 312 p.

13. Kumar CA, RK Khetarpal, DB Parakh, S Singh and R Nath. 1994. Check list on seed-transmitted viruses: leguminous hosts. Technical Bulletin, New Delhi, India, National Bureau of Plant Genetic Resources, 14 p.

14. Maury Y, C Duby, JM Bossennec and G Boudazin. 1985. Group analysis using ELISA: Determination of the level of transmission of soybean mosaic virus in soybean seed: Seed group size and seed decortication. Agronomie 7: 225-230.

15. Neergaard P. 1977. Seed Pathology Volume I and II. Macmillian, London, 1187 p.


- 183 -

Pathogen Population Considerations in Developing Durable Disease Resistance: A Case Study of Rice Blast Pathosystem

J. Kumar

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand) Rice (Oryza sativa L.) is a staple food for over 2 billion people, providing 20% of human

food calories. “Blast”, caused by the heterothallic ascomycete Magnaporthe grisea (Hebert) Barr.

(anamorphe : Pyricularia grisea Sacc.) is the most important disease of rice and can cause severe

losses in most rice-growing environments . Although only known to reproduce asexually in nature,

the pathogen is notorious for its pathotypic diversity. Disease resistant rice cultivars are the

preferred means of blast management, considering that most rice farmers are poor and that

effective fungicides are quite costly. However, resistance in such cultivars is frequently short-lived.

Typically, a variety released as blast-resistant shows signs of susceptibility after only very few

seasons of cultivation in blast-prone environments.

Resistance “breakdown” is usually ascribed to extreme diversity and/or virulence variability in

the pathogen. In the case of extreme diversity, it has been proposed that much of the observed

resistance breakdown resulted from simple “escape” due to inadequate challenge in screening

nurseries. That is, either because conditions are not suitable for disease development, or if some

pathotypes are so rare as to not encounter a compatible line, lines may be incorrectly interpreted to

be `resistant'. As a breeding line is multiplied for release and eventually planted over large areas,

chances increase for encounter between compatible pathotypes and the new variety. With a large

host population the previously rare pathotype reproduces rapidly, and the observed `new'

susceptibility of the cultivar is interpreted as a resistance `breakdown'.

There is some evidence for escape being an important phenomenon in the lack of durability of

blast resistance. By conducting a blast resistance breeding program in a site with a highly diverse

pathogen population and an environment that supports continuous blast epidemics, durably resistant

cultivars could be developed. One such cultivar, Oryzica Llanos 5, has been grown continuously over

thousands of hectares for over 15 seasons in a severely blast-prone environment. Furthermore, it

has been evaluated in a number of countries across the world and found to be highly resistant in all

sites.

The question of pathotypic variation has long been controversial. At one extreme the

pathogen was described as hypervariable, with the capacity to generate a seemingly endless array

of new pathotypes from a single asexual spore. Thus, varieties evaluated for resistance to a single

pathotype would be exposed to an infinite range of pathogenic variation once released into the

field. A variety stood little chance of surviving under the onslaught of such variation, and the

reasonable conclusion was that race-specific resistance to the pathogen could not yield durable

resistance. This led to a major effort to develop race non-specific, or partial, resistance. At the

other extreme, the pathogen was described as completely stable, with no new races generated


- 184 -

even after years of culture in the laboratory. It is noteworthy that the proponents of hypervariability

worked with isolates from Asia (the center of origin of rice), recently recovered from the field, while

proponents of stability worked largely with isolates from the US (where rice was introduced only a

few hundred years earlier) and that had been in culture for a number of years.

Blast populations are very diverse, regardless of the mechanisms (genetic or otherwise)

that generated the diversity, and the design of most breeding programs is such that a blast-

resistant variety is simply not exposed to pathogenic variants that it would likely encounter under

production conditions. In other words, real-world rice varieties would be exposed to populations of

the pathogen, not just one or two races.

Virulence variation in pathogen populations

Plant pathologists and plant breeders have long understood the importance of pathogen

variation to the effectiveness and durability of host resistance. Pathogen genotypes can interact

with specific host genotypes leading to the "breakdown" of resistance within very short periods of

time. Detection of pathogen variation has traditionally relied upon the identification of virulence

variation (races) in the pathogen population by inoculating a sample of pathogen isolates on a

series of hosts with defined resistance genes (differentials) and observing the resulting compatible

or incompatible disease phenotype. This approach to monitoring pathogen populations has been

tremendously valuable in the development and deployment of host resistance, and has provided

important insights into the evolution of pathogen populations in response to selection by host

resistance genes. Pathotype monitoring is still used extensively in many pathosystems today and

continues to provide timely information about the structure of pathogen populations that is relevant

to breeding programs and resistance deployment.

Limitations on the use of virulence phenotype

Despite the obvious value of pathotype data, the use of virulence phenotypes to assess

genetic variation in plant pathogens has several important limitations. Host differential lines used in

virulence assays are often poorly defined genetically. A common set of differentials must be used

among labs to obtain comparable data, and assays are subject to environmental variation. A more

important limitation is that virulence variation in plant pathogens is almost always determined in

terms of virulence phenotype rather than genotype, which means that frequencies of virulence

genes cannot be estimated from these assays. This lack of genetic information coupled with the

fact that virulence phenotypes are subject to strong selection by the host limits the value of

virulence markers as population genetics tools.

Molecular markers in pathogen population analysis

Lately, plant pathologists interested in genetic variation in pathogen populations have

adopted the use of molecular markers as population genetics tools. Motivating this shift has been

the availability of a myriad of molecular techniques which makes the quantification of genetic

variation a relatively straightforward endeavor. Molecular markers such as allozymes , restriction

fragment length polymorphisms (RFLP) and random amplified polymorphic DNA (RAPD) have


- 185 -

been extensively used to characterize pathogen populations. More recently, amplified fragment

length polymorphisms (AFLP) have proven to be highly polymorphic and robust markers and will

likely be used extensively with plant pathogenic fungi in the future. In contrast to virulence and

fungicide resistance markers, molecular markers are presumed to be selectively neutral and

therefore may be used to study evolutionary processes in addition to selection.

The discovery of a neutral repetitive DNA sequence, MGR (for Magnaporthe grisea repeat)

in the rice blast pathogen in the late 1980s provided a means of analyzing populations

independently of the pathogenicity of the constituent isolates. The similarity of the MGR

"fingerprints" generated by analyzing the DNA of different isolates permitted an estimate of their

relatedness. Initial analysis of archival US P. grisea isolates revealed a direct relationship between

fingerprint type (subsequently referred to as lineages) and pathogenic races . Application of this

analytical tool to the Santa Rosa population yielded a less direct, but intriguing, relationship

between lineage and race: Sets of closely related races fall within a single lineage and the race

constitution of lineages differed. Furthermore, in what had been described as an extremely race-

diverse population, all isolates could be grouped into only six lineages. This led to the suggestion

that rice breeding could focus on selecting for cultivars that combined resistance that was effective

against the virulence spectrum of all lineages in a target population.

Lineage exclusion

This breeding approach, referred to as "lineage exclusion", assumes that P. grisea

populations are comprised of a few number of discrete lineages and that these lineages have

different and stable virulence spectra. These assumptions were tested in two populations from

blast resistance screening nurseries in the Philippines. It was found that , as in Colombia, there

were relatively few lineages comprising the populations . Analysis of lineage virulence spectra (i.e.,

the virulence of isolates on sets of isolates with known and different resistance) revealed that they

were indeed different. "Composite pathotypes" could be created for a lineage by considering any

compatibility within a lineage as reflecting the virulence capacity of that lineage. Comparing the

composite pathotypes of all the lineages of a population could predict what combination of

resistance would be effective across the entire population. In the case of the Philippines, a

combination of resistance genes Pi-1 and Pi Z5 (Pi-2) should yield resistance effective across all

lineages.

A similar analysis in Santa Rosa (Colombia) also predicted that the same two genes should

yield broad-spectrum resistance. This was tested by crossing two sources of resistance and then

evaluating the progeny in the field (exposing them to a diverse, well-characterized population) and

in the greenhouse (exposing them to isolates representing the full virulence spectrum in all

lineages in the population). As expected, progeny resulted with full spectrum resistance in both

greenhouse and field evaluations. Based on this positive result, parents in crosses for blast

resistance in Santa Rosa have been selected to combine complementary resistance. This has

yielded an significant increase in the efficiency of the breeding programs.


- 186 -

How effective can lineage exclusion be as a breeding tool for obtaining durable blast

resistance world-wide? A few critical issues suggest that with present technology, all areas may

not be suitable for its adoption. The situations in the Philippines and Santa Rosa may be

somewhat atypical in that these populations are from areas where modern varieties have been

grown and, because of a bottleneck effect of earlier deployed blast resistance, the pathogen

population may be much simpler than those populations in other rice-growing regions. i.e. if

populations are very complex it could be practically impossible to characterize the virulence

spectra of all lineages. Furthermore, for lineage exclusion to yield durable resistance, lineages

should be genetically isolated from one another so that virulence genes cannot be exchanged

among lineages.

A population analysis of P. grisea from a traditional rice-growing area of northeast Thailand

revealed a very complex population: 49 lineages were identified from 527 isolates, and most were

represented by only one or a few isolates . No obvious relationships between pathotype and

lineage was discerned within these samples using either lines near-isogenic for resistance genes

or cultivars with known resistance. Very high lineage diversity was also observed in the Indian

Himalayas and very high pathotypic diversity was observed in the Himalayan Kingdom of Bhutan,

although the corresponding lineage data are sketchy. It would be impossible to determine the

virulence spectrum of lineages comprising these populations. The problems however

notwithstanding, the analysis of the NE Thailand population revealed the same complementary

effectiveness of resistance genes Pi 1 and Pi z5.

An important assumption of the lineage exclusion approach is that there is no gene flow

across or genetic recombination among lineages. Several lines of evidence suggest that this may

not be the case in some areas. Reports of sexually fertile field isolates from India , China , and

Thailand indicate that the capacity for sexual recombination exists in nature. Population structure

and dynamics of Indian Himalayan populations are consistent with sexual recombination having

influenced populations there . There is also the possibility that horizontal flow of genes, including

those mediating resistance to entire lineages, can occur across lineages via non-sexual, or

parasexual, means .

Despite indications that there may be very large areas over which a population analysis-

based lineage exclusion breeding strategies may not be appropriate, there is ample evidence that

population analyses can yield valuable dividends. First, in most cases examination of the virulence

spectra of the most common lineages should indicate to breeders which crosses are unlikely to

yield durable blast resistance, thus increasing their efficiency. Second, the repeated conclusion

that the gene combination Pi 1 and Pi z5 is effective across very different populations suggests

there is something fundamentally limiting to P. grisea carrying compatibility to both genes

simultaneously. As more blast resistance genes are identified and placed in near-isogenic

backgrounds population analyses will enable us to identify other broadly effective gene

combinations. Finally, there are large and important rice growing areas where P. grisea


- 187 -

populations are relatively simple. These may be where rice has only recently been introduced, or

where very large areas have been planted to a few varieties carrying several major resistance

genes. Breeding strategies for these areas should be adjusted accordingly.

REFERENCES

1. Correa-Victoria, F.J., Zeigler, R.S. 1995. Stability of partial and complete resistance in Rice to Pyricularia grisea under rainfed upland conditions in eastern Colombia. Phytopathology 85:977-982.

2. Correa-Victoria, F.J., and Zeigler, R.S. 1993. Pathogenic variability in Pyricularia grisea at a rice blast "hot spot" breeding site in eastern Columbia. Plant Disease 77:1029-1035.

3. Kumar, J., Nelson, R. J., and Zeigler R. S., 1996. Population structure of Magnaporthe grisea in the traditional Himalayan rice system. In: Rice Genetics III. IRRI-CABI, Los Banos, Philippines, pp 963- 969.

4. Kumar, J., Nelson, R.J., and Zeigler, R.S. 1999. Population structure and dynamics of Magnaporthe grisea in the Indian Himalayas. Genetics 152:971-984.

5. Kumar, J. and Zeigler, R.S. 2000.Genetic diversity and evidence for recombination in

6. Himalayan populations of Magnaporthe grisea. In: Proceedings of the International

7. Conference on Integrated Plant Disease Management for Sustainable Agriculture. Vol. I.

8. Indian Phytopathology Society, IARI New Delhi., pp. 127-134.

9. Leung, H., R. J. Nelson, and J. E. Leach. 1993. Population structure of plant pathogenic fungi and bacteria. Advances in Plant Pathology 10:157-205.

10. Milgroom, M. G., and W. E. Fry. 1997. Contributions of population genetics to plant disease epidemiology and management. Advances in Botanical Research 24:1-30.

11. Zeigler, R.S. 1998. Recombination in Magnaprthe grisea. Annual Review of Phytopathology 36:249-276.

12. Zeigler, R.S., Scott, R.P., Leung, H., Bordeos, A.A., Kumar, J., and Nelson, R.J. 1997. Evidence of parasexual exchange of DNA in the rice blast fungus challenges its exclusive clonality. Phytopathology 87:284-294.

13. Zeigler, R.S., Tohme, J., Nelson, R. J., Levy, M., Correa, F. J. 1994. Lineage exclusion: A proposal for linking blast population analysis to resistance breeding. pp. 267-292 in Rice Blast Disease, R. S. Zeigler, P.S. Teng, S. A. Leong (eds.) Commonwealth Agricultural Bureaux, Walllingford, UK.


- 188 -

Role of PGPR in Plant Disease Management

Yogesh K. Negi Deptt. of Microbiology, SBS PG Institute of Biomedical Sci and Res., Balawala, Dehradun (Uttarakhand)

Biological control is defined as the mechanism involved in the management of disease

symptoms and reduction of pathogen inoculum on plants, a treatment mediated through the use of

organisms other than man.

Currently to prevent these crop losses, farmers resort to indiscriminate, and mostly

irrelevant crop protection measures, which over the time, have led to serious situations of

resurgence in pest populations, increased crop losses and importantly, environment including

ground water and foodstuff pollution. There can be cases of resistance development in pest

population as well. Use of beneficial rhizobacteria (Plant Growth Promoting Rhizobacteria) having

biocontrol (BCA) and plant growth promoting (PGP) activities is a viable alternative to minimize the

use of synthetic chemicals and their hazardous effects, and to provide protection to the plants

against resident pathogen populations.

PGPR affect plant growth in two ways, directly and indirectly. The direct promotion of plant

growth by PGPR entails providing the plant with a compound that is synthesized by the bacterium

or facilitating the uptake of certain nutrients from the soil. The indirect promotion of plant growth

occurs when PGPR lessen or prevent the deleterious effects of one or more phytopathogenic

organisms.

Research on plant growth promoting rhizobacteria (PGPR) over the last three decades has

unraveled their efficacy in improving plant growth by increasing seed emergence, plant height,

weight and ultimately crop yield (Kloepper et al., 1980, 1986). Among PGPRs, most common are

Acenatobacter, Azotobacter, Bacillus spp., fluorescent Pseudomonas spp., Rhizobium spp., etc.

During last decade much of the research, however, has focused on organisms belonging to

Pseudomonas and Bacillus species. These organisms have shown great antagonistic activity

against several soilborne pathogens of economically important crops (de Boer et al., 1999;

Fernando et al., 2004; Savchuk and Fernando, 2004; Negi et al., 2005).

In these organisms biocontrol activity is mediated through the production of antibiotics and

lytic enzymes, as well as through competitive exclusion (Duffy and Defago, 1999; Schnider-Keel et

al., 2000). The global regulatory two component system, GacS/ GacA is known to positively

control secondary metabolite production whih includes phenazine, pyrolnitrin, 2,4-

diacetylephlorogucinol, pyoluteorin, HCN, exoprotiases and chitinases (Chancey et al., 1999; Duffy

and Defago, 2000).

Diverse populations of PGPRs have been reported to play a major role in plant growth

promotion and suppression of root diseases, and are the subject of on going investigations

worldwide (Keel et al., 1996; McSpadden et al., 2000, Picard et al., 2000). Generally, diverse

populations of PGPRs provide better resource for the improvement of plant growth promotion and


- 189 -

biocontrol ability, as different strains possess varied modes of action and survival in diverse

environmental conditions (Ramesh et al., 2002; Stutz et al., 1986). Equipped with beneficial

activities, use of these bacteria is being promoted as a viable alternative to chemical measures, to

increase yield and manage diseases in agriculture crops. In response to environment and health

concerns about the extended use of pesticides, there is increasing interest in finding such effective

alternative approaches for plant growth promotion and management of crop diseases. The

biocontrol strains of PGPRs have different molecules and mechanisms to encounter

pytopathogens. A few are discussed below.

Siderophore production

Iron, one of the most abundant minerals on earth, is an essential requirement for almost all

organisms including microbes. To date, the only known exception is lactobacilli, which are devoid

of heam proteins, and hence have no iron requirement. However, iron in the soil is unavailable for

direct assimilation by microbes because of its unavailable form i. e., ferric iron or Fe3+, which is

prominent in the soil and sparingly soluble about 10-18 M at pH 7.4. This amount of soluble iron is

too low to support microbial growth in soil, which generally needs concentrations approaching 10-6

M for normal growth. Consequently to survive in such environments, organisms secrete iron-

binding legends (siderophores), which can bind the ferric iron and make it available to the host

microbe. These compounds have been identified as “low molecular weight, ferric specific legends,

the biosynthesis of which is carefully regulated by iron and the function of which is to supply iron to

the cell”.

Siderophore secreted by Pseudomonas spp. have been shown to have a very high affinity

for iron and bind most of the Fe3+ that is available in the rhizosphere, and prevent the pathogens

present in immediate vicinity from proliferation because of lack of iron. Similarly, siderophore-

mediated inhibition of Pythium ultimum, Pyricularia oryzae, Rhizoctonia solani and Xanthomonas

oryzae has been reported by Seong and Shin (1996) using P. fluorescens ps88.

HCN production

Cyanide production by rhizospheric pseudomonads has been reported to have a

detrimental effect on plant establishment in some crops, but on the other hand, is beneficial in

others being suppressive to root pathogens (Defago et al., 1990). HCN production by

Pseudomonas spp. has been suspected to be involved in the inhibition of potato rot development,

root rot of forage legume caused by P. ultimum and R. solani, Sclerotinia wilt of sunflower.

Production of antibiotics and antifungal metabolites

Secretion of various secondary metabolites by Pseudomonas spp. has been well studied,

and found to be inhibitory against different phytopathogens including soil borne fungal pathogens

(Weller, 1988). Inhibition of fungal pathogens in the plant rhizosphere was also achieved by

Pseudomonas spp. equipped with abilities to produce HCN, catalase and siderophore (Table 1).

Antibiotic production by fluorescent Pseudomonas spp. is considered as an important

factor in the disease suppression ability of the organism. The diversity in the type of antibiotics


- 190 -

produced by different strains is only now being fully recognized. Antibiotics such as phenazine,

pyoluteorin, pyrrolnitrin, tropolone, and 2,4-diacetyl phloroglucinol have been isolated from soil

fluorescent pseudomonads. Moreover, DAPG producing fluorescent Pseudomonas spp. were

shown to be highly enriched in take-all suppressive soils.

The production of AFMs in Pseudomonas is subject to complex regulation. Key factors in

the regulation of the biosynthesis of most AFMs are global regulation and quorum sensing. Global

regulation is directed by the gacS/gacA genes, which encode a two-component regulatory system

that senses an as yet unknown signal(s). Quorum sensing involves the production of N-acyl

homoserine lactone (AHL) signal molecules by an AHL synthase such as LuxI. At a threshold

concentration of AHL, which is reached only when a certain density of bacterial cells is present,

the AHL will sufficiently bind to and activate a transcriptional regulator, such as LuxR. The

activated form of the transcriptional regulator then stimulates gene expression.

Table 1: Some of the well-reported fluorescent Pseudomonas spp. and antifungal compounds

produced by them to exhibit biocontrol against various phytopathogen.

Bacterial strain

Origin Antifungal compound produced

Plants in studies

P. fluorescens F113

sugar beet rhizosphere 2,4-diacetylphloroglucinol (DAPG), siderophore, hydrogen cyanide (HCN)

Pea, Sugar beat

P. fluorescens CHAO

Soil suppressive to black root rot of Tobacco

DAPG, pyoluteorin (plt), hydrogen cyanide

Wheat, Pea Cucumber

P. fluorescens DR54

sugar beet rhizosphere Viscosinamide, cellolytic enzymes

Barley

P. fluorescens Q2-87

Wheat rhizosphere DAPG Pea

P. fluorescens Q8r1-96

Wheat rhizosphere DAPG Wheat

P. fluorescens Pf-173

Mustured rhizpsphere Siderophore, catalase, HCN and antibiotics (to be identified)

Wheat, Pea, French bean, Ragi

Spontaneous gacS or gacA mutants of P. fluorescens strain CHA0 have a substantial

selective advantage over the wild-type strain when growing in a liquid medium (as has been

demonstrated in a nutrient broth medium that contained yeast extract). This can present a severe

problem to the production of inoculants. This difficulty can be reduced, however, by mineral

amendments or by simply diluting the medium (Duffy and Defago, 1999).

Genetic Diversity among PGPRs

Generally, greater diversity of introduced bacterial inoculants results in a diverse but

potentially more stable rhizosphere community to colonize the root system and survive against

biological, physical and chemical changes occurring in rhizosphere throughout the plant growth.

These changes are very likely to occur in rhizosphere of host plant in all growing seasons.

Further, diverse populations of PGPRs increase the spectrum of action, as different strains


- 191 -

possess different modes of action. Therefore, it is quite reasonable to assume that performance of

the isolates of the same genotype will be more or less same depending upon the environment

provided during characterization. Nevertheless, genetic characterization tends to be necessary to

render provide a clearer picture. Different techniques have been employed to assess the genetic

diversity among different rhizobacterial PGPRs including biochemical, immunological and

molecular tools. A number of PCR based techniques have been devised and are strengthened

over last decay. These include RAPD-PCR, BOX and ERIC PCR, Rep PCR etc., which have

been used extensively to assess the genetic diversity among PGPRs. Higher diversity level

among the pseudomonads was also reported by Raaijmakers and Weller (2001) and Ramesh

Kumar et al. (2002) Specific groups could be identified using different molecular tools including

RAPD-PCR. Mavrodi et al. (2001) estimated genetic diversity among 123 P. fluorescens using

RAPD-PCR, BOX-PCR and correlated identification of 2, 4-DAPG producing strains on the basis

of phlD gene by RFLP analysis. Similarly, McSpadden Gardener et al. (2000) developed a rapid

and reliable PCR based assay for rapid characterization of 2, 4-DAPG producing Pseudomonas

population based on the amplification of phlD gene sequence. Recently, Negi (2006) has shown a

tremendous diversity in rhizospheric Pseudomonas population isolated from Uttarakhand hills

using RAPD PCR. In this study RAPD-PCR profile could group the different pseudomonads in

different lineages on the basis of their host of origin and habitat. The study remarks first large

scale characterization of Pseudomonas spp. from Uttarakhand hills.

Future Prospects

As our understanding of the complex environment of the rhizosphere, of the mechanisms

of action of PGPR, and of the practical aspects of inoculant formulation and delivery increases, we

can expect to see new PGPR products becoming available. The success of these products will

depend on our ability to manage the rhizosphere to enhance survival and competitiveness of these

beneficial microorganisms. Rhizosphere management will require consideration of soil and crop

cultural practices as well as inoculant formulation and delivery. Genetic enhancement of PGPR

strains to enhance colonization and effectiveness may involve addition of one or more traits

associated with plant growth promotion. The use of multi-strain inocula of PGPR with known

functions is of interest as these formulations may increase consistency in the field. They offer the

potential to address multiple modes of action, multiple pathogens, and temporal or spatial

variability.

REFERENCES

1. Chancey, S. T., Wood, D. W. and Pierson, L. S. 1999. Two component transcriptional regulation of N-acetyl-homoserine lactone production in Pseudomonas aureofaciens. Appl. Envin. Microbiol. 65: 2294-2299.

2. de boer, M., van der Sluis, I. van Loon, L. C. and Bakker P. A. H. M. 1999. Combining fluorescent Pseudomonas spp. strains to enhance suppression of Fusarium wilt of radish. European J. Pl. Pathol. 105: 201-210.


- 192 -

3. Duffy, B. K. and Defago, G. 1999. Environmental factors modulating antibiotic and siderophore biosynthesis by Pseudomonas fluorescens biocontrol strain. Appl. Environ.

Microbiol. 65: 2429-2438.

4. Duffy, B. K. and Defago, G. 2000. Controlling instability of gacS-gacA regulatory genes during inoculant production of Pseudomonas fluorescens biocontrol strains. App. Environ. Micorobiol. 66:3142-3150.

5. Fernando, W. G. D., Nakkeeran, S. and Zhang, Y. 2004. Ecofriendly methods in combating Sclerotinia sclerotiorum (Lib.) De Berry. Recent Res. Devel. Envion. Biol. 339-347.

6. Kloepper, J. W., Scher, F. M., Laliberti, M. and Tipping, B. 1986. Emergence promoting bacteria: Description and implication for agriculture. In: Iron Siderophore and Plant Disease.

Swinburne, T. R. (Ed). Planum, New York. pp 155-164.

7. Kloepper, J. W., Schroth, M. N. and Miller, T. D. 1980. Effects of rhizosphere colonization by plant growth promoting rhizobacteria on potato development and yield. Phytopathol.

70:1078-1082.

8. Mavrodi, Olga. V., Gardener, B. B. M., Mavrodi, D. V., Bonsal, R. F., Weller, D. M. and Linda, S. T. 2001. Genetic diversity of phlD from 2,4-diacetylphloroglucinol-producing fluorescent Pseudomonas spp. Phytopathol. 91: 35-43.

9. McSpadden Gardener, B. B., Mavrodi, D. V., Linda S. T. and Weller, D. M. 2000. A rapid polymerase chain reaction-based assay characterizing rhizosphere population of 2,4-diacetylphloroglucinol producing bacteria. Phytopathol. 91: 44-54.

10. Negi, Y. K., Garg, S. K. and Kumar, J. 2005. Cold-tolerant fluorescent Pseudomonas isolates from Garhwal Himalayas as biocontrol agents against root rot disease in off-season pea. Curr Sci 89:2151-2156.

11. Negi, Y. K. 2006. Strain improvement of fluorescent Pseudomonas spp. with respect to their PGPR activities using molecular approaches. Ph. D. thesis submitted to Dr. R. M. L. Avadh University, Faizabad U. P. (India).

12. Picard C, Di Cello, Ventura M F et al (2000). Frequency and diversity of 2,4-diacetylploroglucinol-producing bacteria isolated from maize rhizosphere at different stages of plant growth. Appl Environ Microbiol 66:948-955.

13. Raaijmakers, J. M. and Weller, D. M. 2001: Exploiting genotypic diversity of 2,4-diacetylphloroglucinol-producing Pseudomonas spp.: characterization of superior root colonizing P. fluorescence strain Q8rl-96. Appl. Environ. Microbiol. 67: 2545-

2554.

14. Savchuk, S. and Fernando, W. C. D. 2004. Effect of timing of application and population dynamics on the degree of biological control of Sclerotinia sclerotiorum by bacterial

antagonoists. FEMS Microbiol Ecol. 49:379-388.

15. Schnider-Keel, U., Seematter, A., Maurhofer, M., Blumer, C. Duffer, B., Gigot-Bonnefoy, C., Reimmann, C., Notz, R., Defago, G., Hass, D., and Keel, C. 2000. Autoinduction of 2,$-diacetylphloroglucinol biosynthesis in the biocontrol agent Pseudomonas fluorescens CHA0 and repression by the bacterial metabolites salicylate and

pyoluteorin. J. Bacteriol. 182: 1215-1225.

16. Seong, Ki-Young and Shin, P. G. 1996. Effect of siderophore on biological control of plant pathogens and promotion of plant growth by Pseudomonas fluorescens ps88. Agric. Chem. Biotechnol. 39: 20-24.

17. Weller, D. M. 1988. Biological control of soil borne plant pathogens in the rhizosphere with bacteria. Ann Rev Phytopathol 26:379-407.


- 193 -

0

10

20

30

40

50

60

70

80

90

100

Incid

en

ce (

%)

1987-

96

1996-

97

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Leaf Fruit

Recent Advancement in the Management of Apple Scab

K.P. Singh and J. Kumar College of Forestry & Hill Agriculture, GBPUA&T, Hill Campus, Ranichauri-249 199

Amongst various disease attacking apple trees, scab incited by a fungus Venturia

inaequalis (Cke.) Wint. is economically important in apple production areas in India The first out-

breaks were reported in 1973 in the Kashmir valley. In 1983, the disease was affected resulting in

severe epiphytotic in Himachal Pradesh. Subsequently, it has been reported from Uttarakhand

(1987) in few localized pockets. The disease spread was so quick that the entire apple growing

area of the state was affected resulting in severe epiphytotic in 1996. Epidemics may be severe,

and depending on the year and apple growing area, state losses may be between 1 and 13

percent of total production, inspite of the control measures applied. Levels of disease (16 to 35 %)

one year may be followed by up to 96 percent infected leaves/ fruit in the next year (2008). It

occurred in epidemic proportion in 1996 and 2008 in the Gangotri valley (Uttarakashi) of

Uttarakhand resulting in a loss of up to Rs. 1. 25 crores and 68 lakhs, respectively. In 1996, the

government had taken decision to purchased scab infected apples @ Rs. 2.00/ kg and destroyed

on the spot. In 2008, scab has made nearly 23 per cent of the apple crop unfit for either market

consumption or processing.

The total loss due to scab disease is

more as compared to any other disease. Its

major effect is on the foliage as well as on the

yield and quality of fruit. The disease makes

the trees weak by mid season because of

defoliation and subsequently unproductive.

The fruit size is reduced, it gets disfigured,

deformed, scabby, knotted, poor market value

and storage capacity.

The intensity of apple scab can be

substantially reduced by timely application of fungicides that are either protective, curative or have

eradicant action against the pathogen. These sprays are recommended at various susceptible

phonological stages of apple trees. A protective spray programme being adopted in apple

orchards in India includes 7 to 8 spray of non-systemic and systemic fungicides during the growing

season and a single application of urea in autumn. Obviously, protective sprays of Thiophanate

methyl methyl + mancozeb, Hexaconazole, Flusilazole, Penconazole, Carbendazim and Captan

from pink bud through pre-harvest stage at 25 days interval effectively control the most of the

foliage diseases in high altitude area of Gangotri fruit belt. The first spray of thiophanate methyl +

mancozeb and 2nd spray of Hexaconazole or carbendazim were more effective in the suppression

of symptoms development and sporulation of ascospore. The contact fungicides captan, benomyl,


- 194 -

0

2

4

6

8

10

12

14Harsil

Sukhi

Auli

Joshimath

Syori

Koti

Talwadi

Gwaldam

288 308 328 348 3 23 43 63 83 103 123 143 164

Day of Year

Pseudothecial

initiation

Pseudothecia with

Pseudoparaphyses

Mature pseudothecia

with Asci formation

Asci with colored

ascospores

mancozeb, metiram, and maneb are often tank mixed with EBI fungicides to increase the disease

control of spectrum and to improve control of fruit scab Sterol inhibiting fungicides viz.,

hexaconazole, fenarimol, myclobutanil, bitertanol, flusilazole and penconazole showed excellent

after-infection, pre-symptom (curative) and post-symptom (eradicative) activities against the scab

pathogen and were also utilized in eradicant spray programmes successfully. Our approach is to

suggest that apple production can not be done profitably without fungicides whose judicious and

timely use in suitable spray schedules has obvious benefits in reducing environmental pollution

and substantial benefits to the apple growers. Public demands to reduce pesticides in our food

chain should lead to increased support for research to find alternatives. A number of profound

changes in Western society point to greater support for disease prediction research and greater

acceptance of forecasting based control strategy.

Installing an apple scab forecasting and monitoring system at Harsil, Purola-Naugaon, Koti-

Kanasar, Gwaldam and Joshimath

and recorded weather parameters.

A model to predict ascospore

maturity for use in Uttarakhand

orchards. These model are

designed to identify earliest date

of ascospores are matured

and discharged. In Garhwal

Himalayas, scabbed infected

apple leaves from unsprayed

orchards of Red Delicious cultivars

were collected periodically between 1st week of March to June each year from 1995 to 2008.

Development of pseudothecia and their maturation at the eight sites in Uttarakhand is illustrated in

Figure, which depicts the proportion of pseudothecia at each developmental stage from October to

June.

In orchard, the primary source of

inoculum overwintered on infected leaves

which could provide ascospores throughout

the growing season, foliar fungicides alone

may not give satisfactory control of the

disease. Five per cent urea and hundred per

cent cow urine spray not only suppressed the

ascospore production completely in the fallen

apple leaves but also helped in the early

decomposition of the leaves by increasing the

microbial activity of fallen leaves, while no

0

3000

6000

9000

12000

15000

18000

Asc

os

po

re d

isc

ha

rge

d /

cm

2

Co

w U

rine

Urin

e +

Wa

ter

Co

w d

un

g

Ure

a

Ure

a

Bo

rde

au

x m

ixtu

re

Co

pp

er

ox

yc

hlo

ride

Co

pp

er

hy

dro

ox

cid

e

Carb

en

da

zim

+

Ma

nc

oze

b

Co

ntro

l

Harsil

Auli

Syori

Koti-Kanasar

Tal-Talwari

Joshimath


- 195 -

such apparent effect on leaves treated with Bordeaux mixture, copper and carbendazim plus

mancozeb were observed through these were some equally effective in suppressing ascospore

discharge

The ascospore maturity started around 2nd week of March and continued upto last week of

May at different place of Uttarakhand Himalayas. On examination of the primary infection period of

15 years data from Gangotri fruit belt, some differences were observed between our results and

Mills table developed by Mills (1944) and Mills and La Plante (1951) for ascospores infection.

Figure shows 5 to 8 light infection periods occurred during each year in the month of March, April

and May which could initiate the primary

infection and time required for symptom

expression was 9 to 14 days under

prevailing temperature condition.

Whichever the infection time was more than

precticted (1 to 4 days) as mentioned in

Mills table. Four to ten moderate infection

periods were recorded in each month

during 1990-2008 and almost all indicated

delay by a day in symptom expiration (1-3 days) in orchard conditions. The third criteria as

described by Mills was severe infection period, 2 to 5 infection periods were observed in most of

the month at an average temperature (11.4 to 15.2 ºC) and leaf wetness (23.4 to 27.2 hr) period

and indicated 1 to 2 days delay in symptom expression. This observation revealed 2 day (light

infection), 1 day (moderate infection) and 1 day (severe infection) delay in symptom expression

under orchard conditions. The regression analysis was used to describe relationship between Mills

infection criteria and our light, moderate and severe infection period data of Uttarakhand for

symptom appearance. In all the cases, the total variation was high in low moderate and severe,

infection curves. The prevailing microclimatic conditions, topography and apple cultivars might be

the possible reasons for the delay of ascospore release and symptom development in Uttarakhand

Himalayas.

Ascospore maturation data of ten consecutive years were pooled and plotted against

Celsius degree day accumulation from the date of first ascospore discharge of Garhwal hills.

Based on the results, two linear lines were developed, one for the use when the cumulative degree

days from 1 February to 15 May was < 657 and another for use when the cumulative degree-days

for these dates was > 657. Our results showed that 50 and 95 per cent ascospores matured after

418 and 792 cumulative degree days, respectively for the orchards situated at 1900-2200 m asl

(villages Auli, Syori, Koti-kanasar, Talwadi and Gwaldam) while for orchards situated at higher

elevation (i.e. > 2200 m; e.g. villages Harsil, Dharali, Jhalla, Sukhi and Auli) the cumulative

degree-days was > 1182 (95% ascospore maturity). The duration of ascospore discharge in the

field appeared to be longer and varied from place to place.

y = -0.0094x + 12.069

R2 = 0.0177

y = -0.0104x + 14.549

R2 = 0.0195

0

5

10

15

20

25

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

LW

(h

r)/

Av.

Tem

p.(

0C

)/M

ills

In

fecti

on

days/

Sym

pto

m a

pp

eare

d (

days)/

D I

(%

)

leaf wetTemp.MillsSymptomIncidenceLinear (Mills)Linear (Symptom)


- 196 -

The PAD for each orchard was the product of the lesion density (number of lesions on

leaves per square meter of orchard floor at leaf fall), leaf litter density (proportion of the orchard

floor covered by leaf litter at bud break), pseudothecial density (number of mature pseudothecia

per visible lesion multiplied by a lesion fertility factor), ascus density (number of asci per

pseudothecium) and number of ascospores per ascus. To evaluate PAD, estimation of scab

lesion on leaves per m2 of orchard floor at leaf fall was done during October 2001 to 2007 at

Gangotri valley (Bhatwari fruit belt). The leaf litter density (LLD) was observed in 2002 to 2008 at

each of the four experimental sites at bud-break stage of apple. The number of mature

ascospores per visible lesion was computed as the product of lesion fertility and the number of

mature pseudothecia per fertile lesion. Ascospore density was the product of the number of

ascospores per ascus and the proportions of asci with mature ascospores per pseudothecium.

The latter was set to 137 asci per ascocarp with a standard error of 9.2. The ascospore

productivity per fertile lesion was the product of pseudothecia per fertile lesion (26.3) x asci per

pseudothecium (137) x ascospores per ascus (8). The PAD were calculated in different orchards

of Integrated managed (Urea/ bio-control agents spray at leaf fall stage, warning services, Sprays

of EBI fungicides), well-managed (cultural practices, warning services, Sprays of EBI fungicides),

moderately managed (bio-control agents spray at leaf fall stage, cultural practices, warning

services, sprays of organic fungicides {Copper, Flowable Sulfur, Sulphur, Lime-Sulfur} at different

phonological stage of tree) and poorly managed (Without sprays and cultural practices) groups.

On this basis, the scab incidence was classified as small, medium and high in Integrated

managed, well managed, moderately managed, and poorly managed orchards, respectively.

Vaseline coated slides ware placed in the managed and poorly managed orchards and

were positioned two cm above over wintered leaves on the orchard ground. The numbers of

spores collected on a slide were used to determine the progress of seasonal patterns of ascospore

maturation for formulating scab warnings.

Seasonal variation in ascospore discharge is given in following Figures. Only 2 to 28 per

cent of the total discharge was observed

during most of the meteorological weeks,

while the weeks 23 had 37 and 68 per

cent ascospore discharge in poorly

managed orchard, respectively. The

ascospore discharge were severe in the

week 23, moderate in 22 and 24 and low

in early instances in all the years. These

results were correlated with weather

parameters, viz., leaf wetness and

infection period, and were much helpful in the release of scab warnings and issuing control

recommendations.

0

10

20

30

40

50

60

70

Cu

mm

ula

tiv

e p

erc

en

t tr

ap

pe

d a

sc

os

po

res

17 18 19 20 21 22 23 24 25 26

Meterological weeks

PM

IM

WM

MM


- 197 -

Leaf litter density values were generally equal (30-46%) in IM, WM, MM and PM orchards

at most of the experimental sites. Lesion density ranged between 1 to 3.5 lesions/m2 orchard floor

in IM orchards and 29 to 39.5 lesion/m2 orchard floor in PM orchards at the end of October during

2004, 2005 and 2006. Lesion density was generally low in IM orchards and very high in PM

orchards, and showed significant differences. The ascospores production per m2 orchard floor

was the lowest in IM orchards (1672-2124) and was much higher (27957-61430) in PM orchards

during all the three years.

PAD assessments are not time consuming for a trained person, but the method could be made

simpler to be followed by the grower.

According to earlier studies, the PAD

values varied between 0 to 1,505,027

ascospores/m2 orchard floor, which were

dependent upon plant protection measures

undertaken during previous years. In our

study, PAD values were low during 2004-

2006 in IM orchards at Harsil fruit belt

when compared to PM fruit belt for the

reason that the crop was properly

managed by Urea/ bio-control agents and

EBI fungicides (Flusilazole) on different phonological stage of apple. In IM orchards, last fungicide

spray was given 15 days before harvest and 5 per cent urea/ antagonist spraying were given at

leaf fall, which could be the reasons for the low PAD values, in spite of weather conditions being

favorable. In Ganthori valley, we observed different PAD levels in IM orchards and thus reduced

sprayings were effective [Figure 22]. During the years 2004-2006, several infection periods were

recorded before and after petal fall stage

of tree but spraying were left out. In

orchards with low inoculum levels, no

scab was observed.

PAD values were 50 times higher

in the PM orchards than in the IM orchards.

In the study area, Gram Panchayat

orchards were found to be poorly

managed, University adopted farmer’s

orchard as Integrated and well managed

orchards and Govt. orchards as

moderately managed, where some of the orchard management practices were adopted. However, IM

orchards were well managed during years of the study. Our result showed that on the basis of PAD

the epidemic risk was low to medium in the IM orchards, while it was very high in the PM orchards.

-10

0

10

20

30

40

50

60

70

IM WM MM PM IM WM MM PM IM WM MM PM

2004 2005 2006

Lesio

n d

en

sit

y/

LL

D/

Perc

en

t sh

oo

ts a

nd

fru

its w

ith

scab

-10000

0

10000

20000

30000

40000

50000

60000

70000

Po

ten

tial

asco

sp

ore

do

se

lesion/m2

Leaf litter density (%)

percent shoots with scab

percent fruits with scab

PAD


- 198 -

The results of this study thus suggest that the reduction of primary inoculum sources could

have a decisive role in the management of apple scab. There is a risk of early scab epidemics

initiated by over wintering inoculum in the orchards where there had been a high scab incidence in

the previous seasons. While, the risk might be negligible in well-managed orchards receiving

integrated management practices in the preceding growing seasons. The number of chemical

applications will vary with the frequency of PAD. Good scab management could be obtained by

giving no more than 3-4 fungicide applications and 5 per cent urea spray at the time of leaf fall, if it

were backed by estimation of degree-days for ascospore discharge and potential ascospore dose

during early stage of growing season, even though numerous infection periods were observed

during post infection period.

Inspite of much advancement in the development and computation of mathematical models

or predictive equations, and automatic monitoring of weather data for apple scab, majority of the

orchardists in USA, UK and several other countries still rely on initiating the first spray at silver tip

to ¼ “ green tip stage in spring, and following a 7-10 day spray schedule thereafter till the primary

scab season is over.


- 199 -

Soil Solarization: An Effective and Ecofriendly Disease Management Strategy

Y. Singh

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263145 (Uttarakhand)

Several methods have been developed for the management of diseases incited by various

plant pathogens, which include fungicidal application, breeding for disease resistance, sanitation,

crop rotation, biological control and soil disinfestations. The need for different methods of plant

disease management stems from the fact that usually none of them is perfect nor can any one be

used under all circumstances. Moreover, the life cycles of pathogens may vary in different crop

systems, thus requiring different management strategies. Therefore, any new method of disease

management is of value since it adds to our rather limited arsenal of control methods. This is

particularly true with novel non chemical approaches which are needed to replace hazardous

chemicals.

The concept of managing soil borne pathogens has now changed. In past, control of these

pathogens concentrated on eradication. Later it has been realized that effective control could be

achieved by interrupting the disease cycle, plant resistance or the microbial balance leading to

disease reduction below the economic injury level, rather than absolute control. The integrated

pest management concept encompasses many elements. In this context soil solarization can play

a significant role.

In Israel, extension workers and growers suggested that the intensive heating that occurs

in mulched soil might be used for disease control. By mulching the soil with transparent

polyethylene sheets in the hot season prior to planting, a team of Israeli workers developed a solar

heating approach for soil disinfestation (Katan, 1995). Soil solarization is a method of controlling

soil borne pests and pathogens by raising the temperature of the soil through application of

transparent polyethylene sheet to a moist soil surface. With solarization vast possibilities for

disease control are possible. Use of this method has been reported to reduce the population of

many soil borne pathogens including fungi bacteria and nematodes as well as weeds (Pullman et

al.,1981; Katan et al., 1983; Barbercheck et al; 1986; Verma et al; 2005).

Mechanism of disease control

Reduction in disease incidence occurring in solarized soils, results from the effects exerted

on each of the three living components involved in disease (host, pathogen, and soil microbiota)

as well as the physical and chemical environment which, in turn affects the activity and

interrelationships of the organisms. Although these processes occur primarily during solarization,

they may continue to various extents and in different ways, after the removal of the polyethylene

sheets and planting. The most pronounced effect of soil mulching with polyethylene is a physical

one, i.e. an increase in soil temperatures, for several hours of the day. However, other

accompanying processes such as shifts in microbial populations, changes in chemical composition


- 200 -

and physical structure of the soil, high moisture levels maintained by the mulch, and changes in

gas composition of the soil, should also be considered while analyzing mechanisms of disease

control. The following equation proposed by Baker (1968), for relating the various factors involved in

biological control, should be adopted for this analysis:

Disease severity =inoculum potential x disease potential, where inoculum potential is the energy

available for colonization of a substrate (infection court) at the surface and disease potential is the ability

of the host to contract disease. More specifically the equation becomes:

Disease severity = (inoculum density x capacity) x (proneness x susceptibility), where

capacity is the effect of the environment on energy for colonization, and proneness is the effect of

the environment on the host. Of these four components, inoculum density (ID) is the one most

affected by solarization either through the direct physical effect of the heat or by microbial

processes induced in the soil. The other components, however (except for susceptibility which is

genetically determined) might also be affected. Microbial processes, induced in the soil by

solarization, may contribute to disease control, since the impact of any lethal agent in the soil

extend beyond the target organisms. If induced by solarization, biological control may affect the

pathogen by increasing its vulnerability to soil microorganisms or increasing the activity of soil

microorganisms toward pathogen or plant, which will finally lead to a reduction in disease

incidence, pathogen survivability, or both. Thus both short and long term effects might be

expected. Biological control may operate at any stage of of pathogen survival or disease

development during or after solarization, through antibiosis, lysis, parasitism, or competition. The

mechanisms of biological control, which may be created or stimulated by solarization are

summarized as follows:

I. The effect on the inoculum existing in the soil.

A. Reduction in ID (in the dormant stage or during host penetration) through

1. microbial killing of the pathogen, already weakened by sublethal heat;

2. partial or complete annulment of fungistasis and subsequent lysis of the

germinating propagule;

3. parasitism or lysis by antagonists stimulated by solarization.

B. Reduced inoculum potential (IP) due to competition or antibiosis induced by

solarization.

C. Diminished competitive saprophytic ability of the pathogen, in the absence of the

host, due to antibiosis or competition.

II. Preventing reinfestation through activities of microorganisms possessing mechanisms A2,

A3, B, and C

III. The effect on the host due to cross protection

Combining solarization with other methods such as pesticides or biocontrol agents

improves disease control. Whenever a pathogen is weakened by heating, even reduced dosages

might suffice for improved control combining with biocontrol agents, organic amendments, etc.


- 201 -

Advantages

Soil solarization as a disinfestations method, has potential advantages. It is a non chemical

method which is not hazardous to the user and does not involve substances toxic to the consumer, to

the host plant or to other organisms. In the right perspective it is less expensive than other methods.

This technology can easily be transmitted to the ordinary farmers and can be applied in large areas

manually and mechanically. Thus, it is suitable for both developed and developing countries. It may

have a long term effect, since effective disease control lasts for more than one season. This method

has the characteristics of an integrated control, since physical, chemical and biological mechanisms

are involved and because the control of a varieties of pests is achieved.

Limitations

Solarization involves limitations, difficulties and potential negative side effects. It can only be

used in regions where the climate is suitable (hot) and the soil is free of crops for about one month or

more at a time of tarping with PE sheets.

It is too expensive for some crops and ineffective in the control of certain diseases

Heat tolerant pathogens might develop after repeated application, though selection for

tolerance to lethal agents is not likely to develop with disinfestation methods which are not

target specific

Another possibility would be an increase in pathogen population due to a harmful effect on its

antagonists

Disease Management

Soil solarization has been demonstrated to control diseases caused by many fungal pathogens

such as Rhizoctonia solani, Fusarium spp., Pythium spp., Phytophthora spp., Verticillium spp.,

Sclerotium rolfsii etc. in many crops (Katan et al., 1983; Abdul et al., 1995; Raoof and Rao,1997). Soil

solarization has also been shown to significantly decrease the population of disease causing

Agrobacteria and Pseudomonas (Raio et al., 1997; Chellemi et al., 1994). Many nematode diseases

caused by Meloidogyne spp., Heterodera spp. etc.have been successfully controlled by soil

solarization (Rao and Krishnappa, 1995; Grinstein et al., 1995).

Beneficial side effects

Control of weeds

Solarization results in an effective weed control lasting in some cases for more than two or

three seasons (Abdel Rahim et al., 1988; Verma et al., 2005). In general most of the annual and many

perennial weeds have been found to be effectively controlled.

Increased growth response

The increased growth response of plants in solarized soil is a well documented phenomenon

and has been verified both in green house experiments and under field conditions (Katan, 1987; Chen

et al., 1991; Singh, 2008).

Conclusion


- 202 -

Soil solarization for soil disinfestations has been well established and demonstrated under

experimental or commercial conditions in a number of countries. The ultimate goal to develop this

method for use under field conditions requires both basic and practical studies. Although SS is a

simple method, the research involved for its establishment in new areas is complicated and requires

interdisciplinary efforts. SS should not be regarded as a universal method but rather as an additional

one which, if used correctly, can reduce pest damage safely, effectively and economically.

More than 100 years after the introduction of soil disinfestations and more than 50 years after

Sanford’s classical publication on biological control our hungry world is still crying out for new methods

for reducing crop losses caused by soil borne pathogens. We are always confronted with difficulties

such as the appearance of new physiological races and development of resistance to pesticides while

using conventional control methods. We are frustrated by the large gap between promising results in

the green houses and failures in the fields. Thus we have acquired modesty. We no longer aim to

achieve absolute control, but rather an economic reduction in disease level. It is only natural, that the

integrated control approach, which calls for adequately combining all available control methods, was

adopted by the plant pathologists the world over. Solarization is a new additional option to use and

include suitably in such IPM programs. Its scope and rate of dissemination in the future will depend on

our capacity to both weigh its pros and cons and use it effectively.

REFERENCES

1. Abdel Rahim, M. F., Satour, M. M., Mickail, K.Y. and El Eraki, S. A. (1988). Effectiveness of soil solarization in furrow irrigated Egyptian soils. Plant Dis.. 72: 143-146.

2. Barbercheck, M.E.and von Broembsen, S.L (1986). Effect of soil solarization on plant parasitic nematodes and Phytophthora cinnamomi in South Africa.Plant Dis. 70:945-950.

3. Chen, Y., Gamliel, A., Stapleton, J. J. and Aviad, T. (1991). Chemical, physical and microbial changes related to plant growth in disinfested soils. In: Soil Solarization. Katan, J. and De Vay, J. E. (eds.) CRC Press, Inc., Boca Raton, FL. pp. 103-129.

4. Katan, J. (1987). Soil solarization. In: Innovative approaches to plant diseases control. Chet, I. (ed.). John Wiley & Sons New York. pp 77-105.

5. Katan, J., Fishler, G. and Grinstein, A. (1983). Short and long term effects of soil solarization and crop sequence on Fusarium wilt and yield of cotton in Israel. Phytopathology. 73:1215-1219.

6. Pullman, G.S., Devay, J.E., Garber, R.H. and Weinhold, A.R. (1981) Soil solarization on Verticillium wilt of cotton and soil borne population of Verticillium dahliae, Pythium spp., Rhizoctonia solani and Thielaviopsis basicola. Phytopathology. 71:954-959.

7. Verma, R. K. Singh, Y., Soni, K. K. and Jamalluddin (2005). Solarization of forest nursery soil for elimination of root pathogens and weeds. Indian J. Trop. Biodiv. 13: 81-86.

8. Chellemi, D.O.., Olson, S.M. and Mitchell, D. J. (1994). Effect of soil solarization and fumigation on survival of soil borne pathogens of tomato in Northern Florida. Plant Dis. 78: 1167-1172.

9. Grinstein, A., Kritzman, G., Hetzroni, A., Gamliel, A. Mor, M. and Katan, J. (1995). The border effect of soil solarization. Crop Protect. 14: 315-320.


- 203 -

10. Katan, J. (1995). Soil Solarization- a non chemical tool in plant protection. Indian J. Mycol. .Pl. Pathol. 25: 46-47.

11. Raio, A., Zoina, A. and Moore, L. W. (1997). The effect of solar heating of soil on natural and inoculated agrobacteria. Plant Pathol. 46: 320-328.

12. Rao, V. K. and Krishnappa, K. (1995). Soil solarization for the control of soil borne pathogen complexes with special reference to M. incognita and F. oxysporum f.sp. ciceri. Indian Phytopath. 48: 300-303.

13. Raoof, M. A. and Nageshwar Rao, T. G. (1997). Effect of soil solarization on castor wilt. Indian J. Plant Protect. 25: 154-159.

14. Singh, Y. (2008). Effect of soil solarization and biocontrol agents on plant growth and management of anthracnose of sorghum. Internat. J. Agric. Sci. 4: 188-191.


- 204 -

Modeling Plant Disease Epidemics for Crop Protection

V.S. Pundhir Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar-263 145 (Uttarakhand)

The use of mathematical models in science is probably a search for underlying general

principles, so that they can be explained in language of numbers and used for quantitative

estimations. The models are important and integral part of science, whether physical or biological,

as they have become valuable tools applied for benefit of humanity. Model is not a miniature of

some real system. Models are simple representation of otherwise more complex real systems. The

models provide opportunity for better understanding and system management. Kranz, (1974)

stated that a model might be a verbal statement, a hypothesis, a theory or a law. Modeling in Plant

Pathology started with pioneering synthesis of Vanderplank (1963) and aerobiology of Gregory

(1961). Four types of models have been described in Plant Pathology.

Conceptual Models: The conceptual models were conceived during initial stages of introduction

of models in plant pathology. They were basically qualitative, without much quantification. The

relationships and interactions were displayed in diagrammatic form of flowchart manner. The

famous disease pyramid and components of pathogenesis or system approach are good

examples of conceptual models. These also included ‘hypothesis or statements’ about basic

features of disease development (gene for gene).

Analytical models: Vandenplank (1963) used differential equations for calculation of pathogen

population growth. Equations for single and multiple cycle diseases, threshold theorem and fitting

curves to empirical data are common analytical models used in plant pathology. Best choice is

always the simplest function that gives the best fit to the observed facts (data). Other analytical

models include biological control of cereal rust (1980, (1982), development of fungicide

insensitivity (1983), & fitness in plant pathogens.

Predictive Model: These are generally used for estimation of yields and forecasting diseases.

Regression and differential equations are generally employed. These are considered a boon to

growers for bringing precision in management decisions. Several models have established their

credibility e.g. PHYTOPROG in West Germany (Ullrich & Schrober, 1967) and BLITECAST in USA

(Krause et. al 1975) for warnings of potato late blight.

Simulation Models: These models try to ‘simulate’ or ‘mimic’ the real life situations under study.

Waggoner and Hossfall, in 1969, developed first simulator EPIDEM: Alternaria blight of potato and

tomato.

EPIMAY: southerncorn leaf blight of maize

EPIVEN: apple scab,

CERCOS: Cercospora blight of celery,

MYCOS: Mycospherella blight of chrysanthemum,

EPICORN: southern corn leaf blight of maize,

EPIVIT: for contact and aphid transmitted virsus of potato

EPIPRE: cerial rusts and aphids


- 205 -

Fry et al. (1983) modified and evaluated BLITECAST by incorporating host resistance and

fungicide weathering. EPIPRE (Zadoks, 1981 and 1984) is most successfully used in Europe for

management of cereal rusts and aphids. Gutierrez et. al. (1983) proposed cotton-Verticillium wilt

model that provides an example of coupling of crop and disease model. The model predicts cotton

yields (biomass) for different inoculum densities of pathogen V. dahliae.

Expert Systems in Plant Pathology

Expert systems (Es) are the frontiers, which combines and integrate both science of plant

pathology and art of diagnosis and disease management. Es are computer programs that emulate

the logic and problem solving proficiency of human expert. The computerized disease forecasting

systems of 1970s (BLITECAST) and apple scab forecaster in 1980s were the precursors to expert

systems. The Es are programmed to review a consultation and provide user with an explanation.

Three main areas involved in decision-making are pest risk estimation, current threat assessment

and pesticide selection. Future development of Es will require more interactive role of experts

(pathologists, entomologist, and computer programmers) and growers. Es provide site-specific

recommendations for judicious resource utilization for optimum production with least disruption of

environment. It will help to satisfy the IPM objectives.

Expert system being used in plant pathology

System Approach in Plant Pathology: Agriculture production requires the management of

biological systems, which involve plants, animals (the residues), soil microbes, insects and

pathogens. Agro-ecosystem is a complex system, which needs careful analysis and management

PLANT / ds: First Es developed (1983) for diagnosis of 17soybean diseases (USA)

POMME: Developed to manage diseases and insects on apples. First ES to incorporate decision-making process.

PSACO: Pennstate apple orchard consultant developed for 8 diseases, 17 insects. Es takes into consideration biological, chemical and cultural control options

POTATOES: Es for late and early blights of potato.

TOMEX: It uses 78 questions, 87 photographs, for diagnosis of 37 diseases of tomato

Grenmen: This is used for green house disease management

PRO – PLANT: ES for cereals also for potato sugar beat and vegetables

More Crop: Managerial options for reasonable economical control of rusts and other problems.

EPIPRE: “Epidemic Prediction and Prevention” (1992) spring and winter wheat.

ES for diagnosis of potato diseases, Boyd- W D; Sun M k (1994) EXSYS: ES for flower-bulb diseases, Kramers, M A et. al (1997) DESSAC: Integrated approach to DSS for Arable Crops, Brooks (1998) TomEx-UFV: ES for diagnosis of tomato diseases, Pozza et al. (1998) SIMPHYT III: ES for P. infestans, Gustscje et al. (1999) ES for cotton prosuction system, Bie-Shu et al. (2001)

DSS for precision agriculture, Chen. Li Ping et al. (2002)


- 206 -

of resources for optimization of sustainable farm income. A system is a set of components

coordinated to accomplish a set of goals. The system approach can be very conveniently applied

in areas crop health management. System analysis in plant pathology has emerged as a sub-

discipline of epidemiology where plant disease management is the goal to be achieved through

system approach.

Steps involved in System Approach: Churchman (1968) established five steps, which can also

be utilized for plant disease management.

(a) System objectives; this is initial but very vital step in system approach. The system objectives

and measures of performance are to be set by worker(s) before starting the task. The objectives

must be clearly defined; for example, control/ eradication/ management may be the ‘options’ to be

achieved. The objectives should be obtainable within limits of the system resources. The

management of disease at sub-economic level should be a reasonable long-term objective.

(b) System Design; It involves the detailed description of the problem, including the important

factors that influence the system or ultimate output i.e. the crop yield. The problem must be

described in logical and structured manner. The system design may desire the breakup of

complex system in to sub-systems, components or elements as per the need of the situation. It will

involve the study of relationships (cause-effects) among the factors influencing the system and

their quantification, if possible.

(c) System Model; the system model is the product of system analysis. Once developed, system

model is a good tool for experimentation for various presumed situations.

(d) System Evaluation; the evaluation of system model is done in accordance with the set

objectives and the measures of performance. The system evaluation has to be a continuous

process, where feedback based modifications are made. The best evaluation is the one performed

by the end user (the growers/ community) under their prevailing conditions.

(e) System Management; System model, after proper evaluation and validation, becomes a

useful tool for growers and further experimentation. It can be conveniently used for optimization of

the system for achieving the modified goals. Plant disease management program is the end

product of system analysis. Considering the frequently changing availability of resources and

technology for agriculture production system, the system analysis has to be an ongoing program.

Plant diseases are to be treated as a systems and not as a ‘social evil’.

REFERENCES

1. Campbell, C. L. and Madeen, L. V., 1990, Introduction to Plant Disease Epidemiology. Wiley, New York.

2. Chaube & Pundhir (2000) Crop Diseases & Their Management. Oxford- IBH Publication, New Delhi

3. Horsfall, J.G., and Cowling, E.B., (eds.), 1978, Plant Disease, vol. 2. Academic Press, New York.

4. Kranz, J. and Schein R.D., 1979, Epidemiology and Plant Disease Management. Oxford University Press, Oxford.

5. Kranz, J., 1974, Comparison of epidemics. Annu. Rev. Phytopathol, 12:355.


- 207 -

6. Krause, R.A., Massie. L.B., and Hyre, R.A., 1975, BLITECAST, a computerized forecast of potato late blight. Plant Dis. Rep., 59:

7. Leonard, K.M. and Fry, W.E., (eds.), 1986, Plant Disease Epidemiology, Volume 1: Population Dynamics and Management. Macmillan,

8. Lucas, J. A. 1998. Plant Pathology and Plant Pathogen. Blackwell Science,

9. Nilsson, H, E., 1995. Remote sensing and image analysis in plant pathology. Annu. Rev. Phytopathol, 33: 489.

10. Travis, J. W., and Latin, R.X. 1991, Development, implementation and adoption of expert systems in plant pathology. Annu. Rev. Phytopathol, 29:343.

11. Vanderplank, J.E., 1963, Plant Disease: Epidemics and Control. AP, NY.

12. Waggoner P. E., Horsfall, J. G. and Lukens R. J. 1972, EPIMAY, A simulator of southern corn leaf blight. Conn. Agric. Exp. Stn. New Havon, Bull., 729.

13. Zadoks, J. C. and Schein, R. D. 1979, “Epidemiology and Plant Disease Management.” Oxford University. Press, Oxford and NY.


- 208 -

Epidemiological Approaches to Disease Management through Seed Technology

Karuna Vishunavat

Department of Plant Pathology, GBPUA&T, Pantnagar- 263145(Uttarakhand)

Introduction

The quality of planted seeds has a critical influence on the ability of crops to become

established and to realize their full potential of yield and value. A complex technology is required to

ensure high standards of seed quality that involves-Producing, harvesting, processing, storing and

plating the seed.

Throughout this process, careful handling to avoid mechanical injury and protection from

adverse environmental conditions, pests, and diseases are imperative. No one factor is

necessarily more important than another with respect to maintenance of seed quality but almost all

seed crops require some measure of disease control. The knowledge of the epidemiology of seed

diseases can promote disease management through modern Seed technology.

Disease impact on seed management systems

Seed Pathology emerged as a sub-discipline of plant pathology from analysis of seed

quality in the early part of this century.

Since than a world wide process of cataloguing microflorae of seeds have been associated

approximately 2400 microorganisms with the seeds of 383 genera of plants. Concurrently

epidemiological studies were carried out on the seed-borne phase of economically important

diseases e.g. bacterial blight of beans, smuts of cereals and Stewart’s wilt of corn. There are three

environments in which seed exists:

A. The seed production field

B. Harvesting, processing and storing and

C. The planted field.

A. The seed production field

Disease can have an indirect effect on seed in the production field in that the seed is not

associated in any way with the pathogen but other plant parts are diseased; this renders the plant

physiologically ill equipped to complete the development and maturation of the seeds. Direct

effects means that the seed itself is diseased, thus the viability and appearance of the seed is

affected and /or the pathogen is transmitted to the plant grown from the seed.

(a). Seed infection in Seed production field

Seed infection can occur during the three distinct physiological phases in the seed

production field; anthesis, which covers the period from initiation of floral primordia to fertilization of

the embryo; seed development, which represents the period during which the fruiting structures

grow and develop to full physiological maturity; and seed maturation, which is the dry down period

that continues until the seed is harvested.


- 209 -

Each phase has unique characteristics with respect to the epidemiology and management

of seed disease.

(b). Management of seed borne diseases in seed production field

Elimination of Inoculum Sources

Disease management during anthesis

Disease management during seed development

Disease management during seed maturation

Elimination of inoculum, sources

The first opportunity for management of seed diseases is to eradicate or reduce pathogen

inoculum in the seed production field for e.g. Removal of crop residue (Phomopsis seed decay of

soybean). Removal of Infected weeds as perennial source of contamination (Brassica seed fields

by X. campestris pv. Campestris in Brassica ).Destruction of infested seeds, the primary source of

inoculum, by burning or by vacuuming fields (for ergot in perennial grass seed production fields).

Disease management during anthesis

The optimal time for Fusarium moliniforme infection of maize kernels by silk inoculation occurs

when silk begin to senesce. The infection process also may be influenced by environment. rain and

warm temperature following anthesis resulted in increased grain mold contamination of caryopses of

sorghum.Knowledge of the mechanism and enviornmental influences on infection at this growth stage

has been used to advantage in disease management. Several group of pathogens including smuts,

ergots, viruses, and nematodes infect seeds during anthesis.a unique feature of infection at this growth

stage is the facility for infection of embryos and other internal seed tissues. Embryo invasion by viruses

from the mother plant is dependent on short-lived cytoplasmic connections to the male or female

gametophytes. The potential for biological control during antesis was demonstrated by inoculation of

wheat florets with a stain of C. purpurea that did not biosynthesize ergot alkaloids, but had sufficient

parasitic vigor to displace alkaloid- producing strains.

Disease management during seed Development

Seed infection during seed development can occur by invasion through natural openings

including the funicle and micropyle, by direct penetration of the seed or caryopsis, or from pods or

freshy fruits. Infection also can be strongly influenced by environment. Osorio & McGee showed

that exposure of soybean pods to frost at --4.5 or -250c immediately before physiological maturity

predisposed seed to infection by Fusarium graminearum and Alternaria alternata but reduced seed

infection by Phomopsis longicolla .More over there are numerous reports of fungicide applications

in seed production field to control seed borne pathogens. But more strategically these studies are

rarely considered in disease epidemiology.The pod infection occurs at any time from flowering

onwards for number of seed borne pathogens e.g. in Phomopsis seed decay of soybeam ,

X.campestrisis pv. Vignicola but the fungus will not infect seeds until seed maturation begins. This

disease epidemiological aspect may be used as predictive methods of fungicidal application

.Cultural practices provide options to manage seed diseases in the production field; adjustment of


- 210 -

planting time , crop rotation , elimination of weed hosts , irrigation practices etc.Bean intercropped

with maize than on bean grown alone showed higher seed borne population of P.syringae pv.

phaseoliocola ( Mabagala and Saettler 1992).Biological control of seed infection during seed

development was demonstrated by the reduction of aflatoxin B1in the cotton seed after

simultaneous inoculation of wounded cotton ball with toxigenic and atoxigenic strains of

Aspergillus flavus.

Disease management during seed maturation

Certain fungi, such as Fusarium moniliformae in corn, Botrytis, Alternaria ,Cladosporium sp

commonly infest the soil and crop residues and may invade seed under prolonged periods wet

weather at seed maturation growth stage and cause seed discoloration and loss of viability.

Weathered seed experience physiological deterioration as well as pathological damages.

Effective control of disease during seed maturation is achieved by harvesting the seed as soon

as it is sufficiently dry.

Planting dates may be manipulated to avoid conditions favorable for seed infection as in

the case of Phomopsis seed decay of soybeans in which the chances of temperature and humidity

conditions favorable for seed infection occurring are much lower for late compared to early planted

crops ( McGee 1987) .There are few examples for breeding specifically for resistance to infection

of the seeds.e.g. a genotype resistance to Phomopsis seed decay and sources of resistance to

Cercospora kikuchii , the cause of purple seed stain of soybean have been identified( Brown et al

1987, Roy 1982) . Grain Hardness ,ergosterol content, and tennins have been implicated in

resistant to moulding of Sorghum grains ( Bosman et al., 1991).

B. Harvesting Conditioning and Storing

The harvesting process provides opportunities for pathogen structures , such as sclerotic ,

nematode soil peds, and teliospores to contaminate seed lots.

This type of contamination can be minimized by setting the harvesting equipment to avoid

contact with the siol and to eliminate physically altered seeds or pathogen structures. Seed when

passed over air screen cleaners and gravity separators help to reduce the fungal sclerotia or

infected seeds (Phomopsis infected seeds of soybean and plant debris).Paulsen 1990 used a

computer vision system to detect purple stained soybean seed infected with Cercospora kikuchii

with 91% accuracy.Walcott developed an ultrasound signal to detect asymptomatic infection of

Aspergillus and Penicillum spp. in storage in soybean.

1. Disease management during storage

Storage fungi ( Aspergillus and Penicillum sp.) invade grains and seed stored at moisture

contents in equilibrium with ambient relative humidity ranging from65-90% and can cause major

losses in seed viability.

Effective management of storage fungi invasion is obtained by drying of seeds below the

minimum moisture contents for storage fungi invasion and maintaining this moisture content by

aeration.

The effectiveness of this practice often breaks down, however, when seed is held in


- 211 -

storage facilities with poor environmental controls.

A few examples of management of storage fungi during seed storage are:

Soybean oil applied to reduce growth of storage fungi in maize and soybeans

(McGree1988).Insect and storage fungi management by mineral oil and soybean oil treatment in

beans ( Hall and Harman 1991)

The fungicides thiabendazole and Iprodione supress growth of storage fungi in stored corn

(White and Toman 1994).The potential for natural products

(Flabonoids and Isoflabonoids, and their derivatives ) to control storage fungi for seed of bean and

soybean is demonstrated by Weidenborner et al., 1990.

2. Seed Health testing

Seed health testing is used primarily to manage diseases by inoculum threshold, to

determine the potential effect of seed borne inoculum on stand establishment in the planted field,

and to meet the requirements for phytosanitary certification of seed lots to be exported. For seed

health testing following methods are routinely used:

Field inspection

It requires that the seed production field be examined for symptoms of a disease on growing

plants. The method is based on the assumption that incidence of infection on plants and seed

are related. Although there are few diseases where this relationship has been validated,

procedure remains the back bone of Phytosanitary certification in many countries.

Direct seed assay

Seed may be examined visually for clear signs or symptoms expressed on the seed

surface.Another approach is to soften seed tissues and then examine the internal tissues of the

seed microscopically for mycelium of the pathogen.

Incubation test:

It requires that the seed be subject to conditions that select for and optimizegrowth of target

pathogen. Assay usually require pretreatment with a chemical to surface disinfest the seeds,

followed by incubation on blotters or culture medium under precisely defined environmental

conditions.

Grow out test:

Seed are planted in the field or green house in the absence of other inoculum sources.

Seedlings are examined for symptoms produced by the seed borne pathogens. The procedure

requires much time, space, , and labour. It also tends to lack sensitivity, but it can predict well

the extent of seed transmission of Pathogens in the planted field.

Serological assays:

Serological assays for seed borne pathogens were first reported in 1965 with an agglutination

test for Pseudomonas phaseolicola in beans( Guthrie at al 1965)and double diffusion assay for

barley stripe mosaic virus ( Hamilton 1965).The introduction of ELISA to plant pathology in 1976

stimulated rapid advances in the use of serological assays for seed borne pathogens.With


- 212 -

diagnostic kits now available from the private sector for ELISA and its variants, serology has

become cost- effective and practical to detect seed borne pathogens through out the world .

However, a well known weakness in serological tests has been the propensity to detect false

positive caused by the binding of antibodies to epitopes, which may no longer be a propagule of

the pathogen which can be overcome by combining serological assay with a viability test.

DNA hybridization assay

DNA hybridization assay use a DNA probe that is complementary to DNA in the genome of

the plant pathogen.The probe is applied to a DNA extract from seed and hybrizied material

detected by dot blot hybridization assay. The technique has successfully used to detect

Peronosclerospora sorghi and P. sacchari in corn ( Yao et al 1990) Pseudomonas syringae pv.

Phaseolicola in bean seeds .

C. The planted field

1. Seedling emergence and establishment: There are sound epidemiological bases to establish

relationship between seed borne pathogens and seed quality and this impress upon the use of

seed treatment to improve seed vigor and reduce the seed borne inoculum for better plant

stand in field.

2. Transmission of seed borne pathogens: transmission of seed borne pathogens by following

factors:

a. Epidemiological factors affecting seed transmission:

Seed transmission for some seed borne pathogens is well defined. Few most promising

fungal pathogens such as Ustilago tritici, Neovossia indica,Telletia caries, Peronospora parasitica

in rape seed mustard, and many seed borne bacteria and viruses.

Physiological factors may affect the capacity of the seeds to transmit pathogens. Few

examples are:Downy mildew pathogen in maize can be transmitted when seeds are freshly

harvested, but not once the seeds are dried ( Mc Gee 1988.) Arabis mosaic nepovirus is

transmitted inefficiently in Nicotiana seed , because the virus reduce seed germination

Environmental factors play a major role in the efficiency of seed transmission of plant

pathogens.

The seed borne inoculum of Alternaria brassicae or A. brassicicola in rape seed mustard

reduces with the seed storage and at temperature above 35 0C the fungus is auto-eliminated in

tropical conditions. In Cabbage seedling disease caused by Alternaria brassicicola for e..g does

not occur below 150C in heavily infected seed lots .

b. Inoculum threshold

Inoculum threshold have been established on a sound epidimiological basis for only a few

pathogens, including Phoma lingum in Crucifers, Pseudomonas syringae pv. phaseologicola , and

lettuce mosaic virus. For many seed borne pathogens, inoculum threshold is determined either

arbitrarily or by field observation data ( Schaad 1988). To be of value, however the threshold

should be established in well designed experiments. The first step is to have a suitable seed


- 213 -

health assay. But very few methods are thoroughly researched to determine if they are specific,

accurate reproducible, and practical.

The next step is to plant seed with different infection level in the field and establish a

correlation with plant infection.

For diseases that have no repeating cycle of infection such as seedling infecting smuts,

strong correlation between seed infection and field diseases can usually be expected.

It is much more difficult to establish inoculum threshold for diseases for which secondary

infections occur from other inoculum sources.

c. Certification Programme

This programme exists to protect against spread of disease by seeds with in geographic

regions. In this programme seed lots must meet certain minimum standards of quality which

includes specific diseases, before seed can be marketed.

This programme uses knowledge of the epidiomiology of the disease that includes

laboratory assays of the seeds and field controls.

d. Phytosanitory certification

The system has some serous problems, however phytosanitary regulations are determined

by individual countries and often are made on the basis of a poor understanding of the economic

losses that introduction of particular pathogens could potentially incur; minimal knowledge of

relation ship between tolerances in seed assays to risks of transmission of the pathogen to the

planted crop; and lack of standardized testing protocols.

e. Germplasm

International Agriculture through out the worlds are taking steps to minimize the

introduction and spread of exotic seed borne pathogen by seed exchange.

Several international centers have implemented programs to manage seed borne pathogen

through monitoring pathogens in the seed lots, modification of seed production practices to

minimize the infection or transmission of pathogens by seed and use of seed treatment.

f. Seed treatment

Chemical, physical and biological seed treatment has dramatically changed in the last 20

years. As a result of new fungicide chemistry, advances in biological control and environmental

regulation that have either banned or restricted the use of fungicides. Fungicide seed treatment

remains the most widely used practice and established materials such as captan and thiram still

are the mainstay of seed treatment chemistry. Several systematic fungicides such as metalaxyl,

iprodione and triadimenol are being used for management of deep seated infections in seed and

subsequent protection of seedling against infection.

Chemical control of seed borne bacteria has limited success, either because of lack of

control of internal inoculum or phytotoxicicity to the seeds. Antibiotics, applied in polyethylene

glycol (PEG), reduced infection by Xanthomonas campestris pv. phaseoli in bean seeds, but were

phytotoxic.


- 214 -

Heat treatment, hot water treatment or microwave heating has successfully reduced seed borne

infection.

There is numerous report of potentially valuable biological control microorganism for seed

treatment but the developmental process to bring these into commercial practice is long and

arduous.Mode of application of seed treatment with chemicals is also an important area to be

discussed.

Traditional dust or slurry application of seed treatment fungicides are now regarded as

inefficient in environmentally hazardous.

Application of chemical or bio pesticides in film coatings or pallets reduces the loss of

material and allows the delivery of multiple products.Bio- protectants and chemical pesticides

provided effective control when added together in solid matrix priming.

g. Resistance

No example could be found of resistance especially to seed transmission of fungal or

bacterial pathogen in the planted field.However cultivar specific resistance to seed transmission

has been reported for BSMV in barley, PsbMV in peas, SMV in soybeans and AMV in alfalfa.

Conclusion

A review of the literature on seed pathology over the period (1982-94) indicates that almost

a quarter of approximately 2000 citations simply catalogued the presence of microorganisms on

seed. These purely descriptive commentaries do not address the potential for crop damage by

planting diseased seeds or the management of seed borne diseases.

Indiscriminate cataloguing of seed-borne microorganism on seeds obscures seed-borne

pathogens that might be of genuine economic importance. Viruses and bacteria that traditionally

have been neglected for lack of adequate assays.

Priority should be given to pathogens that meet the criteria of limited distribution and of

potential economic importance, as in the class of maize chlorotic mottle.

Research on inoculum thresholds is both complex and expensive, but it is so fundamental

to realistic and effective management of seed transmission of plant pathogens that little

improvement in the seed health system worldwide will be possible unless priorities in seed

pathology research are changed.

“Guidelines for safe movement of germplasm”, sponsored by the International Board for

Plant Genetic Resources, can lead to management system for seed diseases that protect against

the spread of economically important plant pathogen without posing unnecessary barriers to the

movement of seeds.


- 215 -

Climate Change in the Hilly Regions

N.S. Murty Department of Agrometeorology, G.B.P.U.A.&T., Pantnagar-263145 (Uttarakhand)

Climate change is one of the most important global environmental challenges facing

humanity with the implications on food production, natural ecosystems, freshwater supply, health,

etc. According to latest assessment, the earth’s climate system has demonstrably changed on

both global and regional scales since pre-industrial era. Further evidence shows that most of the

warming (of 0.10C per decade) was observed over the last 50 years which is attributed to human

activities. The Intergovernmental Panel on Climate Change (IPCC) projects the global mean

temperature may increase between 1.4 and 5.8 degrees Celsius by 2100. This unprecedented

increase in temperature is expected to have severe impacts on the global hydrological cycle,

ecosystems, rise in sea level, crop production and related processes. The impact would be

particularly severe in the tropical areas, which mainly consists of developing countries, including

India (Sathaye J., et al, 2006)

Why we should care?

The IPCC (2001) has estimated that the global average temperature will rise by several

degrees centigrade during this century. World temperature has increased by around 0.4ºC since

1970s, and now exceeds the upper limits of historical variability. Climatologists assess that most

of the increase is due to human interference . Potential health impacts of climate change in the

world scenariowould influence the functioning of ecosystems and their member species. Likewise,

there would be impacts on human health. Some of these health impacts would be beneficial. For

example, milder winters would reduce the peak seasonal winter deaths that occurs in temperate

countries, while in tropical regions, further increase in temperatures might reduce the viability of

disease transmitting mosquito population. Overall, however, scientists consider that most of the

health impacts of climate change would be adverse.

Impacts of climate change

The evidence shows that greenhouse gas concentrations are warming the world's climate

and the research focuses on likely impacts under different warming scenarios. Agriculture is a key

focus due to its links with the weather and climate, as well as the demand for staple food

commodities. Although there is some consensus that warming may likely to be harmful for the

agricultural enterprise in tropical and sub-tropical zones, active debate continues about whether

warming will be a net gain or loss for agriculture in the temperate countries such as United States

and Europe ( Darwin 1999, Kelly et al. 2005, Ashenfelter and Storchmann 2006, Deschenes and

Greenstone 2006).

Climate change threatens the environment by:

(i) adversely affecting natural resources (agriculture, forests, fisheries, coral reefs, mangroves,

etc), which are a major source of income.


- 216 -

(ii) the availability of fresh water and its quality, especially in many arid- and semi-arid areas

(iii) adversely affecting human health by degrading air quality and by increasing exposure to

vector- and water-borne diseases; and

(iv) increase in natural disasters, e.g.., floods and droughts and their vulnerability to ecological

degradation.

Climate change in Indian scenario

India is a large developing country with nearly 700 million rural population depending on

climate-sensitive sectors (agriculture, forests and fisheries) and natural resources (such as water,

biodiversity, mangroves, coastal zones, grasslands) for their subsistence and livelihood (National

Communications Report of India to the UNFCCC, 2004).

The latest high resolution climate change scenarios and projections for India, based on

Regional Climate Modelling (RCM), known as PRECIS developed by Hadley Center and applied to

Indian conditions using IPCC scenarios A2 and B2 (Rupa Kumar, K. et al 2005) shows that:

1. An annual mean surface temperature rise by the end of century, ranging from 3 to 50C

under A2 scenario and 2.5 to 40C under B2 scenario, with more pronounced warming in the

northern parts of India.

2. A 20% rise in all India summer monsoon rainfall and further rise in rainfall is projected over

all states except Punjab, Rajasthan and Tamil Nadu, which shows a slight decrease.

3. Extremes in maximum and minimum temperatures are also expected to increase and

similarly extreme precipitation events also show a substantial increase, particularly over the

west coast of India and west central India.

Climate change in Uttarakhand

According to the Intergovernmental Panel on Climate Change (IPCC), the increase in

global temperatures will continue during the 21st century because of greenhouse gas emissions.

The anticipated effect on the environment and people’s livelihoods in the Himalayan region could

be substantial. Several scenarios for climate change have been predicted for the Himalayas.

Climate changes will interact with changes in plant communities and habitat. Changes in land use

and vegetation are a blend of ongoing natural and anthropogenic mechanisms. These changes in

climate, vegetation, and land use in the region will have impacts on human and their health.

Uttarakhand state has varied topographical features ranging from high hills to tarai region

thereby the State experiences altogether varied climatic conditions. The plains and valleys are

hotter in summers as compared to hills. The valleys are cooler in winters. The region has wide

variations in topography as well as weather. Agriculture is mainly rainfed. Major production

constraints are low temperature, erratic distribution of rainfall and short growing season. The major

crops of the region are small millets, under utilized crops like amaranth, rice bean, buck wheat etc.

Irrigated rice is grown predominantly in valleys and upland rice is cultivated at higher elevations.

The mid hill region of the state supports off-season vegetable crops (Murty et al. 2002). The

temperatures fall rapidly during October and drops down to sub-zero temperatures during winters


- 217 -

in the region. The fall in temperature greatly influences the crop growth and agricultural production.

In mid Himalayan region during grain filling stage of amaranth, even 1° C drop in minimum

temperature in October, drastic yield reduction was observed (Murty & Singh, 2004). The diurnal

temperature variations in the region are small therefore, temperature plays an important role in

crop production. Hence an attempt is made to study the temperature variation in mid Himalayas

region. Such studies have attempted by different authors in different parts of the India (Pant and

Hingane, 1988, Jain and Dubey, 1991, Samui and Gupta, 1992, Attri et al., 1995).

The trend and moving average (3-year, 5-year and 10-year) of both maximum and

minimum temperatures were calculated and the results are as follows:

Minimum temperature

The minimum temperature trends are presented in Fig 1. The trend of minimum

temperature from 1982-2002 indicates very little increasing trend while the moving average trends

show slight decline in temperatures. Similar results were reported by Ram Singh (2003). He

observed that in maximum number of months, the minimum temperature departure was near

normal followed by decrease in minimum temperature at Hisar.

The moving averages for 3-year, 5-year and 10-year interval were calculated for minimum

temperature during the study period and a decreasing trend was found in all the three cases. The

data of 5 year and 10 year moving averages were closely followed the trend line. The trend shows

an increase of 0.002°C / year in case of minimum temperature. The moving average trends varied

between 0.006°C/year to 0.024°C/year with a negative trend.

The seasonal trend of minimum temperature is presented in Fig. 2. The seasonal analysis

indicates that the minimum temperature shows an increasing trend during summer, winter and

post rainy seasons while a sharp decline was observed during rainy season. The variation was

around 0.05°C/year. The temperature variations were more in rainy season and less in post rainy

season. The standard deviation (SD) and coefficient of variation (CV) of minimum and maximum

temperatures are presented in table 1. The SD and CV were lowest in rainy season. Highest CV

of 39.7 per cent was observed during winter season.

Table 1: Seasonal variation of temperature °C (Maximum and minimum)

Seasons Temperature (°C)

Minimum Maximum

Mean SD CV% Mean SD CV%

Winter

Summer

Rainy

Post rainy

3.0

10.3

16.1

8.4

1.19

1.33

0.94

1.34

39.7

13.0

5.8

16.1

12.8

22.0

24.1

19.1

1.08

1.81

2.26

0.99

8.4

8.2

9.3

5.2

The season wise pentad trends were presented in table 2. In all the four

seasons,increasing trend was observed during the pentad 1983-87 which may be due to the

drought year of 1987. In the other three pentads decreasing trend was observed during rainy,


- 218 -

winter and summer seasons. During post rainy season, an increasing trend was observed in the

pentad 1988-92 while it was decreasing in the next 10 years. Similarly, Singh et al. (1999)

observed that minimum temperature trend was increasing at Jodhpur while it was decreasing at

Pali. Nath and Deka (2002) found that deviations from normal during October to December months

were positive while in the rest of the months it was negative.

Table 2: Slope values of regression lines of various pentads during different seasons.

Pentads Temperature (°C)

Minimum Maximum

Winter Summer Rainy Post rainy

Winter Summer Rainy Post rainy

1983-87

1988-92

1993-97

1998-2002

1.21

-0.187

-0.297

-0.443

0.910

-0.053

-0.417

-0.133

0.435 -

0.058 -

0.330 -

0.930

1.385

0.487

-0.280

-0.637

0.393 -

0.367 -

0.187

0.040

-0.773

-0.370

-0.103

0.047

-1.428

0.298 -

0.043

5E-15

-0.310

-0.300

-0.275

0.220

Maximum temperature

The maximum temperature (Fig.1) trend was found to be negative which is 0.13°C/ year.

The moving averages also indicated that maximum temperature was decreasing over the period of

study. Compared to the minimum temperature the deviation of maximum temperature was less.

The data is almost following the trend line. The trend line equations are presented in Fig 1.

The seasonal variations of maximum temperature are presented in Fig. 2. The maximum

temperature shows declining trend during all the four seasons. In rainy season, the decrease was

up to 4.8°C during the period 1982-2002 which accounts for 0.29°C/year. The coefficient of

variation was highest during rainy season (9.3%) while it was lowest (5.2%) during post rainy

season. The SD varied between 0.99 and 2.26 over the four seasons.

The pentad trends of maximum temperature are presented in table 2. During the last

pentad (1998-2002) increasing trend was observed in all the four seasons. During rainy season, it

was almost stable. During winter season, decreasing trend was observed in the pentads 1988-

1992 and 1993-97 while it was reverse during the other two pentads. During summer and post

rainy season decreasing trend was observed except pentad 1998-2002. During the pentad 1988-

92 rainy season maximum temperature has shown an increasing trend. Contrary to these

findings, Singh et al. (1999) has found that the maximum temperatures are increasing at Jodhpur

and Pali. At Jorhat, positive deviations are found during January, February, May, June and

October to December while it was negative during the rest of the year (Nath and Deka, 2002). The

temperature analysis indicates increasing trends in all the seasons except monsoon, which shows

overall decreasing tendency for most of the station in the western Himalayan region (Pant et al.,

1999).

From the above studies it can be concluded that the maximum temperature has shown

decreasing trend while the minimum temperature is almost stable during the period of study at Hill


- 219 -

Campus, Ranichauri. The seasonal variation of minimum temperature has indicated that the

trends are increasing in all the seasons except rainy season. The maximum temperature was

found to be increasing during the last pentad i.e. 1998-2002 in all the four seasons.

In Doon valley (Negi et al, 2003), the mean maximum temperature varies between 27.1 -

28.7° C. It fluctuates around 27.5°C and on comparison of the period 1931-35 with 1996-2000

there is an increase of 0.5°C. However, sudden rise in mean maximum and minimum temperature

during 1951-55 is clear indication of deforestation. It has been observed that there is a decline of

1.1°C in mean minimum temperature during past 70 years. Fluctuations in temperature and

rainfall have pronounced effect on the distribution of evergreen and deciduous tree species.

Change in climatic pattern and micro climatic conditions have noticeable impact on forest decline.

Atmospheric carbon dioxide enrichment has put a positive response in enhancing the productivity

of these ecosystems.

The climatic changes in Darjeeling hills (Times of India 3.7.02) have caused concern

among local environmentalists. The changes in monsoon pattern has been observed and it has

been reported that the monsoon period has reduced from 4 months to one and half month, though

the annual rainfall amount remained the same. The growth of Eupatorium species reflects the rise

in temperature.

In order to manage the impacts of climate change on glaciers, the nature of these impacts

with respect to individual glaciers or drainage basins need to be understood. In Himalayas

although there are been research at large scale on glacier retreat, there has been no work at the

scale of individual glaciers or drainage basins and so current research is too general to derive

policy response.


- 220 -

Fig 1.Trends of Minimum and Maximum temperatures at Hill Campus,Ranichauri.


- 221 -

Fig. 2: Seasonal Trends of Minimum and Maximum Temperatures

Rupakumar et al. (2006) revealed that most models project enhanced precipitation during

the monsoon season particularly over northwestern India. However, the magnitudes of projected

changes differ considerably from one model to the other. There is very little or no change noted in

the monsoon rainfall over a major part of peninsular India. As far as temperature trends in the

future are concerned all the models show positive trends indicating wide spread warming into the

future. Examination of spatial patterns of an annual temperature changes in the two future time

slices (1961-1990 data has been simulated and future scenario for 2071 to 2100 has been

projected using different models) for different models indicates that the warming is more

pronounced over northern part of India. The different models/experiments generally indicate the

increase of temperature to be of order of 2 to 5 °C across the country. The warming is more

pronounced in winter and post monsoon months compared to the rest of the year.

Research priorities

1. For biologists, Incorporation of climate change into planning

2. Climate change scenarios at the regional scale

3. Reduced uncertainty among models

4. Data on climate variation over the last many years (at the hundred scales), in particular for

areas of high conservation importance (“hotspots”).

5. Understanding the variation in climate experienced by species in an assemblage in the

past will help predict their response to future change

6. Improved predictions of the frequency and magnitude of extreme events


- 222 -

REFERENCES

1. Anonymous. 2006. Mountain climate change trends could predict water resources. Science Daily, 25.Aug.

2. Ashenfelter, Orley and Karl Storchmann, 2006. Using a Hedonic Model of Solar Radiation to Assess the Economic Effect of Climate Change: The Case of Mosel Valley Vineyards,"NBER Working Paper 12380.

3. Asnani, G.C. 1993. Tropical Meteorlogy Vol.1 Published by G.C.Asnani, 822, Sindh Colony, Aundh, Pune PP. 205-268.

4. Attri, S.D., Pandya, A.B and Dubey, D.P. 1995. Forecasting of minimum temperature over gangtok, Mausam 46(1): 63-68.

5. Climate Change 2001: Synthesis Report, Intergovernmental Panel on Climate Change, Geneva, Switzerland, 2001.

6. Deschenes, Olivier and Michael Greenstone. 2006.The Economic Impacts of Climate Change: Evidence from Agricultural Prots and Random Fluctuations in Weather," Center for the Study of Energy Markets Working Paper 158,

7. India’s Initial National Communications to the United Nations Framework Convention on Climate Change, Ministry of Environment and Forests, New Delhi, 2004.

8. Jain, C.K. and Dbey, D.P. 1991. Variation of minimum temperature over Bhopal, Vayu Mandal 20(3-4):115-119.

9. Kelly, David L., Charles D. Kolstad, and Glenn T. Mitchell, 2005. Adjustment costs from environmental change," Journal of Environmental Economics and Management, 50 (3), 468-495.

10. Murty, N.S., Singh, R.K.and Uniyal, S.P. 2002 Studies on climate based vegetable crop rotation in the mid Himalayan region of Uttaranchal. Environment, Energy and Development Ed. S.B.Singh, National Geographical Society of India, Pub.44: 91-96.

11. Nath, K.K. and Deka, R.L. 2002. Perturbation of climatic elements of Jorhat. Assam J. Agromet 4(1):87-91.

12. Negi, J.D.S., Chauhan, P.S. and Negi Mrudula. 2003. Evidences of climate change and its impact on structure and function of forest ecosystems in and around doon valley. Indian Forester June 2003:757-769.

13. Pant, G.B and Hingane. L.S. 1988. Climate changes in and around the Rajasthan desert during 20th century. J.Climatology 8: 391-410.

14. Pant G.B., Rupa Kumar, K and Borgaonkar, H.P. 1999. Climate and its long term variability over the western Himalaya during the past two centuries. The Himalayan environment. Ed.S.K.Dash and J.Bahadur, New Age International (P) Ltd, 171-184.

15. Rao, G.S.L.H.V.P. 2003.Agricultural Meteorology Published by Kerala Agricultural University Press, Trichur PP. 296-313.

16. Ravindranath, N. H. and Sathaye, J., 2002.Climate Change and Developing Countries, Kluwer Academic Publishers, Dordrecht, Netherlands.

17. Rupa Kumar K, Sahai, A.K., Krishna Kumar, K, Patwardhan, S.K., Mishra, P.K. Revadekar. J.V.,Kamala, K and Pant, G.B. 2006. High resolution climate change scenarios for India for the 21st Century, Current Science 90(3): 334-345.

18. Sathaye Jayant , Shukla P. R. and Ravindranath N. H., 2006. Climate change, sustainable development and India: Global and national concerns Current Science, 90(3): 314-325

19. Samui, R.P. and Gupta, D.C. 1992. Severe winter associated with cold waves at two hill stations in Sikkim, Vayu Mandal 22(1-2): 52-56.

CHAIRMAN’S ADDRESS by

Prof. B.S. Bisht

Vice-Chancellor


on

January 02, 2009

It is a pleasure having to deliver the

chairman’s address on the successful

completion of the CAS training on “Recent

Advances in Plant Disease Management”

(December 13, 08 to January 02, 2009). I

am sure that you all have enjoyed the

scientific interaction during your stay at

Pantnagar as well as exposure trip to

Ranichauri (December 26-30, 08).

In my view, the greatest threat to

the well-being of mankind is over

population. Human population is projected

to grow at ca 80 millions per annum,

increasing by 35% to 7.7 billion by 2020

and then by about 75% before leveling off

at about 10 billion. This increased

population density, coupled with changes

in the dietary habits in developing

countries towards high quality food and the

increasing use of grains for livestock feed,

is projected to cause the demand for grain

production to more than double. However

land suitable for agriculture production is

limited, and most of the soil with high

productivity potential are already under

cultivation. In addition, the availability of

water is restricted, and in some regions

land resources are depleted and the

cultivated area is shrinking. Given these

limitations, sustainable production at

elevated levels is urgently needed. The

availability and conservation of fertile soils

and the development of high-yielding

varieties are the major challenges to

agriculture production. And, safeguarding

crop productivity by protecting crops from

damage by weeds, pests and pathogens is

also a major requisite for providing food

and feed in sufficient quantity and quality.

Improved crop management

systems based upon genetically improved

cultivars, enhanced soil fertility via

chemical fertilization, pest control via

synthetic pesticides, and irrigation were

the hallmarks of the Green Revolution.

The combined effect of these factors

allowed world food production to double in

the past 35 years. The three annual crops

viz., rice, maize and wheat, occupy almost

40% of the global crop land and are the

primary sources for human nutrition world

wide. As yield of these and some cash

crops positively respond to high production

levels and/or cultivation may be largely

i

mechanized, in the last decades, world-

wide crop production has focused on a

limited number of plant species. Diverse

ecosystems have been replaced in many

regions by simple agro-ecosystems, which

are more vulnerable to pest attack. In

order to safe guard productivity to the level

necessary to meet the demand, these

crops have to be protected from pests.

The yield of cultivated plants is

threatened by competition and destruction

from pests, especially when grown in large

scale monocultures or with heavy fertilizer

applications. However, problems created

by diseases are highly ignored and in most

cases control measures are inadequate

and in others unknown. The consequence

is poor grain, dissemination and buildup of

various diseases and yields far below the

potential. An improvement in quality and

health of plants constitutes a large

unexploited potential for increased food

production of unknown dimensions.

As I reminded you earlier in my

inaugural address, Plant Disease

Management remains one of the pathways

to achieving the UN Millennium

Development Goal relating to the

elimination of hunger and poverty. There

is, thus, every need to avoid or minimize

losses caused by plant diseases before

and after crop harvest, which can augment

the over all food production and per capita

availability. Undoubtedly, the science of

Plant Pathology in general and integrated

pest management in particular, has an

important role in the future success of

programs and policies designed to

increase and sustain food production.

I am delighted to know that all

above points have been appropriately

addressed in this particular training course,

which I am sure was very well designed

and appropriately conducted.

It is hoped that you would use the

knowledge gained through the training in

teaching, research and extension activities

at your respective institution/university.

You are now in a way alumini of this

university and I am sure that you will

maintain this linkage in a dynamic manner

for our mutual benefit in the pursuance of

science of Plant Pathology, especially in

the area of plant health management.

I wish you a safe and comfortable

return journey back home and fruitful

professional career ahead.

‘Jai Hind’

ii

ANNEXURE-I

CENTRE OF ADVANCED STUDIES IN PLANT PATHOLOGY

College of Agriculture, Pantnagar-263 145 (Uttarakhand)

Following committees have been constituted for smooth conduct of the training

programme on “Recent Advances in Plant Disease Management” scheduled on

December 13, 2008 to January 02, 2009.

1. Overall Supervision

Dr. J. Kumar, Director CASPP

Dr. S. C. Saxena

Dr. K.P. Singh

Dr. R.P. Singh

Dr. A.P. Sinha

Dr. H.S. Tripathi

2. Course Faculty

Dr. J. Kumar – Course Director

Dr. S.C. Saxena, Course Coordinator

Dr. H.S. Tripathi

Dr. A.P. Sinha

Dr. R. P. Awasthi

Dr. (Mrs.) K. Vishunavat

3. Inaugural and Closing Function Committee

Dr. H.S. Tripathi– Chairman

Dr. A.K. Tewari

Mr. Narender Singh

Mr. S.P. Yadav

Mr. Mani Ram

4. Inaugural Session & Intersession Tea Committee

Dr. H.S. Tripathi – Chairman

Dr. K.K. Mishra

Dr. Ajeet Kumar

Mr. S. P. Yadav

Mr. Jagannath

5. Budget Committee

Dr. R. P. Awasthi – Chairman

Dr. Yogendra Singh

Mr. K. S. Bhatnagar (Account Officer)

Mr. A. B. Joshi

Mr. Praveen Kumar

Mr. Het Ram

6. Transport and Reception Committee

Dr. Pradeep Kumar – Chairman

Dr. K.P.S. Kushwaha

Mr. Prakash Joshi

Mr. Bhuwan Chand Sharma

Mr. Bhupesh Kabadwal

7. Boarding & Loading Committee

Dr. V.S. Pundhir – Chairman

Dr. R.K. Bansal

Mr. S. P. Yadav

Mr. Dev Kumar Chaube

8. Registration Committee

Dr. (Mrs) K. Vishunavat –

Chairperson

Dr. P. Kumar

Dr. (Mrs.) Kanak Srivastava

Dr. (Mrs.) Renu Singh

i

9. Session Arrangement Committee

Dr. S.C. Saxena – Chairman

Dr. P. Kumar

Dr. Y. Singh

Mr. Prakash Joshi

Mr. Vikram Prasad

10. Editing, Publication, Printing, Certificates, etc. Committee

Dr. (Mrs.) K. Vishunavat - Chairperson

Dr. A.K. Tewari

Dr. Ajeet Kumar

Mr. Praveen Kumar

Mr. P.C. Khulbe

11. Field / Excursion Trip Committee

Dr. R.K. Sahu – Chairman

Dr. M.K. Sharma

Mr. K. S. Bisht

Mr. R. B. Sachan

12. Laboratories & General Maintenance

Committee

Dr. K.S. Dubey– Chairman

Mr. A. B. Joshi

Mr. Bhupesh Chandra Kabdwal

Mr. Rajendra Pandey

13. Committee for Typing, Correspondence work

Dr. S. N. Vishwakarma - Chairman

Smt. Meena Singh

Mr. Rakesh Tewari

Mr. Mehboob

14. Audiovisual Aid & Publicity Committee

Dr. A.P. Sinha-Chairman

Dr. A.K. Tewari

Mr. R.C. Singh

Mr. Bupesh Kabdwal

ii

ANNEXURE-II

LIST OF PARTICIPANTS

Sl. No.

Name and Address Phone/E-mail

1. Dr. S.K. Mishra

J.R.O. Mushroom/ Junior Mycologist

Deptt. of Natural Resource Management

V.C.S. Garhwali College of Horticulture

Bharsar- 246 123 (UK)

(O): 01348-226071 (R): 01348-226039 E-mail: [email protected]

2. Dr. (Mrs.) Geeta Sharma

JRO, Plant Pathology (Mushroom)

G.B.P.U.A.&T., Hort. Res. & Extn. Centre

Jeolikote, Nainital (UK)

(O): 05942-224547 (Mb.): 9410111625

3. Dr. Subhash Chandra

Jr. Scientist, Plant Pathology, Pulse Section

Deptt. of Genetics and Plant Breeding

N.D.U.A.&T., Kumarganj, Faizabad- 224 229 (UP)

(O): 05270-262051 (Mb.): 9450768159 E-mail: [email protected]

4. Dr. Anuj Saxena

Sr. Lecturer & Head, Department of Botany

Sacred Heart Degree College

Sitapur- 261 001 (UP)

(O): 05862-220133 (R): 9415150522 E-mail: [email protected]

5. Dr. Sandeep Kumar

SMS (Plant Protection)

KVK, Basuli, Maharajganj,NDUA&T,

Kumarganj, Faizabad, (UP)

(Mb.) 9919206641 E-mail: [email protected]

6. Prof. Daunde Anand Tulshiram

Assistant Professor, Tissue Culture Project

Marathwada Agricultural University

Parbhani- 431 402 (MS)

(O): 02452-228933 (Mb): 9049030880 E-mail: [email protected]

7. Shri. Ramesh Laxmanrao Parate

Assistant Professor, Plant Pathology

College of Agriculture, Nagpur

Dr. PDKV, Akola, Nagpur- 440 001 (MS)

(O): 0712-2531128 (R): 0712-2735418 (Mb.) 9423164919

8. Dr. Zahoor Ahmed Bhat

Subject Matter Specialist/Jr. Scientist

Krishi Vigyan Kendra, Anantnag

SKUAST-K, Shalimar

Srinagar- 192 233 (J&K)

(O): 09858083463 (R): 01942462532 E-mail: [email protected]

i

9. Dr. Mushtaq Ahmad Bhat

Asstt. Prof./SMS (Plant Pathology)

KVK-Baramulla, SKUAST-K, Shalimar

Srinagar- 193 502 (J&K)

(O): 09906965820 (R): 0194-2463008 E-mail: [email protected]

10. Dr. Ashish Yadav

Scientist ‘C’

Defence Institute of High Altitude Res.

Defence Res. & Development Organization

C/o 56 APO, Leh-Ladakh-901 205 (J&K)

(O): 01982-252096 (Mb): 09419176078 E-mail: [email protected]

11. Dr. Ajit Kumar Jha

SMS (Plant Protection)

Krishi Vigyan Kendra

Garhwa (Near District Agril. Farm)

Birsa Agricultural University, Ranchi, Garhwa (Jkd)

(Mb.): 9431333148

12. Dr. Ayon Roy

Lecturer (Assistant Prof.) in Pl. Path.

AINP on Jute & Allied Fibres

Uttar Banga Krishi Viswavidyalaya

Cooch Behar- 736 165 (WB)

(O): 03582-270633 (Mb): 09434483593 E-mail: [email protected] [email protected]

13. Dr. Sanjeev Kumar

Assistant Professor/Scientist, Pl. Pathology

College of Agriculture Ganj Basoda

(RVSKVV) Gwaliar (MP)

(O): 07594-224159 (Mb.) 9406958850

14. Shri. Ashok Kumar Choudhary

Assistant Professor

B.M. College of Agriculture, Khandwa

R.V.S.K.V.V., Gowaliar- 450 001 (MP)

(O): 0733-2230217, 2222119 (R): 0733-2227813 (Mb) 9406678194 E-mail: [email protected]

15. Shri Pawan Kumar Chaudhari

Asstt. Prof.-cum-Jr. Scientist

Department of Plant Pathology

Rajendra Agricultural Univ., Bihar, Pusa

Samastipur- 848 125 (Bihar)

(M): 09470410763 E-mail: [email protected] [email protected]

16. Dr. Kantilal Karshanbhai Patel

Asstt. Professor (Selection Grade)

Department of Plant Pathology

C.P. College of Agriculture

S.D. Agricultural University

Sardarkrushinagar- 385 506 (Gujarat)

(O): 02748-278489 (R): 02742-252036 (Mb.) 9998815195 E-mail: [email protected]

ii

17. Dr. R.F. Chaudhary

Assistant Professor, Deptt. of Plant Pathology


S.D. Agril UniversityTa: Dantiwada, Distt. B.K.



18. Dr. Amrutbhai Ghemarbhai Desai

Assoc. Professor, Department of Plant Pathology


S.D. Agricultural University

Ta- Dantiwada, Distt. B.K.


(O): 02748-278489 (Mb.) 09427643291 E-mail: [email protected]

19. Dr. Rakesh Kumar Sharwanlal Jaiman

Asstt. Research Scientist (Plant Pathology)

Centre for Research on Seed Spices

S.D. Agril UniversityJagudan

(Distt. Mehsana)- 382 710 (Gujarat)

(O): 02762-285337 (R): 09427989534 Mb. 9427676112 E-mail: [email protected]

20. Dr. K. Sethuraman

Assoc. Prof. Deptt. of Plant Pathology

Agricultural College and Research Institute

Tamil Nadu Agricultural University

Madurai- 625 104 (TN)


S U M M A R Y

Sl. No. State No. of participants

1 Bihar 01

2 Gujarat 04

3 Jharkhand 01

4 Jammu & Kashmir 03

5 Madhya Pradesh 02

6 Maharashtra 02

7 Tamil Nadu 01

8 Uttarakhand 02

9 Uttar Pradesh 03

10 West Bengal 01

Total Participants 20

iii

ANNEXURE-III

TRAINING

ON

RECENT ADVANCES IN PLANT DISEASE MANAGEMENT

(December 13, 08 to January 02, 09)

Venue Committee Room, Department of Plant Pathology

Sponsored by Centre of Advance Studies in Plant Pathology (ICAR, New Delhi)

Faculty Dr. J. Kumar, Director CAS Plant Pathology

Dr. S.C. Saxena, Course Coordinator

Dr. A.P. Sinha, Professor

Dr. H.S. Tripathi, Professor

Dr. R.P. Awasthi, Professor

Dr. (Mrs.) K. Vishunavat, Professor

GUEST SPEAKERS/CONTRIBUTORS Dr. (Mrs.) Abha Agnihotri Fellow, Plant Biotechbology, TERI, & Adjunct Faculty, TERI

University, TERI (The Energy & Resources Institute), Darbari Seth Block, Habitat Place, Lodhi Road, New Delhi

Dr. Ram Kishun Principal Scientist (Plant Pathology), Central Institute of Subtropical, Horticulture, Rehmankhera, Post: Kakori, Lucknow

Dr. R.J. Rabindra Project Directorate of Biological Control, H.A. Farm Post, Bangalore

Dr. K.N. Pathak Chairman, Department of Nematology, Rajendra Agricl. University, Pusa, Distt. Samsatipur (Bihar)

Dr. R.C. Rai Head, Deptt. of Plant Pathology, Rajendra Agricl. University, Pusa, Distt. Samsatipur- 848 125 (Bihar)

Dr. H.N. Gour Prof. & Head, Division of Agri. Plant Nematology, Rajasthan College of Agriculture, Udaipur, MPUA&T, Udaipur

Dr. A.U. Siddique Prof. & Head, Division of Agri. Plant Nematology, Rajasthan College of Agriculture, Udaipur, MPUA&T, Udaipur

Dr. Bir Pal Singh Joint Director, Central Potato Research Centre, Modipurum- Meerut

Dr. Akhtar Haseeb Chairman, Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim Univ., Aligarh

Dr. T. S. Thind Professor Department of Plant Pathology, College of Agriculture, Punjab Agricultural University, Ludhiana

Dr. M.C. Nautiyal Dean, College of Forestry and Hill Agriculture, G.B.P.U.A.&T., Hill Campus, Ranichauri

Dr. Y.P. Sharma Principal Scientist & Head, Directorate of Wheat Research, Regional Research Station, Flowerdale, Shimla

Dr. R.K. Khetrapal Head of the Plant Quarantine Division, NBPGR, IARI, Pusa Campus, New Delhi

i

Dr. Yogesh Negi Department of Microbiology, SBS PG Institute of Bio-medical Sciences & Res., Balawala, Dehradun

Dr. K.P. Singh SRO, Plant Pathology, Hill Campus, G.B.P.U.A.&T., Ranichauri

Dr. Y.P. Singh Forest Pathology Division, Forest Research Institute, Dehradun

Dr. S.P.S. Beniwal Ex-Regional Coordinator, ICARDA

Dr. R.D. Kapoor Regulatory Lead, Monsento India Ltd., 6-B Jorbagh Lane Ground Floor- New Delhi- 110 063

LOCAL SPEAKERS

Dr. J.P. Tiwari Dean, College of Agriculture

Dr. J. Kumar Professor and Head-cum-Director CAS Plant Pathology

Dr. K.P. Singh Director Extension Education

Dr. S.C. Saxena Professor (Guest Faculty), Plant Pathology

Dr. A.P. Sinha Professor, Plant Pathology

Dr. H.S. Tripathi Professor, Plant Pathology

Dr. S.N. Vishwakarma Professor, Plant Pathology

Dr. R.P. Awasthi Professor, Plant Pathology

Dr. (Mrs.) K. Vishunavat Professor, Plant Pathology

Dr. V.S. Pundhir Professor, Plant Pathology

Dr. R.K. Sahu Professor, Plant Pathology

Dr. Y. Singh SRO, Plant Pathology

Dr. A.K. Tewari SRO, Plant Pathology

Dr. K.K. Mishra JRO, Plant Pathology

Dr. M.A. Khan Professor & Head, Entomology

Dr. B. Mishra Professor, Soil Science

Dr. P.C. Srivastava Professor, Soil Science

Dr. A.K. Agnihotri Professor, Soil Science

Dr. H.S. Kushwaha Professor, Soil Science

Dr. D. Roy Professor, Genetics and Plant Breeding

Dr. H.S. Chawla Professor, Genetics and Plant Breeding

Dr. Ruchira Tiwari Asstt. Prof., Entomology

Dr. N.S. Murty Professor, Agrometeriology

Dr. B. Kumar Professor & Head, Agriculture Communication

Dr. Anil Kumar Professor and Head, MBGE

Dr. S. Marla Assoc. Professor, MBGE

Dr. Reeta Goel Professor & Head, Microbiology

Dr. Anil Sharma Assoc. Prof., Biological Science

Dr. Balwinder Singh Assoc. Prof., Vet. Anotomy

Dr. Arundhati Kausik Assistant Librarian

ii

ANNEXURE-IV

CENTRE OF ADVANCED STUDIES IN PLANT PATHOLOGY

G.B. Pant University of Agri. & Tech., Pantnagar-263 145

Course Schedule (December 13, 08 to January 02, 09)

“RECENT ADVANCES IN PLANT DISEASE MANAGEMENT”

Venue : PG Lab- Department of Plant Pathology

Day & Date Time Topic ( Lecture/ Lab) Speaker/Contact

Saturday

Dec. 13

09:30-10:15 hrs Registration Registration committee, PG Lab, Plant Pathology

10:15-11:30 hrs Inaugural Function

Venue: Conference Hall, Agriculture College

11:30-11:45 hrs Tea Break

11:45-13:00 hrs Introduction with Plant Pathology Faculty & Visit to

Plant Pathology Labs

PG Lab, Plant

Pathology

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit-CD-ROM search (University Library) Dr. Arundhati

Kaushik

Sunday

Dec. 14

09:30-12:30 hrs Quality spawn Production and visit to different units

of MRTC

Dr. K.K. Mishra

Monday

Dec. 15

09:30-10:30 hrs IPR & WTO in relation to plant protection- Dr. H.S. Chawla

10:30-11:30 hrs Addressing Nutritional deficiencies and toxicities for

crop health management

Dr. P.C. Srivastava


11:45-13:00 hrs Use of GIS & GPS in plant disease management Dr. A.K. Agnihotri

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit to CRC, LRC, HRC, VRC, University Campus Dr. R.K. Sahu

Tuesday

Dec. 16

09:30-10:30 hrs Soil Heath & plant disease management Dr. B. Mishra

10:30-11:30 hrs Biotechnological approaches for in corporation of

fungal disease resistance

Dr. Abha Agnihotri,

Delhi


11:45-13:00 hrs College of Agriculture at a glance Dr. J.P. Tewari,

Dean

13:00-14:30 hrs Lunch

14:30-15:30 hrs Discussion with participants Dr. Abha Agnihotri


15:45-17:00 hrs Recent advances in integrated management of

vegetable diseases

Dr. S.N.

Vishwakarma

Wednesday

Dec. 17

09:30-10:30 hrs Managing diseases through host resistance Dr. D. Roy

10:30-11:30 hrs Department of Plant Pathology and CAS activities at

Pantnagar

Dr. J. Kumar,

Director CAS in PP


i

11:45-13:00 hrs Advances in the management of wilt of chick pea

and pigeon pea diseases

Dr. H.S. Tripathi

13:00-14:30 hrs Lunch

14:30-15:30 hrs Micro-meteorology in relation to plant disease

development

Dr. H.S. Kushwaha


15:45-17:00 hrs Field & Lab visit on meteorology Dr. H.S. Kushwaha

Thursday

Dec. 18

09:30-10:30 hrs Technology transfer in extension: experiences from

Uttarakhand.

Dr. K.P. Singh, DEE

10:30-11:30 hrs Recent advances in the management of bacterial

disease of sub-tropical fruits

Dr. Ram Kishun,

Lucknow


11:45-13:00 hrs Innovation in biological control of insect pest of

economic importance

Dr. R.J. Rabindra

13:00-14:30 hrs Lunch

14:30-17:00 hrs Advances in electron microspy and application in

plant pathology

Dr. Balvinder Singh

Friday

Dec. 19

09:30-10:30 hrs Advances in eco-friendly approaches in IPM Dr. Ruchira Tewari

10:30-11:30 hrs T.A. Business Dr. R.P. Awasthi


11:45-13:00 hrs Advancement in seed health testing for better

disease management

Dr. K. Vishunavat

13:00-14:30 hrs Lunch

14:30-15:30 hrs Application of genomics & bioinformatics in plant

disease management

Dr. S. Marla


15:45-17:00 hrs Laboratory on introduction to bioinformatics tools for

crops experiments data analyses

Dr. S. Marla

Saturday

Dec. 20

09:30-10:30 hrs Past and future of immunological assays for the

detection of plant pathogens

Dr. Anil Kumar

10:30-11:30 hrs Practical Discussion Dr. Anil Kumar


11:45-13:00 hrs Plant nematological contributions in phytopathology Dr. K.N. Pathak

13:00-14:30 hrs Lunch

14:30-15:30 hrs Status of karnal bunt of wheat & its management Dr. R.C. Rai, Pusa


15:45-17:00 hrs Visit to CCF Dr. A.K. Tewari

Sunday

Dec. 21

09:30-10:30 hrs Plant disease management in organic agriculture Dr. H.N. Gaur

10:30-11:30 hrs Entomopathogens Dr. A.U. Siddique


11:45-17:00 hrs Molecular detection of plant pathogens- laboratory

exercise

Dr. J. Kumar

Monday

Dec. 22

09:30-11:30 hrs Recent approaches on the management of maize

diseases

Dr. S.C. Saxena


ii

11:45-13:00 hrs Phosphate solubilizing bacteria and their role in

crop growth and disease management

Dr. Reeta Goel

13:00-14:30 hrs Lunch

14:30-15:30 hrs Trainers training- Farmers approach Dr. B. Kumar


15:45-17:00 hrs Trainers training- Farmers approach Dr. B. Kumar

Tuesday

Dec. 23

09:30-10:30 hrs Variability in Phytophthora infestans-

epidemiological consideration and disease

management

Dr. Bir Pal Singh

10:30-11:30 hrs Advances in the management of root knot

nematode

Dr. Akhtar Haseeb,

AMU


11:45-13:00 hrs New generation fungicides Dr. T. S. Thind, PAU

13:00-14:30 hrs Lunch

14:30-15:00 hrs Group Photograph Dr. H.S. Tripathi

15:00-15:45 hrs Discussion on the management of root knot

nematode

Dr. Akhtar

Haseeb,AMU


15:45-17:00 hrs Advances in sheath blight management Dr. A.P. Sinha

Wednesday

Dec. 24

09:30-11:30 hrs Plant Protection and Trade Concerns Dr. S.P. Singh, Ag.

Eco.

10:30-11:30 hrs Role and limitations of Botanicals in the

Management of Plant Diseases

Dr. A.P. Sinha


11:45-13:00 hrs Recent Advances in Management of Stalk rots Dr. S.C. Saxena

13:00-14:30 hrs Lunch

Thursday

Dec. 25

09:30-10:30 hrs Application of mycorrhizae for plant diseases

management

Dr. Anil Sharma


10:45-11:15 hrs Visit to Biocontrol lab Drs. J. Kumar/M.A. Khan

11:15-13:00 hrs Laboratory exercise on mycorrhizae Dr. Anil Sharma

13:00-14:30 hrs Lunch

Friday

Dec. 26/27

07:30 hrs Departure to Ranichauri Dr. R.P. Awasthi

Sunday

Dec. 28

09:30-10:30 hrs Role of Hill Campus in addressing problem of hill

farming

Dr. M.C. Nautiyal,

Dean

10:30-17:00 hrs Visit to Farmers Fields

Monday

Dec. 29

09:30-10:30 hrs Wheat rust resistance management Dr. Y.P. Sharma,

Shimla

10:30-11:30 hrs Management of transboundary movement of pests Dr. R.K. Khetrapal


11:45-13:00 hrs Evolution of UG 99 and its world wide threat Dr. Y.P. Sharma

13:00-14:30 hrs Lunch

14:30-15:30 hrs Discussion with participants Dr. R.K. Khetrapal

iii


15:45-17:00 hrs Role of PGPR in plant disease management Dr. Yogesh Negi

Tuesday

Dec. 30

09:30-10:30 hrs Advances in the integrated disease management of

rapeseed mustard

Dr. R.P. Awasthi

10:30-11:30 hrs Recent Advancement in the management of apple

scab

Dr. K.P. Singh,

Ranichauri


11:45-13:00 hrs Field visit Dr. K.P. Singh

13:00-14:30 hrs Lunch

14:30-15:30 hrs Advances and management of shisham wilt Dr. Y.P. Singh, FRI


15:45-17:00 hrs Mycorihaze in forest trees Dr. Y.P. Singh, FRI

Wednesday

Dec. 31

07:00 hrs Arrival at Pantnagar

09:30-10:30 hrs Current status and future prospects of GM crops in

plant disease management and ensuring food

security: An industry approach

Dr. R.D. Kapoor

10:30-11:30 hrs Soil solarization and its application in plant disease

management

Dr. Y. Singh


11:45-13:00 hrs Technologies for disease management in low input

systems

Dr. J. Kumar

13:00-14:30 hrs Lunch

14:30-15:30 hrs Epidemiological approaches to disease

management through seed technology

Dr. K. Vishunavat


15:45-16:15 hrs Participants Feed Back Dr. S.C. Saxena

16:15-17:00 hrs New Year Programme Dr. V.S. Pundhir

Thursday

Jan. 01

09:00-10:00 hrs Integrated management of major pulse disease:

Role of Botanical

Dr. H.S. Tripathi

10:00-11:00 hrs T.A. Settlement Dr. R.P. Awasthi


11:15-12:00 hrs Modeling plant disease epidemics for crop

protection

Dr. V. S. Pundhir

12:00-13:00 hrs Visit to VRC Dr. V.S. Pundhir

13:00-14:30 hrs Lunch

14:30-15:30 hrs Fingerprints of climate change and disease Dr. N.S. Murty


15:45-17:00 hrs Pathogen population considerations in developing

durable disease resistance : A case study of rice

blast pathosystem

Dr. J. Kumar

Friday

Jan. 02

09:30-11:30 hrs International Agriculture Dr. S.P.S. Beniwal


11:45-13:00 hrs Panel Discussion

13:00-14:30 hrs Lunch

14:30-17:00 hrs Closing Function Venue: Conference Hall, Ag. College

iv

Botanical in the management of Plant diseases - CiteSeerX

Documents

Transcript of Botanical in the management of Plant diseases - CiteSeerX