Cotton Pest Management

A Term Paper on

INTEGRATED MANAGEMENT OF INSECTPEST OF COTTON

Submitted toAsst. Prof. Sundar Tiwari Department of Entomology

Agriculture and Forestry UniversityRampur, Chitwan

Submitted bySushil NyaupaneENT-05M-2013

Agriculture and Forestry University

Rampur, Chitwan

July 2014

Introduction

Cotton is a soft, fluffy staple fiber that grows in a boll, or

protective capsule, around the seeds of cotton plants of the

genus Gossypium The fiber is almost pure cellulose. Under

natural conditions, the cotton bolls will tend to increase the

dispersion of the seeds. Cotton has high economic and

industrial value. The history of cotton production in Nepal

has started from 1972-73 in Banke district in the form of

small research and now this farming is being widespread in

eastern Terai part of Nepal.

Insect pests that feed on plant structures that directly

produce yield, such as growing tips and fruiting structures,

are generally the greatest problem in a cotton crop. These

pests include Helicoverpa and mirids. The cotton plant has an

indeterminate growing pattern (fruit are present for most of

the season), which allows some pests to develop through

several generations.

Major pests

Helicoverpa

Helicoverpa remains a major pest on conventional (non-

genetically modified) cotton. The two species -Helicoverpa

armigera and H. punctigera - are very similar in both appearance

and the damage they cause to cotton. However correct

identification of the species is important

because H. armigera has developed high levels of resistance to

insecticides.

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Species composition in the crop will be influenced by the time

of year and location. In temperate regions, the majority of

the H. armigera population overwinter from mid-March onwards and

emerge during September/October. Helicoverpa punctigera is usually

the dominant species through September, but seasonal variation

can lead to early infestations of H. armigera in some years.

Helicoverpa adults are mobile and produce large numbers of

eggs, leading to rapid build-up of populations under

favourable conditions. Survival is influenced by the number of

predators present as well as other mortality factors such as

wind, rainfall and temperature extremes.

Figure. Cotton bollworm (Helicoverpa armigera)

Damage

In cotton, all stages of plant growth may be attacked but

reproductive tissue is preferred. Seedlings can be 'tipped

out' when terminal buds are eaten. Chewing damage to squares

and small bolls may cause them to shed, and chewing damage to

maturing bolls may prevent normal development and can lead to

secondary fungal infections such as boll rot.

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Figure. Bollworm feeding on square

Figure. Bollworm larvae and boll damage

Monitoring and thresholds

Regular monitoring of the crop for the presence of larvae

and/or damage is necessary in order to make timely decisions

on control. This is especially important when targeting small

and possibly insecticide-resistant larvae.

Visual sampling is the recommended method. Check at least 30

plants or 3 separate metres of row for every 50 ha (larger

samples give more accurate estimates). Eggs are

not necessarily a good basis for thresholds as not all hatch

and very small larvae have high mortality rates. Assess

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beneficial insect numbers and note parasitised eggs and

larvae.

When making pest management decisions in cotton, insect

numbers alone may not be sufficient. Plant monitoring (fruit

load, yield and maturity) assists in decision making when pest

levels are just below threshold or when there are combinations

of pests.

Thresholds for conventional cotton depend on crop stage and

are:

• Seedling to flowering: 2 larvae/m or 1 larvae (>8 mm)/m.

• Flowering to cut-out: 2 larvae/m or 1 larvae (>8 mm)/m or

5 brown eggs/m.

• Cut-out: 15% open bolls - 3 larvae/m or 1 larvae

(>8 mm)/m or 5 brown eggs/m.

• 15%-40% open bolls: 5 larvae/m or 2 larvae (>8 mm)/m or

5 brown eggs/m.

Resistance

Helicoverpa armigera developed resistance against most

insecticides in the late 1990s. However, with the introduction

of genetically modified cotton, biopesticides and more

selective insecticides, insecticide resistance to older

chemistry has decreased in recent

years. Helicoverpa punctigera has no known resistance to any

insecticides but the use of more selective options is

encouraged to help preserve natural enemies.

In order to prevent insecticide resistance, the cotton

industry has developed the Insecticide Resistance Management

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Strategy (IRMS). This strategy is reviewed annually to delay

development of resistance of H. armigera to conventional

insecticides. The core IRMS principles include:

• rotation between chemical groups with different modes of

action

• limiting the time period during which an insecticide can

be used

• limiting the number of applications of one particular

insecticide.

Cultural control

Post-harvest cultivation (pupae busting) to reduce the

overwintering stage of Helicoverpa is one of the most important

cultural control practices available. Cultivation to a depth

of at least 10 cm will damage or disturb pupae, seal their

emergence tunnels and trap emerging moths. Cultivation also

leaves survivors open to attack by birds, mice, earwigs, and

wasp parasites.

Natural enemies

Beneficial insects can affect all Helicoverpa life stages:

Predators

• Egg:red and blue beetle, damsel bug, green lacewing,

brown lacewing and various ants.

• Larvae: glossy,brown and predatory shield bugs, bigeyed,

bug, damsel bug, assassin bug, red and blue beetle, brown

lacewing common

• Pupae: common brown earwig and wireworm larvae

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• Moth:spiders

Parasitoids

• Trichgramma spp. and Telenomus spp.

• Larva: tachinid flies and Microplitis demiltor

• Pupae: banded caterpillar parasite

Spider mites

The two-spotted mite (Tetranychus urticae) is the most numerous

mite species on cotton. Other species that may occur are bean

spider mite and strawberry spider mite. Mites live on the

underside of leaves and are difficult targets for aerial

sprays. Mites prefer more mature leaves and the highest

populations are usually found near the top of the plant on

main stem nodes 3-5 below the terminal. Heavy mite

infestations on cotton can originate from adjoining fields of

early sown corn from where they are carried by air currents.

Fig: spider mite on leaves

Damage

Mite infestations in seedling cotton rarely justify control

but may be a useful indicator of potential problems and should

be monitored closely. The first sign of damage is bronzing of

the upper leaf surface near the petiole or leaf fold. As

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numbers increase, the leaves turn red and become covered in

fine webbing, and affected leaves may dry and fall off. High

mite populations can significantly affect yield and quality of

cotton. The earlier in the season that infestations develop,

the greater the potential of yield loss and quality

downgrades.

Figure. Spider mite feeding damage can weaken and even kill

stressed plants


Start sampling at seedling emergence and continue at least

weekly. At low numbers, mites are difficult to find. Mites are

often too numerous to count individually, so infestations can

be rated on a presence/absence system. In Australia, the

leaves on the third to fifth main stem node (down from the

plant terminal) are the best to sample.

The general threshold for mites for most of the growing season

is 30% of plants infected. The threshold depends more on when

mite populations begin to increase and how quickly they

increase rather than the number of mites. To estimate the

percentage of yield reduction caused by mites, a chart has

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been developed by the cotton industry for the different cotton

growing regions.

Management

• Under Australian conditions, mite populations increase

less rapidly on the okra leaf varieties than broadleaf

varieties.

• Mite infestations increase after the application of some

broad-spectrum insecticides for control of other pests.

• Control weeds within fields and along field boundaries

that serve as over-wintering sites for mites.

.

Thrips are the major mite predator in cotton. Others include

damsel bug, bigeyed bug, ladybird beetles, brown smudge bug,

apple dimpling bug, brown lacewing adults, and tangle web

spiders.

Mirids (Creonitiades spp)

An important sucking insect pest of cotton, mirids are

abundant in cotton from early to mid-season and occur

throughout the cotton growing regions of Queensland and New

South Wales Green mirids are more common than brown mirids but

both cause similar damage.

Damage

Adults and nymphs feed by piercing plant tissue and releasing

a chemical that destroys cells in the feeding zone, resulting

in the following symptoms:

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• localized leaf damage

• terminal wilting of young plants

• deformity (broom shaped)

• shedding of squares and small bolls

• damage to bolls (up to 15 days old) by causing warty

growths inside carpel which causes discolored lint

• malformed bolls, delay of maturity

• reduced lint and fibre quality.


Mirids are a very mobile pest and populations can fluctuate

rapidly so sampling needs to be done every three days. The

beat sheet is the most effective means for estimating mirid

numbers. Monitor for number of mirids as well as for tip

damage and fruit retention on cotton plants. Adult cause more

damage than the first three nymphal instars while the fourth

and fifth instars do similar levels of damage as the adults.

Heavy tip damage and fruit retention levels can also have an

impact on control decisions.

Thresholds based on beat sheet sampling vary between warm and

cool areas due to the cotton plants ability to compensate for

damage.

• Warm areas. Early season: 4 mirids per metre. Mid

season: 3 mirids per metre.

• Cool areas. Early season: 2 mirids per metre. Mid

season: 1.5 mirids per metre.

Management

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• Control alternative hosts including native weeds before

crop establishment.

• Avoid broad-spectrum insecticides.

• Spray only when both insects and damage are at threshold

levels.

There is potential to use lucerne as a trap crop for mirids.

Lucerne should be established two weeks before cotton.

Research has shown that the addition of petroleum spray oils

to some chemicals improves product efficacy at lower (half)

label rates and helps preserve natural enemies. Research has

also demonstrated that the addition of salt (5g/L of water) to

dimethoate greatly improves that product's efficacy against

mirid nymphs and adults at rates as low as 33% of the

registered rate, while lessening the spray's impact on natural

enemies.

A number of beneficial species are known to feed on mirids yet

none are recognised as regulators of mirids in cotton

populations. Adults, nymphs and eggs are eaten by damsel bug,

big eyed bug, predatory shield bug and a number of spider

species.

Aphids

The cotton aphid (Aphis gossypii) is the most common aphid

pest. Green peach aphid is an occasional pest in the early

season and cowpea aphids can colonise cotton but rarely become

a problem.

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Figure. Cotton aphid in cotton leaves and cotton damage

Damage

Aphids cause early to late season damage to terminals, leaves,

buds and stems, and are known to transmit Cotton Bunchy Top

(CBT) diseases. The honeydew secreted by aphids can

contaminate lint once bolls begin to open.

Figure. Honeydew laden leaves from whitefly infestation


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Aphids tend to be patchy in distribution so sample in several

locations. At each location collect 20 leaves from different

plants (one leaf per plant) and choose main stem leaves from

3-4 nodes below the terminal of the plant. Sample for winged

and wingless adults as well as nymphs. Non-winged adults

indicate that the population has settled in the crop. Aphids

prefer new growth so focus on terminals and recently expanded

leaves. Start sampling at seedling emergence until defoliation

and sample weekly. Where hotspots of aphids are evident, also

monitor cotton for CBT.

Significant yield loss can occur if aphid populations are

allowed to develop to high levels (>90 % of plants infested)

for a period of 2-3 weeks. Thresholds depend on the estimated

yield loss which, when compared to cotton price and control

costs, helps determine whether control is warranted. When open

bolls are present thresholds should be lowered to 50% of

plants infested or 10% of plants if honeydew is present to

prevent contamination of lint.

Management

• Control weeds that serve as alternative hosts for

aphids, including marshmallow, capeweed, thistles,

nightshade, bladder ketmia and thornapples.

• Ratoon and volunteer cotton should be controlled as they

are winter hosts and may also carryover CBT disease.

• Cotton aphid has developed widespread resistance to a

number of insecticides, so adhere to the cotton IRMS.

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Whitefly

Silverleaf whitefly (Bemisia tabaci B-biotype)(SLW) and Bemisia

tabaci Q-biotype are the most serious whitefly pests in cotton due

to their resistance to many insecticides and rapid

reproduction rate. Bemisia tabaci Q-biotype is a recent arrival

in Australia (2008) and currently not as widespread as SLW.

How this biotype will affect cotton compared to SLW is not yet

known. Others found in cotton are (Trialeurodes vaporiorium) and

eastern Australian native whitefly (Bemisia tabaci).

Whiteflies are found in all cotton growing areas of

Queensland. SLW is more prevalent in warm areas. Hosts include

cotton, sunflower, tomato, rockmelon, sowthistle weed. In

cotton growing areas, SLW normally start to reach pest levels

in December through to cotton harvest. While SLW are capable

of vectoring serious cotton viruses, no such viruses are

present in Australia. SLW is highly resistant to some

insecticides and has the ability to develop resistance to

newer insecticides if resistance is not carefully managed.

Figure. Adult whitefly

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Damage

SLW feed on plant sap and cause plants to wilt, drop leaves

and under severe pest pressure, plants may die. Excretion of

honeydew contaminates lint. One of the sugars in SLW honeydew

has a lower melting point than those found in aphid honeydew

and creates problems during processing. Honeydew promotes

sooty mould, which reduces potential crop yield by blocking

sunlight and reducing assimilation of nutrients for plant

growth.


Sample once a week from first flower (777 degree days

(DD)) and then twice a week from peak flowering (1300 DD).

Sample from a minimum of 2 sites in your sample area (maximum

of 25 hectares). Count the number of adults per fifth node

leaf (sample one leaf per plant).

Thresholds are based on a scoring system. Score each leaf as

either un-infested (0 or 1 adult per leaf) or infested (2 or

more adults per leaf). Calculate the percentage of crop

infested and the crop age in day degrees as thresholds are

relative to crop development stages.

Management

• Control alternate weed hosts and consider planting cotton

away from other hosts such as soybeans, sunflower and

cucurbit crops.

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• Develop an area-wide management strategy with neighbours

including a tight planting window so that whitefly does

not migrate to successive plantings.

• Avoid early season broad-spectrum insecticides that kill

beneficial insects and subsequently flare whitefly

populations. Natural enemies play a vital role in the

management of SLW.

Minor pests

Thrips

Thrips including the tobacco thrip(also known as cotton

seedling or onion thrip),tomato thrip, and western flower

thrip are common early seedling pests but their damage is

usually cosmetic and rarely affects yield or earliness of

cotton.

Figure. thrip

Damage

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Nymphs and adults cause early season damage to terminals,

leaves, buds and stems. Infestations are more serious in cool

dry conditions when seedlings are unable to grow away from

damage. Severe damage results in destruction of the growing

point (tipping out) which leads to lateral branching. Seedling

death can occur due to severe infestation but this is often

associated with damping off diseases.

While considered a pest, thrips also predate on spider mite

eggs. In recent seasons western flower thrips have been

abundant on terminal growth later in the season.

Figure. damage of thrips in cotton


Sample weekly from emergence until the crop has six true

leaves for number of thrips/plant, checking for both nymphs

and adults (presence of nymphs indicates that the population

is actively breeding). Check the number of thrips on 20-

30 plants for every 50 ha of crop. Look for symptoms of tip

damage which appear as extensive blackening of the small

leaves within the terminal. Adults are highly mobile and

nymphs are very small so counts may vary with the time of day.

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The damage potential also varies with crop vigour and

temperature.

For seedlings to six true leaves the threshold is 80%

reduction in leaf area and 10 thrips/plant (adults and

nymphs). Thresholds may need to be lowered in adverse

conditions such as cold weather, herbicide damage and damping

off disease.

Management

• Consider that thrips are natural enemies of spider

mites. Use chemical control only if thrips damage

exceeds the threshold.

• Cotton crops planted next to cereal crops are more at

risk of thrips infestations.

• Thrips prefer cooler temperatures and populations

decline if temperatures rise above 30ºC.

• Western flower thrips are resistant to some insecticide

groups.

Predators of thrips include pirate bug, lacewing larvae, brown

lacewing and ladybird beetle.

Sucking bugs

Green vegetable bug (Nezara viridula)

Green vegetable bug(GVB)is an emerging pest of cotton. In the

past, sprays applied for other pests have also controlled GVB,

however the adoption of genetically modified cotton and

greater implementation of IPM has resulted in reduced

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insecticide use and GVB populations are increasingly found in

cotton crops.

The crop is most susceptible to damage from flowering onwards.

Both nymphs and adults cause damage to bolls. External damage

is visible through feeding marks and internal damage shows up

as wart-like growths and lint staining. Damage to bolls older

than 18 days is uncommon with the preferred age about 12 days

and less.


Crops should be inspected for GVB twice weekly in early to

mid-morning from boll set to boll maturity.Beat sheet

sampling is the most efficient monitoring method

as infestations tend to be patchy. Monitor as many sections of

the field as practical. GVB nymphs are more difficult to

sample accurately as their distribution is extremely clumped,

particularly during the early nymphal stages. Regular damage

assessment from boll set to boll maturity is recommended -

randomly select 14 day old bolls and look for the presence of

warts or stained lint. Damage symptoms cannot be distinguished

from those caused by mirids.

Thresholds depend on the sampling methods used:

• Visual sampling: 0.5 adults/m from flowering to harvest.

• Beat sheet sampling: 1 adult/m from flowering to harvest.

• Boll damage (14 day old bolls): 20% damage.

Nymphs of the GVB are less damaging than adults and their

numbers must be converted to adult covalents.

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Natural enemies

GVB eggs are frequently parasitised by a tiny introduced wasp,

the green vegetable bug egg parasite(Trissolcus basalis).

Parasitised eggs are easily recognised as they turn black. GVB

nymphs are attacked by ants, spiders and predatory bugs. Final

(fifth) instar and adult GVB are parasitised by the recently

introduced tachinid fly (Trichopoda giacomellii).

Pale cotton stainer bug (Dysdercus sidae)

Pale cotton stainer bugs generally arrive in cotton around the

time of first open boll. Adults mate soon after

arrival resultng in an expanding population of developing

nymphs. Cotton stainers are recognised as occasional pests of

cotton, but rarely cause economic damage and are often

controlled by broad-spectrum insecticides applied for other

pests. They cannot survive in temperatures above 40°C and need

free water for survival. In mild seasons they may need to be

managed especially in genetically modified cotton crops where

fewer insecticides are used.

Cotton stainers feed on developing and mature cotton seed,

resulting in loss of seed weight, oil content and seed

viability. Feeding on bolls up to two weeks old can kill

developing seed and cause boll shedding. Where bolls are not

shed, lint yield may be reduced and 'tightlock' around the

damaged seed prevents lint from fluffing out as bolls open.

Cotton stainers can continue feeding on seed throughout boll

development and also feed on the mature seed of open bolls,

creating bald patches (less lint). Yellow staining on lint may

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be evidence of watery faeces as bugs feed in the open bolls.

Pale cotton stainer bug damage is similar to that of green

vegetable bugs and includes a black spot on the outside of the

boll, warty growths inside the boll and brown discoloured lint

Monitoring

Beat sheet sampling is a suitable method to monitor bugs but

visual searching in the lower canopy compliments monitoring

methods. Sample at multiple sites as distribution is often

patchy. Stainer bugs tend to hide in the heat of the day and

are not easily observed at this time.

First instars are usually found on the soil or in the lower

canopy and tend to remain in clusters. Older nymphs can be

found in the lower to mid canopy and can be seen feeding in

open bolls. Once stainer presence is confirmed, monitor bolls

for signs of damage by cutting open bolls of varying ages to

confirm damage.

Natural enemies

The role of natural enemies of pale cotton stainer bugs has

not been studied in Australia. Natural enemies such as

tachinid flies (parasitic flies) and predatory bugs such as

assassin bugs have been reported in Africa.

Cotton harlequin bug (Tectocoris diophthalmus)

The cotton harlequin bug(also known as hibiscus harlequin bug)

feeds on many species belonging to the hibiscus plant family

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(Malvaceae), including ornamental hibiscus species and cotton.

It is sometimes a minor pest of cotton, feeding mostly on

young shoots, piercing the stems and sucking the sugar-rich

juices intended for shoot growth.

It has been known to cause the introduction of a fungus, which

rots the cotton boll. Nymphs feed on seeds in very small bolls

or in opening bolls. Generally damage occurs only in autumn.

Wireworms

Wireworms are larval stages of beetles that live in the soil

and generally feed on organic matter.True wireworms(Agrypnus

variabilis) prefer wet soil whereas the eastern false wireworm

(Pterohelaeus darlingensis) prefers drier conditions protected by

stubble and weeds.

Wireworms generally cause problems in spring especially in

newly developed fields, fallowed fields (with heavy trash

cover) and in fields following summer crops such as

soybeans. They bore into germinating seeds and chew through

young seedlings just below the soil level. Damage can occur

for up to four weeks after planting and heavy infestation

results in patchy stands that may need replanting.

Wireworms are difficult to sample as they move into the soil

when dry and only emerge after rain or irrigation, and

seedling damage is often the first indication of their

presence. Control measures must be applied before ors at

sowing. The most effective control is achieved by modern seed

dressings. In furrow bands, application of granular or liquid

insecticides are also effective.

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Red shouldered leaf beetle (Monolepta australis)

Red shouldered leaf beetle is a very minor pest of cotton,

damage is not common and usually confined to the edges of

fields. Larvae feed on plant roots while the adult beetle

chews terminal buds, leaves, squares and surface of bolls.

Leafhoppers (jassids)

Both the vegetable leafhopper (Austroasca viridigrisea) and cotton

leafhopper (Amrasca terraereginae) can affect cotton. Adult and

nymphs suck sap and inject toxins. Leafhoppers feed on the

upper surface of leaves. The damage appears as a pale stippled

effect. They occasionally damage seedlings and new growth.

Leafhoppers can transmit diseases such as viruses and

mycoplasma.

The current threshold for control through the early season is

50 leafhoppers per metre of row.

Minor caterpillar pests

A number of caterpillar pests can attack cotton plants. Most

of these pests are sporadic pests and rarely need control

unless large populations are present.Many caterpillar pests

use weeds as their main host plants before moving into cotton.

Control of these weeds will assist in minimising pest

infestation.

Rough bollworm (Earias huegeliana)

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Presence of rough bollworm in cotton is often associated with

the presence of the weed bladder ketmia, Hibiscus trionum. Direct

boll damage occurs when larvae tunnel into bolls. Larvae can

also be found in squares. Primary growing points can be

damaged by larvae tunnelling into the main stem. This can

occur at any growing stage including in seedlings.

The northern rough bollworm (Earias vittella) is of minor

importance in northern Australia, widely distributed

throughout Asia and is an important pest of cotton in India.

Cotton tipworm (Crocidosema plebejana)

Outbreaks of cotton tipworm are associated with winter and

spring rainfall and cool temperatures which favour growth of

Marshmallow weed Malva parviflora, the main host of tipworm. When

marshmallow dies off in early summer, tipworm move into

cotton.

Larvae tunnel into terminals destroying the single stem habit.

Subsequent multiple branching can lead to excess vegetative

growth at the expense of reproductive growth and crop

development can be delayed. At high numbers, squares and bolls

can be damaged.

Cotton looper (Anomis flava)

Loopers are leaf feeders. The cotton looper prefers older

leaves and defoliation of cotton progresses upwards on the

plant. Up to 80% defoliation has been recorded from large

infestations of cotton loopers.

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Pink spotted bollworm (Pectinophora scutigera)

The pink spotted bollworm is present in Central Queensland.

Larvae tunnel into large squares, flowers and bolls and often

complete their lifecycle within the one structure. Mature

larvae can also pupate on surface thrash and effective burial

of cotton crop residues reduces subsequent infestations.

The pink bollworm (Pectinophora gossypiella) is a major pest

overseas but currently restricted to north western Australia.

It could cause serious damage if it spread to eastern

Australian cotton regions.

Light brown apple moth (Epiphyas postvittana)

The host range of light brown apple moth includes many

broadleaf weeds as well as lucerne. It can be found infesting

cotton seedlings in cool seasons. Young larvae feed by tying

terminal leaves together with webbing.

Cotton leaf perforator (Bucculatrix gossypii)

Young larvae of the cotton leaf predator (first to third

instar) feed between the upper and lower leaf surface (mine)

while the fourth instar feeds directly on the leaf. The fifth

instar causes the most obvious damage by feeding on the lower

surface, leaving windows and holes in the leaf.

Cluster caterpillar (Spodoptera litura)

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Cluster caterpillar was a serious pest in Northern Australia

cotton growing areas but it is a minor pest in Queensland and

New South Wales. Young larvae skeletonise leaves at night;

larger caterpillars consume whole leaves. Caterpillars can

also destroy squares and flowers. Large infestations can lead

to larger areas being defoliated.

Lesser armyworm (Spodoptera exigua)

While often present in low numbers in young cotton, lesser

armyworm generally prefers weed hosts. Large numbers can cause

heavy losses in seedling crops by defoliating plants and re-

sowing may be necessary. Mature larvae can be mistaken

for Helicoverpa.

Cutworms (Agrotis spp.)

Cutworms attack cotton seedlings at or above ground soil

level. They feed in the late afternoon and at night, and can

destroy seedling by chewing through stems or eating entire

leaves.

Figure. Cutworm feeding damage

Summary & Conclusion

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Cotton, the “white gold” is one of the important commercial

crops playing a key role in the economic and industrial role.

Cotton is a soft, fluffy staple fiber that grows in a boll, or

protective capsule, around the seeds of cotton plants of the

genus Gossypium The fiber is almost pure cellulose. There are

many pests that are reducing the production and quality of the

cotton and categorized as major pests and minor pests. The

major pests of cotton include helicoverpa, spider mites,

cotton aphid and whitefly and minor pests include thrips,

green vegetable bug, cotton stainer bug, wireworm , cotton

harlequin bug, leafhopper, red shouldered leaf beetle, cutworm

etc. In this article, the description about insects, damage

symptoms and management of insect pest was included.

References

Fenemore.P.G and Prakash A.2006 2nd edition, applied

entomology., New age international P limited, publishers.

New delhi, India.

GC, Y.D.2010. Scarabs of Nepal and their microbial control.

Scarabs of Nepalese Agriculture and Microbial Control.

Lambert Acad. Publishing,Germany.

Srivastava K. P.1993., A textbook of Applied Entomology.,

Kalyani publishers., New Delhi.

Thapa, R.B., and S. Tiwari, Practical Manual of Insect Pest

Management.

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Cotton Pest Management

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