DOENÇAS NAS PHOENIX CANARIENSIS DO FISHERMANS WHARF

1) Em Abril de 2005 chegaram ao Fishermans Wharf várias palmeiras da espécie Phoenix canariensis, transplantadas de Shunde (Shuntak), na China. As palmeiras foram colocadas emcaixas no pavimento, com cerca de 2.2 metros de largura por 2 metros de profundidade. Como as palmeiras eram plantadas em caixas, o solo onde as palmeiras estavam plantadas drenava para uma camada drenante, constituída por grevilha, e dai directamente para a água. Entre a camada o solo e a camada drenante existia uma folha de geotextil, para impedira entrada de solo na camada drenante.A altura das palmeiras, medida até ao ponto onde se iniciam as folhas, era de cerca de 6 metros.As raízes com alguma terra, vinham protegidas por turfa negra, e envolvidas por uma rede preta, tudo suportado e envolvido por um saco, em rede metálica tipo malhasol. As dimensões do saco eram de cerca de 1. 6 metros de lado por 1.2 a 1.4 metros de altura. 2 - Actualmente existem no Fishermans Wharf

14 palmeiras (zona de Miami) 4 palmeiras (zona centro) 10 palmeiras (zona de Veneza).

3.1 - Em meados de Julho de 2005 começaram a notar-se sinais de decaimento em duas palmeiras. Alguns dias depois esses sinais estendiam-se a 5 palmeiras, e no dia 1 de Agosto, a 9 palmeiras – 5 na zona de Miami, 2 na zona centro, e 2 na zona de Veneza,

3.2 - Os sinais de decaimento materializam-se das seguintes formas: 3.2.1 - As folhas perdem o seu hábito vertical, e inclinam-se no sentido da horizontal, acabando por morrer. Por vezes são as folhas mais novas, do eixo central – as que deveriam ser as mais vivas – que apresentam este problema.

1

3.2.2 - Além disso um outro problema se verifica, materializado em manchas acastanhadas ao longo da nervura principal das folhas. Estas manchas, espalhando-se provocam também a morte da folha. Não é claro se estes dois problemassão distintos, ou se se trata de um problema ùnico, embora me incline para a primeira hipótese (os dois problemas são distintos).

4.1 - Estes problemas não derivam, pelo menos directamente,ou unicamente, da transplantação. Se derivassem quase todas as plantas estariam na mesma condição, o que não é o caso. Ainclinação das folhas significa que uma zona do eixo ou nervura central, junto ao ponto de inserção desse eixo ou nervura central com o tronco, perdeu a força, ou seja, sofreu um ataque. Além disso as folhas começam a inclinar-seainda verdes, o que significa que o problema não deriva da falta de água, isto é, não deriva – directamente, pelo menos, como se disse - da transplantação.

4.2 – Observando a 2 de Agosto, folhas doentes de 3 das árvores mais afectadas ( as folhas foram cortadas com o apoio do jardineiro que está dando apoio ao empreendimento, e de uma viatura elevatória emprestada pela empresa Sanderson) encontramos:

4.2.1 – Fungos: nas referidas manchas castanhas ao longo da nervura principal. Órgãos de frutificação desses fungos saiam do interior das folhas já cortadas (um sintoma nada bom, pois significa uma doença implantada dentro da palmeira) (ver fotos 1 e 2); -Nota: as partes castanhas estão mortas, as amareladas são a zona de ataque dos fungos,e as partes verdes estão vivas

2

3

4

4.2.2 – Podridão total do eixo central de uma palmeira (ver foto 3 );

4.2.3 – Manchas amareladas no eixo central de uma outra palmeira – a que apresentava as folhas do eixo central inclinadas (possivelmente a mesma doença de 4.2.2, mas num estádio menos avançado) (ver foto 4);

5

4.2.4 - Um micélio esbranquiçado envolvendo algumas folhas já cortadas, não sendo entretanto possivel saber se se tratade uma infecção primária ou oportunista, isto é, que ataca orgãos já mortos.

4.3 – Insectos: Numa das palmeiras mais atacadas encontramosfolhas com a base furada por insectos tipo “ gorgulho”(ver fotos 5 e 6 )

6

7

assim como três casulos desse animal, os quais se encontravam no interior dos eixos das folhas que estavam furadas; encontramos também um insecto(ver foto 7).

4.4 – Doenças semelhantes a estas, atacando palmeiras que foram transplantadas, são indicadas na obra Palms, de Alan W.Meerow, ed. Betrock, Holywood, Florida, 2002.

5 - Pelo exposto sugere-se:

5.1- Uma substituição dos elementos afectados; 5.2 – Um tratamento anti-fungos, com fungicida sistémico, tipo Benlate;5.3 - Um tratamento anti-gorgulhos deve ser também efectuado, com insecticida sistémico, p. ex. Malathion;5.4 - A continuação do estudo das causas do decaimento das árvores, pois de outra forma as novas árvores podem vir a sofrer exactamente dos mesmos problemas que sofrem as actuais.

8

6 – Sendo as árvores elementos vivos, o comportamento futuroé de dificil previsão, sendo entretanto a situação de certa gravidade, como aliás se comprova pela rapidez com que as árvores foram afectadas. Por outro lado há razoável probalidade que mais árvores venham a ser atacadas por estasdoenças.

Macau, 3 de Agosto de 2005

António Manuel de Paula Saraiva Engo. Agrónomo

9

Fusarium wilt:A host specific fungus of the palms, attacksprimarily Canary Island Palm. Infects through roots, long lasting in the soil. Damage:  Yellowing and death of fronds, often older fronds on one side first. Cutting into infected wood may reveal tissue has turned brown. Control:  Avoid injuring living tissue, Practice proper cultural care (avoid stress to plant), Avoid undecayed amendments and excessive fertilizer.

Pests  Palmetto weevils, palm leaf skeletonizer

  Diseases Lethal yellowing; magnesium deficiency; ganoderma; stigmina leaf spot, graphiola, phytophthora bud rot, fusarium wilt

Florida HorticultureDepartment of Ornamental Horticulture Fact Sheet

Florida Cooperative Extension Service Institute of Food andAgricultural Sciences

University of Florida, Gainesville John T. Woeste, Dean forExtension

LETHAL YELLOWING OF PALM TREESIN FLORIDAHenry Donselman*

Lethal yellowing (LY), a relatively new disease to Florida, has been recognized by other names in various Caribbean islands for close to 100 years. Jamaica's "west end bud rot," which appeared in the 1890's was a typical example. A small percentage of Jamaica's coconut palms was initially infected. The disease was not considered a serious problem until the 1950's when it began to spread rapidly in Jamaica and the Florida Keys. Because of Jamaica's economic

10

dependence on the coconut, immediate steps had to be taken. In Florida, the Division of Plant Industry and the University of Florida cooperated in efforts to attempt to eradicate the disease.

As with any new disease, early research efforts focused on the cause. Areas investigated included fertilization and nutrition, fungi, bacteria, insects (weevils, borers, etc.) and nematodes. Initially a virus was thought to cause LY as no other disease causing agent could be discovered. Applications of fertilizers, fungicides, bactericides, and insecticides failed to control the disease. In Key West, 75%of the coconut palms were destroyed. Research from 1955-1965demonstrated that LY was not a disease whose mysteries were going to be unraveled easily.

Spread of Lethal Yellowing

Little attention was given to LY in Florida during the 1960's as the disease gradually died out in Key West. In 1969 LY appeared in Key Largo and in late 1971 several treesin Coral Gables were diagnosed as having LY. Within months the disease had killed a thousand trees in Miami. In 1972, LY was reported in Broward County, and in Collier and MartinCounties during 1974.

Lethal yellowing is found in most of the Florida areas wherecoconuts can be grown. There is a possibility for LY to spread outside the range of coconut palms. A disease that affected thousands of date palms (Phoenix canariensis and P. dactylifera) in southern Texas in 1979 is now thought to be thesame as LY in Florida. Evidence to support this includes identical symptoms in Texas and Florida date palms, the presence of mycoplasma-like organisms, and the presence in Texas of a species of insect which has been shown to be a carrier (vector) in Florida.

Symptoms in Coconut Palms

Lethal yellowing may easily be confused with other yellowingand defoliating maladies of coconut palms, including fungal

11

bud rot, nutrient deficiencies and insect, nematode or lightning damage. Observations over the years, however, haveled to the recognition of four symptom stages for LY in coconut palms.

The first symptom is premature dropping of most or all coconuts, regardless of size. This is termed "shelling" and most of the fallen nuts will have a brown or black water-soaked area immediately under the calyx.

The second stage, usually definitive for LY, is the blackening of new inflorescences (flower stalks). This may be observed as they break through the spathe (the structure which enclosed the inflorescence) and is quite distinctive because healthy inflorescences are golden or creamy yellow. Most male flowers will be dead on the blackened inflorescences and no fruits will set.

In the third symptom stage, from which the disease gets is name, the fronds turn yellow, usually beginning with the oldest fronds and advancing upward through the crown. In some cases, one single frond in the center will turn yellow first giving a characteristic "flag" appearance. Fronds thathave yellowed will die, turn brown and hang down. Such fronds fall readily, or are easily pulled off.

Death of the bud occurs about halfway through the yellowing sequence. The newly emerged spear leaf will collapse and maybe seen hanging down within the crown. Finally the top of the tree falls away leaving a bare trunk or "telephone pole". Infected trees usually die within 3-6 months after appearance of the first symptoms.

Recognition of symptoms of the LY-like disease in other palms is more difficult. The first two symptom stages are the same as for the coconut palm-the premature dropping of fruit (shelling), and the blackening or necrosis of the new inflorescence.

12

The third symptom, in many cases the first obvious sign of adisorder, is discoloration of the fronds. At this stage of the infection the symptoms differ for individual species.

In general, frond discoloration due to LY falls into two distinct categories: those in which the fronds turn a golden-yellow before dying, and those in which the fronds turn a greyish-brown. Palms in the first symptom category, in addition to coconut palms, are talipot palms, two speciesof pritchardia, arikury, windmill, princess, and spindle palms.

In these palms, yellowing of the lower fronds is typical, but often one frond will turn before any others, giving a "flagging" appearance. The fronds remain yellow for various lengths of time before turning brown and dying. The fronds tend to break at the leaf base junction and hang down like acollapsed umbrella. Fronds may cling to the tree instead of falling to the ground.

The yellowing usually advances from the older to the youngerfronds with the spear leaf being the last to turn yellow. Once the spear leaf shows symptoms, the crown dies, the top of the tree falls away, and only a topless trunk remains.

The remaining susceptible palms fall into the second symptomcategory, browning or drying out of fronds. The Christmas palm, or adonidia (Veitchia merrilli) is perhaps the best exampleof this group. The first two symptom stages in these palms are also similar to those in LY-infected coconut palms. Frond discoloration is not as dramatic or easily detected inthe early stages as in coconut or pritchardia palms.

First evidence of infection is a brownish "water mark" alongthe margin of the pinnae or leaflets. Browning gradually extends to the entire frond giving it a dried out appearance. Older leaves tend to break easily at the junction of the leaf-base and midrib and younger fronds tendto break within the lower region of the pinnae. Unopened inflorescences may have a distorted or twisted appearance.

13

Death of the bud follows and the entire top falls away leaving a bare trunk.

The borassus, cabada, cluster, fish-tail, and the three species of Phoenix palms all show "browning" symptoms similar to those described for the Christmas palm.

Lethal Yellowing Research

The University of Florida Agricultural Research and Education Center in Ft. Lauderdale has beeen conducting LY research since 1972. In 1976 the effort increased as the impact of the disease on south Florida was recognized. This research and studies in Jamaica and Africa have brought a better understanding of the disease. The following points highlight these results:

A. Causal Agent of LY

In 1968, organisms called mycoplasmas were found to cause certain plant diseases. Many diseases previously thought to be caused by viruses have since been found to be associated with mycoplasmas or mycoplasma-like-organisms (MLO's). Evidence suggesting that LY was also caused by these single-celled organisms was reported in 1972. The presence of MLO'swithin the food-conducting tissues (phloem) of palm trees affected by LY and the response of palm trees to anitibioticinjections (oxytetracycline) were the two pieces of evidencewhich indicate that MLO's are responsible for LY.

B. Insect Vector

A planthopper identified as Myndus crudus has been shown to transmit the causal agent of LY in replicated tests at the Agricultural Research and Education Center. Myndus crudus wascollected from the leaves of palms where LY was prevelant and then transferred to caged, healthy palms. In all cages where the insects were introduced, the palms developed LY. The presence of the MLO was subsequently verified with the electron microscope.

C. Vector Control14

Insecticides slow the spread of LY, but they were not found sufficiently effective to warrant use in the field. Also, potential health and environmental effects of many insecticides in an urban area preclude broad use on tall coconut palms. Biological methods of controlling the vector are being investigated.

D. Culture of Mycoplasmas

Because plant mycoplasmas require precise conditions and a living host for reproduction, new methods are being exploredto allow rapid multiplication of MLO's for research use. Related mycoplasmas have been cultured using a new techniqueinvolving growth in an alternate host. Because of the size of palm trees, the number of years required to grow the trees, and the long incubation period of the disease (6 months to 2 years), a model system has been developed using Aster Yellows, a disease similar to LY that affects herbaceous plants. The mycoplasma that causes Aster Yellows can be isolated, introduced into the known vector, and re-transmitted to healthy plants. Much of the work done with Aster Yellows can be applied to LY research to speed up our understanding of the diseases associated with MLO's.

E. Spread of the Disease

Lethal yellowing has eliminated nearly all of the 'Jamaica Tall' coconut palms in Dade County, but some plantings of 'Jamaica Tall' had escaped the disease by 1981. Broward County has also lost most of its original coconut palms. Palm Beach County, largely because of the success of antibiotic injection programs, had lost only 35-40% of theircoconut palms by 1981. Replanting of resistant coconut varieties and the survival of some 'Jamaica Tall' palms haveall but restored the tropical atmosphere of the Florida Keys(Monroe County). The west coast of Florida still has most ofits 'Jamaica Tall' coconut palms but LY is a continuing threat to this area.

A lethal yellowing-like disease in Texas is killing thousands of Canary Island and some true date palms. This

15

points out the tremendous need for research on LY and raisesthe possibility that the disease may spread to the commercial date farms in California and elsewhere.

F. Other Palms Affected

Lethal yellowing also affects many other palm trees. Since 1972, 27 species of palms have been added to the LY susceptibility list. Many of these have commercial and ornamental value. Some species such as the Christmas palm (Veitchia merrilli), Fiji fan palm (Pritchardia pacifica), and Canary Island Date palm (Phoenix canariensis) are highly susceptible and it is recommended they not be planted until resistant selections are found. Other palms such as the Chinese fan palm (Livistona chinensis) and Cabada palm (Chrysalidocarpus cabadae) appear to be highly resistant and can still be used in the Florida landscape.

G. Antibiotic Control

Treating palms with oxytetracycline is effective in well-managed injection programs ( see Circular S-228, "How to Treat Your Palm With Antibiotic"). The University of Floridarecommends injecting only those coconut palm trees considered valuable to the landscape, and underplanting withresistant varieties for the future.

H. Palms Resistant To Lethal Yellowing

The long-range solution to LY is to develop or introduce resistant palms. To determine what makes a palm resistant a much better understanding of the disease is necessary. Hybrid coconut varieties such as the 'Maypan' are being planted in south Florida and their characteristics observed.Visual surveys of extensive existing palm collections in south Florida indicate that a number of species have potential as new introductions. Work in this area is being conducted both in the field and in a specially designed testgarden at the AREC, Fort Lauderdale.

What Can You Do?

16

To restore the tropical beauty lost to LY, a renewed programof replanting with resistant palm varieties must be undertaken. In the past, the only available coconut palm resistant to LY was the 'Malayan Dwarf'. The new hybrid 'Maypan' appears to require less care and grows more robustly than the commonly available 'Malayan Dwarf'. An increasing number of the horticulturally superior Green 'Malayan Dwarf' have become available. As with most ornamental plants, provide the best conditions at transplanting and a regular fertilization program for optimum growth.

Research is now underway to select new varieties of coconut palms and other palm species resistant to LY. Your county Extension office can suggest suitable palms already available from nurserymen.

*Henry Donselman is Assistant Professor and Extension Specialist, Lethal Yellowing; Department of Ornamental Horticulture, Institute of Food and Agricultural Sciences, University of Florida.

The author wishes to express his appreciation to the members of the Lethal Yellowing team: H.G.Basham, Assistant Professor, Physical Biochemist, F.W.Howard, Assistant Professor, Entomologist, R.E.McCoy, Associate Professor, Plant Pathologist; and J.H.Tsai, Associate Professor, Entomologist, for their assistance in preparing this publication.

This publication as promulgated at a cost of $984.00, or 8.2 cents per copy, to inform interested Florida residents about lethal yellowing of palm trees. 10-12M-81

florida plants online

Phytophthora bud  & root rotFact Sheet by Dr. Henry Donselman, Palm Specialist

    Phytophthora bud rot is common in Florida, Texas, California and other palm growing states, particularly on stressed palms.  This fungal disease can affect the roots of palms, especially if drainage is a problem or the soil stays overly wet.  More commonly, it is called a "Bud Rot" since often the visible sign we observe is the death of the newer emerging leaves.  Generally at this stage there is little that we can do, but drenches of the bud with Alliette have been curative when

17

the symptoms are not too far advanced.  A foul smell is often associatedwith the decaying palm tissue and secondary larval insects and worms areoften visible.

This disease almost always affects palms that are stressed for some other (generally horticultural) reason.  It is commonly seen in newly transplanted palms and is most severe in California in palms planted in poorly drained soils high in clay content.  For this and other reasons it is important to always make sure that drainage has been properly installed in new planting sites.

Dr. Alan Meerow has important information in Betrock's Guide to theLandscape Palms. (YOU SHOULD BUY THIS BOOK)

    Phytophthora bud rot is one of the more common diseases encountered in palms in wet tropical climates. It is primarily a warm season disease. This soilborne fungus causes collapse or brown-out of the younger foliage and emerging leaf. Discoloration of the internal tissue of the stem is evident, often accompanied by a foul smell. Phytophthora can also cause a leaf spot. Good control of bud rot is accomplished by drenching the soil with Banrot, or applying a foliar spray of Banrot or fosetyl aluminum (Alliette) at label rate. Foliar applied fosetyl aluminum will translocate to the roots of the palm, whereas Banrot will reduce populations of this soil-borne fungus in the root zone.  Overwatering and planting too deeply aggravate incidence's of Phytophthora.

Phytoplasma in Palm  

م�ا� ع�لى لاز وب� ت� ي� امراض� ال�فل ي� خ ال�ن

 

ي� ب! ال�عر Englishب�

ت� ص�فراز ال�ممي� Lethal yellowing (LY)الا,

مر ل ال�ت� ي� خ اء ع�لى ن� ض ي� مة� ال�ب6 Date palm white tip (BGWL)ال�ق�

18

ام ? Alwijamال�وج�

 

Fungi disease in Date Palm  

ة�� لامراض�ا ي@� طر ع�لى ال�فل ي� خ ال�ن

 

ي� ب! ال�عر EnglishScientificب�name

ع اوزاق� ق� ب ت��لة� �Kع ط�وب ق� (: ب� ) ال�سعف

ة� اوي�� مة� ال�ز ائ�, ق��

Leaf spot: rectangular pale brown spot

Alternaria alternate (Fr.)

نY ال�تXماز عف Fruit rotAlternaria alternateب��(Fr.)Aspergillus japonicus Asp. fumigatusAurobasidium sp. Botryodiplodia sp. Cladosporium sp.Nirgospora sp.  Paecillamyces sp. Fusarium lateritium F. moniliform Penicillium sp. Syncephalastrum sp.

ل ي� خ وزاق� ال�ن ت ا, ف� Xب Hole on dateت�\palm leaves

Alternaria sp.

19

مر ل ال�ت� ي� خ وز ن� ذ نY ج� Root rot ofع�فdate palm

Ceratocystis sp

ع اوزاق� ق� ب ت��ة� ي� ب ع ب� ق� (: ب� ) ال�سعف

لة� طي� م�سي�

Leaf spot: longitudinal brown spot

Cladosporium cladosporiodes (Pers.)

ل ي� خ وز ال�ن ثXراك�ت fgي Anthracnoseا,of date palm

Colletotrichum gloeosporioides Sacc.

واع�ذ الاوزاق� نY ق� عف ب��لودي� ي mال�ذت�

Diplodia leafbase rot

Diplodia phoenicum (Sacc.)

ع اوزاق� ق� ب ت��ع ق� (: ب� ة�   ) ال�سعف ي� ب ب�

رة� ث� غ ص�

Leaf spot: reddish brownparallel spot

Drechslera australiensis

وض ت� .BayoudFusarium oxysporum fال�ب6sp. albedinis Malencon

ازمى� وز ت� ول ال�ف Kب Fusarium wiltFusarium oxysporumال�ذSchlect

اع�ذة� ال�ساق� نY ق�� Basal stemع�فrot

Ganoderma zonatum MurrillG. boninese orG. tornatum Brisad

ع الاوزاق� ق� ب ت��ولي� ت� ال�ج راف�

Graphiola leaf spot

Graphiola phoenicis (Moug.)

ل ي� خ نY ط�لع ال�ن ع�فاس ال�طلع( ي� ) مرض خ�

Inflorescencerot

Mauginiella scaettae Cav.

20

ع اوزاق� ق� ب ت��ة� ي� ب ع ب� ق� (: ب� ) ال�سعف

رة� ث� ك�ب6

Leaf spot: brown leaf spot

Mycosphaerella tassiana (Johns)

الي� وم�ف وز الا, ذ نY ال�ج عف Omphalia rootب��rot

Omphalia tralucida BlissO. pigmentata Bliss

ا ع�لى ي� Xال�وش� سي� ع ال�ب ق� ب ت��ل ي� خ وزاق� ال�ن ا,

Pestalotia leaf spot

Pestalotiopsis palmarum Steyaer

لعات� Belaatمرض ال�يDisease

Phytophthora sp.

ل ي� خ وزاق� ال�ن حة� ا, Rachis blightل�فon leaves

Seronomyces phoenicis S. virginiae S. californicusS. sheari

حة� ال�سوداء نY(ال�لف عف ب��) ة� ام�ي� مة� ال�ي ال�ق�

Black scorchThielaviopsis paradoxa Hohn.

 

Insects

21

attack Date Palm Insects a

 

22

ttack florescence & date 

Enب�23

العر ب�ى�

glish

سو

س ة�

طلع

ال

ن

Inflorescence weevil

Derelomus

24

خن�

لدود ة�

ال

نلح

الص

عر

ي�

Lesser date moth

Batrachedra amydraula

25

دود ة�

ال

نلح

الك

نر

ي�

Greater date moth

Arenipses sabella

 Almon

Cadra cautella

26

d moth

 Indian meal moth

Plodia interpunctella

ا ب�ودق��ن�

Pomegranate

Virachola livia

27

ق�

الرما

Yن

fruit butterfly

 Saw-toothed grain be

Oryzaephilus surinamensis

28

etle

ج�نف

سا

ء ب�

وي�

ال

نلح

Date seed beetle

Coccotrypes dactyliperda

Reدd

Vespa orientalis

29

ب�و

ز

الا

جمر

wasp

 Insects atta

30

ck leaves  

ب�العر ب�ى�

English

FrPhonapate frontalisج

31

فا

ز

سعف

ال

نخن�

ل

ond borer

جXس

ر ة�

ا

Parlatoria

Parlatoria blanchardii

32

لنخن�

ل

ال

ف�Xس

رب�� ة� ب�ا

زل

ن�و

date scale

33

زب��اال

نق�

الذق��ن�ف�

ى�

Mealy Bugs

Maconellicoccus hirsutus

دو ب�ا

Date pal

Ommatssus binotatus

34

س

ال

نخن�

ل

m dubas

ج�راد

الصخ

راو

Desert Locusts

Schistocerca gergaria

35

ي�   Insects attacking roots & tru

36

nk 

ب�العر ب�ى�

English

ال

نم

ل

ال

Termites

Microcerotermes diversusMicrotermes najdensis

37

ا ب�ن�ض

كل

ت

ال

نخ

ر

The mole cricket

Gryllotalpa gryllotalpa

جف

از

س

The longho

Pseudophilus testaceus

38

اق�

ال

نخن�

ل د

و

ال

ف�روYن

ا

rn date palm stem borer

39

لط

وب��

لة�

جف

از

ع

ذوق�

ال

نخ

Fruit stalk borer

Oryctes elegansO. agamemnonO. boas

40

ن�لس

وس

ة�ال

نخن�

ل

ال

خمرا

Red palm weevil

Rhynchophorus ferrugineus

41

ءج�نف

سا

ء

ال

ف�لف

Bark beetle

Xyleborus perforans

 Insects

42

attack storage date  

Scient

Englis

43

ific name

h

Oilgonychus afrassiaticu

Old world date mite

44

s (Mc Gregor

Ephestia cautella Walke

Almond moth

45

r

Ephestia calidella Gunee   

Currant moth

Ephest

Grape

46

ia figulilella Gregson

moth

Oryzaephilus

Saw-toothed g

47

surinamensis L

.

rain beetle

Carpophilus dimidia

Dried fruit beetle

48

tus (Fab)

Tribolium confusum Duval

Confused flour beetle

 49

Nematodedisease ofdatepalm 

ب�العر ب�ى�

English

50

ب��عف�

ذ

ال

خذ

وز

ال

نن�

ماب��

و

Root knot nematodes

Meloidogyne spp. M. incognita M. javanica

51

دي�

ب��ن�

ماب��

ودا ب��ف�

رح

ال

خذ

 Pratylenchus spp.

52

وز

  Helicotylenchus spp.

ب��ن�

ماب��

ودا ب��ف�ر

م

ال

 Tylenchorhynchus spp.

53

خذ

وز

  Hoplolaimus spp.

  Hemicriconemoides spp.

  Macroposthonia spp.

  Paratylenchus spp.

  Hemicycliophora spp.

ب��ن�

ماب��

ود

 Trichodorus spp.

54

ا ب��ف�

صف

ال

خذ

وز

  Longidoruse spp.

  Xiphinema spp.

  Tylenchus spp.

 

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DatePhoenix dactylifera Pests and Diseases

Unripe fruits are attacked by Coccotrypes daclyliperda which makesthem fall prematurely. Ripe fruits are often infested by nitidulids—Carpophilus hemipterus, C. multilatus (C. dimidiatus), Urophorus humeralis, and Heptoncus luteolus, which cause decay. Control by insecticides is necessary to avoid serious losses. In Israel, the fruit clusters are covered with netting to protect them from such pests as Vespa orientalis, Cadra figulilella and Arenipes sabella as well as from depredations bylizards and birds.

In Pakistan, the red weevil, or Indian palm weevil, Rhynchophorus ferrugineus, bores into the leaf bases at the top of the trunk, causing the entire crown to wither and die. The rhinocereus beetle, or black palm beetle, Oryctes rhinocerus, occasionally attacks the date. Its feeding damage may provide entrance-ways for the weevil. Scale insects may infest the leaves and the trunk. They have been controlled by trimming off the heavily infested leaves, spraying the remaining ones, and treating the fire resistant trunk with ablowtorch. Two of the most destructive scales are the Marlatt scale, Phoenicoccus marlatti; which attacks the thick leaf bases, and the Parlatoria scale, Parlatoria blanchardii, which is active in summer. The latter was the object of an eradication campaign in California and Arizona in the late 1930's. The date mite scars the fruits while they are still green.

A tineid moth and a beetle, Lasioderma testacea, have damaged stored dates in the Punjab. Dates held in storage are subject to invasion by the fig-moth, Ephestia cautella, and the Indian meal-moth, Plodia interpunctella.

Fusarium albedinis causes the disastrous Bayoud, or Baioudh, disease in Morocco and Algeria. It is evidenced by a

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progressive fading and wilting of the leaves. Over a 9-year study period of 26 resistant varieties in Morocco, Bayoud disease reduced the planting density from 364 palms per acre(900/ha) to 121 to 142 per acre (300-350/ha). It is because of this disease that 'Medjool' can no longer be grown commercially in Morocco and Algeria.

Decay of the inflorescence is caused by Manginiella scaeltae in humid seasons. Several brown stains will be seen on the unopened spathe and the pedicels of the opened cluster will be coated with white "down". Palm leaf pustule, small, dark-brown or black cylindrical eruptions exoding yellow spores, resulting from infestation by the fungus Graphiola phoenicis, iswidespread but often a serious problem in Egypt. Date palm decline may be physiological or the result of a species of the fungus genus Omphalia. Diplodia disease is a fungus manifestation on leafstalks and offshoots and it may kill the latter if not controlled. The fungus caused condition called "black scorch" stunts, distorts and blackens leaves and adjacent inflorescences. Other fungus diseases include pinhead spot (Diderma effusum), gray blight (Pestalotia palmarum) and spongy white rot (Polyporus adustus). The date, as well as its relative, Phoenix canariensis Hort. ex Chaub., has shown susceptibility to lethal yellowing in Florida and Texas. No commercial plantings have been affected.

Palm Tree

I N S E C T S 

Cabbage Palm CaterpillarCabbage palm caterpillars, found throughout Florida, target the cabbage palmetto almost exclusively. They rarely kill palm trees but the insects do destroy the trees' blossoms. They are a nuisance to humans as well because they often enter homes looking for suitable places to pupate. Control by insecticides is possible under certain circumstance if carefully managed.

 

Giant Palm BorerThe borer is a large and quite ugly beetle whose larvae have a taste for the wood of the Washingtonia and Phoenix varieties. Borer grubs can live inside a palm trunk for up to nine years before exiting as beetles through quarter-sized holes.

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Palm BudwormThe budworm is beetle whose larvae feed on the flowers of a range of fan palms. The caterpillars are about an inch long and a pinky-green in colour.

 

Palmetto WeevilThe Palmetto Weevil can be found throughout Florida, as far west as southern Texas and as far north as South Carolina. It is North America's largest weevil. This pest has a taste primarily for the Cabbage Palm (sabal palmetto) although it will infest Saw Palmettos (serrenoa repens) and, occasionally, Canary Island Date Palms (phoenix canariensis), Washington Palms (washingtonia), Royal Palms (roystonea), and some coconut palms.

 

Royal Palm BugThe Royal Palm Bug is an unusual insect. It feeds on only one plant, the royal palm, and the female lays one egg a day during the spring, a little like a chicken. The bugs rarely kill the host tree but the damage they do can be unsightly and they are difficult to control given the height of mature royal palms. These insects are the only North American members of the Thaumastocoridae family.

 

ThripsNorth America's thrips make up an extremely large family of insects. Of the plant feeders alone, there are 264 species. And some of these species have a taste for palm trees, feeding on flowers and leaves by puncturing the surfaces to suck out sap. Thrips are not lethal to palms but the feeding of the adults can discolor and wilt leaves. In addition, in intensive infestations their unsightly black droppings can become noticeable on leaf surfaces.

 

D I S E A S E S

Bud RotBud rot is caused by a fungus which causes the heart fronds of a palm tree to wilt and die. Tree death can occur soon afterward. California and Mexican palms are the most vulnerable.

 

Fusarium WiltFusarium wilt is another palm tree fungus. Signs of wilt are fronds wilting, losing their green luster and, finally, dying. Once a tree is infected, there is no cure and the diseased tree may have to be removed.

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Ganoderma Butt RotGanoderma butt rot is a relatively new and lethal disease of Florida palm trees. It is caused by a fungus,

 

Lethal YellowingLethal yellowing is a disease first noticed in the Caribbean region of North America about 100 years ago. However, it was not until the 1950s and a devastating outbreak in Jamaica and the Florida Keys that the economic consequences of lethal yellowing were recognized and intensive research begun.

 

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