Pertanika 4(1), 10-15 (1981)

Sypmtomatology of Tobacco Mosaic Virus (TMV) andChilli Veinal Mottle Virus (CVMV) on six local Chilli.

INON SULAIMAN and WEE NGO GIMDepartment of Plant Protection, Faculty of Agriculture, Universiti Pertanian, Serdang, Selangor, Malaysia.

Key words: Chilli (Capsicum annuum L.); Symptomatology; Tobacco mosaic virus (TMV)j Chilli veinalmottle virus (CVMV).

RINGKASAN

Suntikan tunggal dan campuran virus-virus tobacco m'Jsaic virus (TMV) dan chilli veinal 11l?ttlevirus (CVMV) deng~n cara mekanikal ~ilakukan k~ atas. a,nak benih ~nam cultivar cili yang berumur satubulan untuk kajian stmptom. Pokok ka]1an yang dtJangkttt oleh satu lsolate virus memperlihatkan simptomyang tersendiri, manalwl~ pokok-pokok yang dijangkiti oleh kedua isolate virus memperlihatkan kedua-duasimptom isolate yang terMat.

SUMMARY

Single and mixed inoculations of tobacco mosaic virus (TMV) and chilli veinal mottle virus (CV MV)were carried out mechanically on one month old see~lings of st~ local chilli cultivars to study symptomatology.Test seedlings singly infected expresse~ symptoms typical of the ISolate whereas mixed infection resulted in plantsshowing combined symptoms of both Isolates.

INTRODUCTION

Chilli (Capsicum sp.) is one of the mostpopular solanaceous fruit vegetables grown inMalaysia. Two species of chilli grown areCapsicum annuum L. and C. frutescens. Theformer is cultivated mainly on the lowland, whilethe latter on higher altitudes.

According to the Ministry of Agriculture(Annon, 1976) the total sole crop equivalentunder chilli cultivation was 931 hectares. Pro­duction of chilli cannot meet local demand andthus additional imports are necessary. Besideslow acreage, production of chilli in Malaysia isalso hampered by pests and diseases. Amongthe diseases, mosaic of chilli caused by virusesis mentioned to be common (Thompson andJohnston, 1953).

Mosaic disease of chilli was first reported inPeninsular Malaysia by Burnett (1947) and laterlisted by Thompson and Johnston (1953).Tobacco mosaic virus (TMV) and cucumbermosaic virus (CMV) were cited as the causalagents based on the symptoms observed, althoughno attempts were made to e3tablish their presencein the infected plants (Burnett, 1947). Ong

(1975) reported that the most widespread chillimosaic disease was that caused by chilli veinalmottle virus (CVMV) a member of the potyviru­group. Ong (1975) in his study of the symptomastolog~ of suscep.tible plants to CVMV mainlydcscnbed the fohar symptoms only. The objectof the present study is to elaborate on the~ym~toms.on tIle whole plant, except the roots,m smgle mfections and combined infections ofCVMV and TMV on six local cultivars of whichfive are common in Malaysia.

MATERIALS AND METHODS

The two virus isolates, TMV and CVMV,used in this study were obtained from the Malay­sian Agricultural Research and DevelopmentInstitute (MARDI), Serdang.

The glasshouse experiment was performedusing chilli cultivar CI0 obtained from MARDIand five other local chilli cultivars designated A,C, ~, E. ~nd F from the Agronomy Department,UmversltI Pertanian Malaysia. The six varietieswere treated with four types of treatments viz.;two single virus inoculations, a mixed virusinoculation and a control. Each treatment con-

Key to authors' names: Sulaiman, I. B. and Wee, N. G.

10

I. B. SULAIMAN AND N. G. WEE

sisted of three plants, replicated twice in a com­pletely randomized design.

Aphids and mites. were controlled by bi­weekly spraying of 0.01 % a.i. of Malathion orKelthane. At fruit maturity 0.1 % a.i. Manzate-Dspray was carried out biweekly to avoidanthracnose disease. Fertilization of the plantper pot was at the rate of 10 gm of Nitrophoskablue (R) for the first 2 months of growth and15 gm for the subsequent growth duration. Allplants were watered daily.

Chilli seeds were sowed on sterilised soil ina seeding box; and two weeks ~.fter germinationtransplanted into 10" diameter clay pots. Thesoil mixture used was composed of soil, peat andsand (3 :2:1) to one cubic yard, to which wereadded 5 lb lime and 5 lb Nitrophoska blue(R)during mixing.

The virus inoculations were performed whenthe seedlings were 30 days old. Innocula wereprepared by grinding TMV and CVMV infectedleaves of chilli cultivar CI0 separately in 0.5Mphosphate buffer pH. 7.0 and 0.5M phosphatebuffer pH. 7.0 containing 0.05M MgCI and 0.1 %sodium sulphite respectively. The ratIO ofdiseased leaves to buffer was 1:3 (WIV).

The crude sap was then applied separatelyon the ~.daxial surfaces of carborundum dustedleaves of the seedlings. In the mixed infectionstudy equal volumes of TMV and CVMV inoculawere mixed and applied in the same manner.The leaves were rinsed with water immcdiatleyafter inoculation. -

RESULTS AND DISCUSSION

The results of the symptomatology studiesare summarised in Table l(a) and l(b).

Foliar SymptomsLeaves of CVMV ~.nd TMV infected plants

exhibited varying degrees of vein clearing,mottling and chlorosis (Plate 1). However,CVMV infected plants did not develop leafpuckering and veinal necrosis and they alsoshowed various types of leaf distortions including;leaf epinasty, leaf narrowing, filiform leaves andirregularly shaped leaves. Ong (1975) alsoreported leaf distortions of CVMV infectedplants. Mixed infection of CVMV and TMYon chilli plants shows combined symptomscharacteristic of both CVMV and TMV (Plate 1).

Stem SymptomsMottling, swelling and lesions were three

types of stem symptoms observed in this study.

Plate 1: Foliar symptom showing varying degrees of chlorotic mottling induced by single and mixed virusinfection.

11

SYPMTOMATOLOGY OF TMV AND CVMV ON LOCAL CHILLI

TABLE lea)

Summary of the Symptomatology Studies - Symptoms are listed in order of their appearance.

Foliar Symptoms-------------------------------------------

Virus Cultivars Vein Leaf Distortions VeinalPuckering Clearing Mottling E N F I Tecrosis Chlorosis IP

CVMV C10 + ++ + + + + +A + + + + + +C + + + + + + 40 + ++ + + + + +E + ++ + + + +F + ++ + + + + +

TMV C10 + + + + +A + + + + +C + + + + + 20 + + ++ + +E + + ++ + +F + + ++ + +

CVMVand

TMV C10 + + + + + + + + +A + + + + + + + +C + + + + + + + + 2D + + ++ + + + + + +E + + ++ + + + + +F + + ++ + + + + + +

++ Severe Mottling F Filiform leaves

+ Mild Mottling I Irregularly shaped leavesE Leaf Epinasty IP Incubation Period (Days)N Leaf Narrowing + Present

Absent

TABLE 1(b)

Summary of the Symptomatology Studies - Symptoms are listed in order of their appearance.

Stem SymptomsFlower Fruit

Stem Stem Stem ISL Distortion SymptomsMottling Swelling Lesion a b

+ + + ++ + + ++ + + ++ + + ++ + + ++ + + +

Virus

CVMV

TMV

CVMVand

TMV

Cultivars

C10ACoEF

C10ACDEF

C10ACDEF

++++++

++++++

++

++

++

++

++++++

++++++

++++++++++++

a

+Light green stripe and mottlingPresentAbsent

12

bISL

Blacks marking on fully red fruits.Internal Stem Lesion

I. B. SULAIMAN AND N. G. WEE

The first two symptoms were only found onCVMV infected plants while stem lesions occurredon TMV infected cultivars E and F only. Mixedinfection produced characteristic symptoms ofboth viruses (Table l(b)).

Stem swelling was one of the characteristicsymptoms of CVMV. The swellings were foundmainly on the mainstern (t - 2/3 of the totallength). Some might also appeared on the upperbranches (Plate 2). Plants infected with mixedviruses showed smaller swellings. The swellingswere in the form of slight protrusions mainly onthe upper branches of all cultivars.

Stem lesions were observed on some cultivarsinfected by TMV as indicated in Table l(b)

Plate (3). Infected plants showed wilting signsfollowed by leaves dropping due to veinal necrosis.These plants recovered with the development ofnew shoots a week or two later.

Internal stem symptoms were manifest bythe necrotic pitting of the pith. In cases wherethe necrotic stem lesions were externally severe,the whole pith also became necrotic.

Various stem necroses of pepper caused byother viruses and by TMV have been reportedby other workers (Holmes, 1937; Doolittle andZaumeyer, 1952; Miller and Thornberry, 1958;Murakishi, 1960; Greenleaf et al., 1964).

Plate 2. Stem swelling characteristics of CVMVinfection on all six chilli cultivars.

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Plate 3. Stem lesion characteristics of TMVinfection on two chilli cultivars studied.

SYPMTOMATOLOGY OF TMV AND CVMV ON LOCAL CHILLI

Plate 4: Flower distorti'Jns induced by CVMV.

Flower Symptoms

Calyx deform~.tions and petal distortionsfrom irregular margins, curling tips, filiformshapes, unequal lengths and incomplete numberswere observed in plants infecttd by CVMV ormixed infection of CVMV and TMV (Plate 4).However, infection by TMV alone did not causeflower distortion.

Fruit Symptoms

Symptoms on fruit of CVMV infectedplants varied from distortions to various typesof colour deviations. Fruit distortions includtdsurface roughing, twisting and malformation ofvarious kinds. All fruits showed colour devia­tions such as a light green stripe (1 - 2 mm wide)along their length or mottling of varyingintensities. These became reddish brown ordirty brown 1 - 2 days before ripening butdisappeared totally when the fruits were fullyred.

Fruit distortions caused by TMV weresimilar to, but less severe, than those caused byCVMV. Half-ripe fruits possessed intermingledreddish brown and dirty glossy green colours.When fruit ripened, they showed irregular blackmarkings (Plate 5).

----------------------

Plate 5. Irregular black markings on fully redfruits due to TMV.

1. B. SULAlMAN AND N. G. WEE

CONCLUSION

The symptomatology studies showed thatall cultivars infected with CVMV producedsevere leaf distortions, stem mottling, stemswelling, flower distortions and colour deviationson immature fruits. In contrast, plants infectedby TMV showed transient puckering symptomson inoculated leaves, veinal necrosis, stem lesionson some cultivars and irregular black markingson ripened fruits. Mixed infected cultivarsproduced symptoms that were characteristic ofboth virus isolates.

ACKNOWLEDGEMENT

We wish to thank Mr. Ong Ching Ang ofMARDI, Serdang, for providing us with thetwo virus isolates, TMV and CVMV, and Dr.Halim Hassan for providing the five local chillicultivars,

REFERENCES

ANONYMOUS (1976): Statistical Digest. PeninsularMalaysia. Economic and Statistic Section. Minis­try of Agriculture. Kuala Lumpur.

BURNETT, F. (1947): Report on Agriculture in Malayafor the year. 1946. 85 p.

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DOOLITTLE, S.P. and ZAUMEYER, W.J. (1952): A ring­spot disease of pepper caused by strains ofcucumber mosaic virus from pepper and alfalfa.Phytopath. 43: 333-337.

GREENLEAF, W.H., COOK, A.A. and HEYN, A.N.J.(1964): Resistance to tobacco mosaic virus inCapsium with reference to Samsun latent strain.Phytopath. 54: 1367-1371.

HOLMES, F.O. (1937): Inheritance of resistance totobacco mosaic disease in the pepper. Phytopath.27: 637-642.

MILLER, P.M. and THORNBERRY, H.H. (1958): A newviral disease of tomato and pepper. Phytopath.48: 665-670.

MURAKISHI, H.H. (1960): A necrotic pod streak ofpepper caused by tobacco mosaic virus. Phytopath.50: 464-466.

ONG, C.A. (1975): Studies on a mosaic disease ofchilli (Capsicum allnuum L.) in Peninsular Malay­sia. M.Sc. Thesis. Universiti of Malaya KualaLumpur.

THOMPSON, A. and JOHNSTON, A. (1953): A host listof plant diseases in Malaya. Mycol. paper 52:38 pp. Commonwealth MycoJ. Inst. Kew. Surrey.

WEINBAUN, Z. and MILBRATH, G.M. (1976): Theisolation of tobacco etch virus from bell peppersand weeds in Southern Illinois. Pl. Dis. Rept,..60: 469-471.

(Received 1 October 1980)