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NEW DISEASESAFFECTING BLACK PEPPER CROP IN BRAZIL*

Maria de Lourdes Reis Duarte, Fernando Carneiro de Albuquerque', Elizabeth Ying Chu3

INTRODUCTION

The cropped area with black pepper inBrazil has increased greatly, due to theattractive prices in the international market.From 1999, the area under cultivationincreased 15% being the production estimatedin 30 to 35 metric tonnes, in 2001 (IPC ..2000).The State of Para is the main producercontributing with some 85% of pepperproduction, which come from Bragantina(Panniyur-l ecotype), Singapore (Kuchingecotype) and Guajarina (Arkulan Mundaecotype) culti vars. The Kottanadan-l andIaçara-l (ariginated from open pollination)have been cropped by many pepper growers inorder to enhance the genetic variation withinblack pepper population and to improve thecontent of essential oil, piperine, oleoresin ofthe final products.

In the past four years, black pepper plantshave been affected by new diseases other thanroot rot and stem blight (Nectria haematococcaf. sp. piperis). Even minor diseases likeanthracnose (Colletotrichum gloeosporioidesPenz) and black berry disease (Cephaleurosvirescens) have caused losses of productionunder special climate conditions. Descriptionsof the main symptoms, causal agent andcontrol measures are given.

YELLOWWILT

Since 1992 black pepper vines, cultivarGuajarina growing in the field for more thanfour years have been affected by a new disease,in the municipality of Tome Açu. After eightyears since the first record, this disease hasbeen noticed in the municipalities of Baião,Castanhal, Bujaru, São Francisco,Paragominas, lpixuna, Mocajuba, CapitãoPoço, Santarém Novo, Primavera, Vila daForquilha, Jamic and Tailândia

Symptoms

The pathogen invades pepper throughwounded roots inflicted by nematodes(Meloidogyne incognita and M. javanica) arduring the emergence of new roots. It colonisesthe vascular bundles causing necrosis andpreventing water and nutrients uptake. Thevascular necrosis, unilateral initially, extents tothe leaf veins of apical twigs resulting in quickwilt and death of plants. Externally, diseasedplants shows yellowing, shedding of leaves andinternodes and lack of rootlets (Fig. 1). Theinternodes show triangular and necrotic lesionsaround the nodes of the main branch, whichresult in unilateral necrosis of the internodeturn them half green half necrotic (Fig. 2).When several roots are infected, the plantcollapses getting the foliage adhered to thebranches. If branches are cut, necrotic vesselsof phloem can be seen immediately belowepidermis (Duarte et aI., 1999).

'Ph.D., Senior Seienlist, Plant Pathologist, Embrapa Amazônia Oriental, Tv. Dr. Eneas Pinheiro, s/no, CEP66095-100, Belém, Pa, Brazil e-mail: mlourdes@cpalu.embrapa.br'M.Se., Senior Researcher, Plant Pathologist, Embrapa Amazônia Oriental3M.Se., Researeher, Soil Microbiology, Embrapa Amazônia Oriental'Researeh partially supported by JICA suggesting that the pathogen is being spread by infeeted stem cuttings. Inlhe field this disease has been recorded so on Guajarina cultivar, so faro

* Paper presented in the 2ôh Peppertech Meeting of [PC, held at Belem, Para, Brasil, se: Oct. 2001

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The disease has been observed in pepperplantations that graw Guajarina cultivar, evenin properties in the same area where Bragantinaand Singapore are planted.

Causal agent

The disease is caused by Fusariumoxysporum Schlecht.:Fr. The pathogen wasisolated fram discoloured tissues of orthotrapicbranches. It produces floccose and sparsemycelium, ranging in colour fram white tolight violet. Numeraus and hyaline conidia arepraduced in the central part of the colony.Macraconidia are fale ate to almost straight,with thin walls measuring 12 um - 44 um x 4um - 8 um, with apical cells like a hook andthe basal is foot-shaped and formed frammonophialides on hyphae. Septum numbervaries fram 3 to 7, being more frequent 4-septaspores. Micraconidia are unicellular, ovoid toelliptic measuring 3.6 um - 9.6 um x 2.4 um- 6.0 um and formed on false heads on shortmonophiallids on hyphae. Chlamidospores areformed by the eighth day but after 30 days ofage most of mycelium and conidia are turnedinto globose and brawn and thick wallchlamidospores.

The pathogen was identified by Dr.Brayford fram Intemational MycologicalInstitute as Fusarium oxysporum, a newpathogenic formae to black pepper, whoseorigin is still unknown .

Hosts

In the field, the pathogen has beeninfecting Guajarina, cultivar of black pepper,but under experimental conditions, it has theability to infect vessel tissues of Bragantina,Iaçará-I and Singapore. The majority of blackpepper genotypes have shown intermediate andresistant responses.

Guajarina is an ecotype of ArkulanMunda intraduced in Brazil in 1976 andavailable to the pepper grawers since 1982. Ithas braad leaves and long spikes. Althoughsusceptible to Nectria haematococca Berk &Br. f. sp. piperis Albuq., it has been the peppergrawers preference due to its high praductivity(3.5 tonlha).

Recommended control measures

In Tomé Açu, some pepper grawers havebeen trying to prevent the disease spreadthraugh cultural practices as balanced fertiliserformulation with high content of ~O, covercrap with leguminous, dolomite lime.However, as a soil-borne pathogen thefollowing contrai measures are alsorecommended: a) Collect stem cutting framfree-disease pepper plants, only; b)Preventative treatment of stem cutting byimmersion in 0.1% benomyl solution for 15 to20 minutes, before plant; c) Suitable drenchingof cultivated area; d) Rouging of infectedplants followed by drench of 5 to 10 litres0.1% benomyl or thiabendazole solution in thepit. Surrounded plants should also to betreated; e) Keep area just cut-weed to restraindisease spread; f) Prevent soil depression("basins") around the base of pepper plantswhile cut weed; g) Apply fertiliser formulationwith increased ~O content; h) ReplaceGuajarina cultivar by Singapore, Bragantina(Panniyur-I ecotype) and Kottanadan-I thathave shown resistant response to the pathogencolonisation.

BLACK BERRY DISEASE

Pepper plantations have been affected byminor diseases as black berry disease known inBrazil as algae black spot that causes severedamages to berries in the main Asian praducercountries. In those areas it has been observedthat old and poor grawth pepper vines are moresusceptible.

Fram 1998 on, it has been noticed thatthis disease that for a long time was occurringendemically causing no serious losses topepper craps, began to cause epidemics in themunicipalities of Paragominas, Don Eliseu andTome Açu, State of Pará resulting in decreasesof praductivity.

Symptoms

The disease affects leaves, stems, andspikes. Young leaves show minute andnumeraus spots, which are black brilliant incolour, erumpent, with resinous appearanceand irregular margins, surrounded by a yellowhalo (Fig. 3). Discoloured veins embedded intoyellow halo can be seen. As numeraus blackspot are formed on young leaves, prematurefall of leaves may occur. Lesions are formed in

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between or on secondary veins being morecommon in between veins. Numerous and quitelong black depressed stripes are formed onyoung stems. On old stems, long and deprcssedlesions showing cracks in the central partreaching I to 2 mm depth are noticed (Duarteet al., 2000). Those cracking serve as entry toother fungi like Colletotrichum gloeosporioidesPenz & Nectria haematococca Berk & Br. f.sp. piperis Albuq. In the Municipality of DonEJiseu symptoms of dic-back and fali of leaveshave been observed in poor managed crops. Oninfected spikes the rotten fruits become Jightand are of low value for market.

Causal agent

The disease is caused by the algaCephaleuros virescens Kaunze, a plantpathogenic green algae (Chlorophyta) thatbelongs to the family Trentepholiaceae andoccur world-wide in tropical and subtropicalregions where the temperature and humidityconditions are suitablc (Joubert & Rijkenberg,1971). C. virescens is a phycobiont of twoparasitic Jichen species, Strigula camplanata(Fee) Mont. and S. elegans (Fee) Mull. Arg.,which also occur commonly but not recognisedas parasites (Holcomb, 1986). That alga is lheonly parasitic alga of superior plants with anample host range among cultivated and nativoplants of different botanical families. Thepathogen produces endophytic and discoidmycelium formed by articulate hyphae thatgive rise to erect and aerial hunches containingsporocysts. It has hlue and green cytoplasmand reproduces hy zoogonides or oogonia(Bicudo & Bicudo, 1970).

Epidemics of alga black spot are related tomist formation that lasts for four to five houron plants growing near forest, from Septemberto November, as average temperature reaehes27° C and relative humidity is around 77%.

HostsC. virescens is the incitam of leaf,

stem and fruit diseases of economicallyimportant tropical plants such as tca (Camelliasinensis (L.) O. Kuntze), coffee (Coffeaarabica L.), oil palm (Elaeis guineensis Jacq.)Jitehi (Litchi chinensis Sonn.), vanilla (Vanillaplanifolia Andr.), guava (Psidium guava L.),cacao (Theobroma cacao L.) and citrus (Citrusspp. ) (Wellman, 1972; Marllat & Alffieri,1980). Leaf spot damage to the majority of C.virescens hosts is of a minor nature and usually

limited to death of cells just beneath the algalthallus.

Recommended control measures

Due to the high incidence of the disease,measures of control are recommended mainlyin clonal gardens from where vegetativematerial to produce new plants are taken.Weekly or biweekly sprays of Benomyl at0.05% active ingredient after spike formationhave been effective as well as of Triadimefonor Triadimenol. Sprays with protectivefungicides like Mancozeb, Captan or Coppercompounds are also recommended to preventalgal resistance and to control other foliarpathogens

PIPER YELLOW MOTTLE VIRUS

Brazilian pepper plantations have beeninfected by several pathogens including fungi,alga, nematodes and viruses. Pepper mosaiccaused by a strain of Cucumber mosaic virus(CMV -Pn) was detected for the first time in1970 but, a prompt eradication of infectedplants prevented pepper production from acollapse. There are still some spots of thedisease in some municipaJities in the State ofPura but, the disease is under control, theincidence being Icss than 2%.

From October 1998, some black pepperplants showing symptoms of an unknowndisease were observed at Embrapa germplasmcollcction, in Belém, State of Pará. In leavesand branches samples sent to Virologylaboratory at São Paulo State University virusparticle associated to infected tissues weredetected. The origin of this disease is not clearbut there is a suspieion that it was introduced inBrazil in pepper accessions introduced fromIndia.

Symptoms

Infected plants show leaves with yellowand brilliant punctuation disperscd in foliarblade or interveinal forming a typical mott1e.Severely infected leaves are malformed withwaving margins (Fig. 4). Peppcr plants showchanges in its growth pattern. Foliage becomesparse, and decreases in production areobserved due to reductions in the size andnumber of berries per spike. After the branchesare cut new shoots show chlorotic and

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malformed leaves and delayed growth.Internally, vascular vessels show discolorationand necrotic points.

Causal agent

The disease is caused by Piper yellowmottle virus (PYMV), a non-envelopedbacilliform virus-like particle assemble tobadnavirus (Lockhart et aI., 1997). Theoccurrence of PYMV in several black peppercultivars (laçará-I, Karimunda, Guajarina,Bragantina, Apra, Kottanadan-2, accessions239 and 1558) was detected after ultrafinesections observed under scanning microscopeunder low frequency, in the mesophyllparenchyma cells, PCR tests confirmed virusidentity.

This disease has already been detected inIndonesia, Thailand, Sri Lanka and Malaysia(Lockhart et al., 1997). Pepper plants showingsimilar symptoms to those caused by PYMVwere noticed in India and Indoncsia (Holliday,(959).

Differential symptoms between yellowmottle and mosaic

Two viruses have already been identifiedinfecting black pepper in Brazil: mosaic causedby CMV-Pn and yellow mottle (PYMV).However, those viruses show distinctsymptoms which can be identified surely bypepper growers (Duarte et aI., 2001). Thosedifferences are observed in roots, stems andbranches, foliage, plant growth, transmissionand virus-vector insects (Table I).

Table 1.Differential symptoms between yellow mottle and mosaic on black pepper plants

Organs PYMV CMV-PnRoots Normal root svstern Poor root systemStems Necrotic points in vessel tissues Shorteninz of intemodesBranches Vascular discoloration, necrotic point Vascular discoloration, no necrotic pointsLeaves Yellow lemon and brilliant spots Diffuse chlorotic spots, malforrnation,

dispersed on foliar blade, chlorosis thickening, secondary veins glued,interveinal, waving margins, puckering puckeringin several infected leaves.

Inflorcscence Partiallv sterile flowers Reduced size, partially sterile flowersSpike Reduced number of fruit per spike Reduced spike size and number of fruit per

spikeVector-insect Pseudococcus elisae (mealy bugs) Aphis spiricolae (aphids)Transmission Stem cuttings, vector-insect, seeds, Stem cuttings, vector-insect, related and

related species, grafting cultivated species.

Hosts

Accessions 239 (Perumkodi ecotype) and1558 (KaluvaJly ecotype) selected to becropped under the shading were first infected.Those plants heavily infested with mealy bugsacted as inoculum source. Within four weeksthe disease had spread to laçará-I, Karimunda,Guajarina, Bragantina, Apra, Kottanadan-I andSingapore. All infected plants, more than fivehundreds, were eradicated by rouging.

Virus-vector insect

The constant association of mealy bugswith pepper plants exhibiting characteristicsymptoms of the disease suggest that PYMV istransmitted plant by plant by Pseudococcus

elisae Borshsenisius. It feeds in plant collar,branches, adventitious roots, inflorescence andspikes (Fig. 5). Female body shows ovularshape, measuring 1.2 mm to 2.0 mm, with 12lobules and 15 pairs of appendices. In the analregion two central, short and non waxedappendices can be seen. Eggs are long, orangecoloured and involved by a loose and cottonoustissues. In Southern Asia PYMV is transmittedby Planococccus citri (Lockhart et aI., 1997)

Control

Exclusion measures

In order to prevent the establishment ofPYMV in producer areas the following controlmeasures should be taken: a) Prohibition of

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free traffic of vegetative material frorn suspector contaminated area to free-disease areas; b)For vegetative prapagation get stem cuttingsfram free-disease plants, only; c) Inspectnurseries for new shoots showing diseasesymptoms, periodically; d) Establish forecastservices to keep pepper grawers informed onthe pragress of disease control,

Eradication measures

For many viruses meristem tissue culturehas been used to clean virus infectedgenotypes. There are evidences however,thatbadnavirus can be transmitted by meristemtissues. This will make difficult the genotypecleanness if the pathogen establishes in themain praducer areas. So, it is of primordialimportance to adopt the following measures ifinfected plants are detected in clonal gardens,nurseries or plantations: a) Interdict infectedclonal garden and nurseries keeping themunder narrow vigilance up to complete diseaseeradication. b) Cut all plants showing initialsymptoms of the disease. c) Control virus-vector insects with dimethoate, malathion,methyl parathion or diazinon insecticides. d)Control fire ants with pyretraid, carbamate ororganophosphorous insecticides. e) Eradicateinfected plants by rauging and keep plantsnearby eradicated ones under observation fornew shoots exhibiting virus disease symptoms.

REFERENCES

Albuquerque, F. c., Trindade, D. R.,Poltranieri, L. S., Duarte, M. 1. R., Brioso,P. S. T., Resende, J. A. M. & Kitajima, E.W. Evidências preliminares da ocorrênciado mosqueado amarelo da pimenteira-do-reino (Piper yellow mottle virus) no Brasil.In: CONGRESSO PAULISTA DEFITOPA TOLOGIA, 22, 1991. Jaboticabal,SP. Anais .. .Jaboticabal: Grupo Paulista deFitopatologia, 1999. p.ll04-105.

Bicudo, C. E. de M., Bicudo, R. M. T. Algasde águas continentais brasileiras. SãoPaulo: Fundação Brasileira paraDesenvolvimento do Ensino de Ciências.1970. 286p.

Duarte, M. L. R., Albuquerque, F. C. &Hamada, M. Murcha causada por Fusariumoxysporum, uma nova doença da pimenta-do-reino no Estado do Pará. FitopatologiaBrasileira, 24:78-181. 1999.

Duarte, N. L. R., Albuquerque, F. c.,Poltranieri, L. S. & Costa, A. P. D.Epidemias de podridão negra dos frutos dapimenta-do-reino causadas por Cephaleurosvirescens no Estado do Pará. FitopatologiaBrasileira, 25(Suplemento):349. 2000.

Duarte, M. L. R., Albuquerque, F. c.,Poltranieri, L. S., Trindade, D. R., Kitajima,E. W. & Brioso, P. S. T. Mosqueadoamarelo da pimenta-do-reino. Belém:Embrapa Amazônia Oriental, 2001, 30 p.(Embrapa Amazônia Oriental. Documentos,... ) (no prelo).

Holcomb, G. E. Hosts of the parasitic algaCephaleuros virescens in Louisiana andnew hosts records for the continental UnitedStates. Plant Disease, 70(11):1080-1083.1986

Holliday, P. Suspected virus in black pepper.Phytopathology News, 5: 1-49. 1959

INTERNATIONAL PEPPER COMMUNITY.28th Session. Chiang Mai, Thailand. 2000.

Joubert, J. J. & Rijkenberg, F. H. J. Parasiticgreen algae. Annual Review ofPhytopathology, 9:45-64. 1971

Lockhart, B. F. L., Kyratiya-Angul, K., Jones,P., Eng, L., De Silva, P., Olszewskki, N. E.,Deema, N. & Sanglang, J. Identification ofPiper yellow mottle virus, a mealybug-transmitted badnavirus infecting Piper spp.In Southem Asia. European Journal ofPlant Pathology, 103:303-311.1997.

Marlatt, R. B. & Alfieri, S. A. Jr. Hosts of aparasitic alga, Cephaleuros sp. PlantDisease, 64:1010-1011. 1980.

Wellman, F. L. Tropical American PlantDisease. Scarecraw Press, Inc., Metuchen,N. J. 989 p.

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Fig. 1: Black pepper cultivar Guajarinashowing generalised yellowish due to vascular

invasion caused by Fusarium oxysporum.

Fig. 2: Internodes of Guajarina exhibitingunilateral necrosis, characteristic symptoms of

yellow wilt (Fusarium oxysporum) in the main branch.

Fig. 3: Black brilliant spots with resinous appearance and irregularmargins dispersed on pepper leaves caused by the alga

Cephaleuros virescens.

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Fig. 4: Kottanadan-I leaves showing yellow and brílliant mottle and wavingmargins, typical symptoms of PYMV on black pepper.

Fig. 5: Mealy bugs (Pseudococcus elisae) feeding on black pepper branches.

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