Deka, H. K.

Idicula, Sabu P.

Mondal, G. C.

English

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Management of purple root disease of Hevea255In India, purple root disease of Heveabrasiliensis seedlings in nursery caused byHelicobasidium compactum Boedijn was firstreported by Rajalakshmi and Joseph (1994) fromKerala State and in North East India by Mondal andDeka (2004).  The disease caused a heavy loss ofplants (above 45%) during 1998 in Meghalaya. InChina, violet (purple) root disease was reported tobe one of the major root diseases that destroys rubberplants of all age groups (Zhang and Chee, 1989aand 1989b; Zhang et al., 1990). Severe incidence ofpurple root disease on rubber caused  heavy loss inplant stand in Java and Indonesia (De Fluiter, 1939).H. compactum is reported to infect wide range ofhost plants like Eupatorium odoratum, Puerariaphaseoloides, Centrosema pubescens, Tectonagrandis (Rajalakshmi and Joseph, 1994; Mondal andDeka, 2004). Studies on the management of purpleroot disease of H. brasiliensis in India are scanty(Idicula et al., 2002). Thus, the study onidentification of effective and economic controlmeasures for the management of this diseaseassumes importance.A field trial was conducted on eight-month-old H. brasiliensis seedlings in nursery during2003-06 at District Development Centre, RubberBoard, Jenggitchakgre, Tura under West Garo HillsDistrict of Meghalaya. The nursery for thisexperiment was raised in a susceptible pocketwhere the mortality of seedlings due to purple rootdisease was above 45 per cent. During the first year,twelve treatments were imposed on eight-month-old seedling plants in a RBD with three replicationsper treatment (40 plants per replication) in thenursery (Table 1). The fungicides were sprayed onManagement of purple root disease ofHevea brasiliensis seedlings in nursery(Manuscript Received: 16-03-13, Revised: 10-06-13, Accepted: 01-07-13)Keywords: Bioflora, Hevea brasiliensis, North East India, purple root disease, seedling nursery, systemic fungicidesthe collar zone of seedlings for three rounds at aninterval of one month (1.5 litre solution bed-1 round-1).Disease incidence was estimated from one-year-old seedling plants in the experimental plots afterthe completion of treatments. To estimate diseaseincidence, the total number of seedling plants andtotal number of diseased seedlings per experimentalplot (3.0 x 1.2 m with 40 seedlings) were recorded,irrespective of the grade of the disease andexpressed as percentage. The reduction (%) inpurple root disease over control was alsocalculated. The experiment was repeated in anothersusceptible pocket of the nursery for one more yearafter leaving the nursery beds fallow for two years,for confirmation of the results.The incidence of purple root disease on theseedlings and reduction of disease over control indifferent experimental plots in nursery are presentedin Table 1. In untreated control plots (T1), theincidence of purple root disease on the seedlingswas very high (12%) after two years of study.Shrivelled appearance with sparse crown andprofuse growth of adventitious roots from the collarzone of Hevea seedlings were found in the advancedstages of infection (Fig. 1). The presence of 10 to15 cm long, resupinate, 6 to 10 mm thick purplecoloured distinct fruiting body girdling the collarzone of the infected seedlings was also observed astypical symptom of the disease (Fig. 2). Theinfection led to yellowing of leaves and causedmortality of the affected plants. Significant reductionof purple root disease was observed in all theexperimental plots except T8 and T9 compared tothe control. Reduction in disease by 35 and 68.4 percent were observed in T8 and T9 indicating that ifShort  Scientific  Report Journal of Plantation Crops, 2013, 41(2): 255-257Mondal et al.256respectively (Idicula et al., 2002). The efficacy oftridemorph, propiconazole and hexaconazole againstthe management of root disease of rubber was alsoreported (Lam and Chiu, 1993; Idicula et al., 2002).Cleaning of land by removing most of the rootfragments of the previous stands resulted insignificant reduction in potential sources of rootdisease (Zhang and Chee, 1989b; Zhang et al.,1990).Table 1. Effect and cost of different treatments used for management of purple root disease of Hevea seedlings in nurseryTreatments Incidence of purple root disease Percentage reduction Cost (` per bed of 40(Mean of two years) of disease over control seedlings per round)Mean of affected plants per Disease incidencereplication (nos.) (%)T1 (Untreated control) 4.8 12.0 - -T2 (Propiconazole 0.1%) 0.15 0.4 96.7 5.10T3 (Propiconazole 0.2%) 0 0 100 10.20T4 (Propiconazole 0.1% alternate withtridemorph 0.15%) 0 0 100 -T5 (Tridemorph 0.15%) 0 0 100 2.31T6 (Tridemorph 0.3%) 0 0 100 4.62T7 (Tridemorph 0.15% alternate withcarbendazim 0.15%) 0 0 100 -T8 (Carbendazim 0.15%) 3.1 7.8 35.0 3.46T9 (Carbendazim 0.3%) 1.5 3.8 68.4 6.93T10 (Carbendazim 0.15% alternate withpropiconazole 0.1%) 0 0 100 -T11 (Bioflora natural: 20g/bed) 0 0 100 4.80T12 (Fallow bed for two years) 0 0 100 -Fig. 1. Affected plant showing profuse growth of adventitious rootsfrom the collar zone of Hevea seedling with damaged tap rootthe dosage of the fungicides tested for control ofthe disease were increased, better control would havebeen possible. From this study, it is observed thattridemorph and propiconazole are effectivefungicides for the management of purple root diseaseof rubber. Similar result was obtained from SouthIndia where the effective concentration oftreidemorph and propiconazole against purple rootdisease were 0.25 per cent and 0.1 per cent,Fig. 2. Enlarged view of fruiting body (indicated by arrow) of thepathogen girdling the collar zone of the infected seedlingManagement of purple root disease of Hevea257Reduction in inoculum level while leavingbeds fallow for two years (T12) which made thebed devoid of living host was also reported earlierfrom South India (Idicula et al., 2002). However,soil from disease affected plantation continues tospread the disease for a long time (Huang, 1990) ifmixed with unaffected soil.The high cost of fungicides used in rootdisease management restricts planters fromspraying/drenching infected plants. It is observedthat among the treatments tried, tridemorph (0.15%)was the cheapest systemic fungicide (` 2.31 bed-1round-1) followed by bioflora natural (` 4.80 bed-1round-1) for the management of purple root disease(Table 1). It was also observed that fallow bed (T12)was economically better suited than the othertreatment for management of purple root disease ofH. brasiliensis seedlings in nursery.AcknowledgementsThe authors are grateful to Dr. N. M. Mathew,the former Director of Research and Dr. JamesJacob, the present Director of Research, RubberResearch Institute of India (RRII), Kottayam forproviding necessary facilities, guidance, constantencouragement and valuable suggestions. Thanksare also due to Dr. Dhurjati Choudhuri, ProjectCoordinator (NE), and Dr. Gitali Das, DeputyDirector, Regional Research Station, Guwahati fortheir support and editing the manuscript. The co-operation extended by the Development Officer,Rubber Board, District Development Centre,Jenggitchakgre, Tura, Meghalaya in conducting theexperimental trials is gratefully acknowledged.ReferencesDe Fluiter, H. J. 1939. Helicobasidium compactum Boedijn asa parasitic root fungus of Hevea brasiliensis.Bergcultures 13: 392-398.Huang, Y. 1990. Characteristics of occurrence and developmentof root diseases of rubber and integrated measures fortheir control in Yunnan. Proceedings of IRRDBSymposium, 1990, Kunming, China, pp. 9-18.Idicula, S.P., Prem, E.E., Manju, M.J., Mushriff, S.K. and Jacob,C.K. 2002. Purple root disease and its control in rubberplantations. Proceedings of Placrosym XV (2002)Mysore: 609-612.Lam, C.H. and Chiu, S.B. 1993. Hexaconazole (Anvil 5SC), acost-effective fungicide for controlling white rootdisease in immature rubber. The Planter 69: 465-474.Mondal, G.C. and Deka, H.K. 2004. Purple root disease ofHevea brasiliensis in nursery. A report from Assam andMeghalaya. Journal of Plantation Crops 32(Suppl.):391-394.Rajalakshmy, V.K. and Joseph, A. 1994. Purple root disease ofrubber: A new report for India. Indian Journal ofNatural Rubber Research 7(2): 75-78.Zhang, K.M. and Chee, K.H. 1989a. Hevea diseases ofeconomic importance in China. The Planter 65: 3-8.Zhang, K.M. and Chee, K.H. 1989b. Root diseases of rubber inChina and their control. The Planter 65: 443-451.Zhang, K., Zhang, Y., Zhou, S. and Zhong, H. 1990. Violet rootdisease in China’s rubber plantations. Proceedings ofIRRDB Symposium 1990, Kunming, China, pp. 37-46.Rubber Research Institute of India, Regional Reseasrch Station,Housefed Complex, Dispur, Guwahati-781 006, Assam, India1Rubber Research Institute of India, Kottayam - 686 009,Kerala, IndiaG.C. Mondal *H.K. DekaSabu P. Idicula1*Corresponding Author: gopalchandra@rubberboard.org.in

Management of purple root disease of Hevea brasiliensis seedlings in nursery

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Management of purple root disease of Hevea brasiliensis seedlings in nursery

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