STUDIES ON SOIL BORNE DISEASES OF BRINJAL (SOLANUM MELONGENA L.)
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Date
2010
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Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu
Abstract
The eggplant or brinjal (Solarium melongena L.) is an important commercial vegetable crop of Jammu region accounting for 950 ha area with total production of 13,775 MT. Brinjal crop suffers from many biotic stresses, out of which soil borne diseases are of great economic importance. Studies were carried out from 2007 to 2009 with the objectives to know the status of these diseases, causal agents involved, synergistic effect of different pathogens on wilt incidence and growth parameters and to arrive at the effective disease management strategies. The soil borne diseases were found to prevail in all the areas surveyed. The pooled data of the years 2008 and 2009, indicated that per cent seedling mortality and wilt incidence ranged from 13.25 to 29.50 and 16.05 to 37.55 per cent, respectively. Pathogenicity tests indicated that Fusarium oxysporum f. sp. melongenae (Fo), Pythium aphanidermatum (Pa), Rhizoctonia solani (Rs), Meloidogyne incognita (Mi) and Ralastonia solanacearum (Ra) were the causal organisms associated with the soil borne diseases of brinjal crop. The interaction study between isolated soil borne pathogens showed that wilt incidence was invariably greater when Meloidogyne incognita was present in combinations with wilt pathogenic bacteria and fungi. The studies revealed that the pathogens individually and in various combinations caused significant increase in wilt incidence and reduction in plant growth index parameters. Maximum wilt incidence of 100 per cent was observed, when plants were inoculated with Mi+Fo+Rs+Ra at 30 days after transplanting (DAT). Similarly, maximum reduction in plant height, shoot weight, root weight and yield was observed in plants inoculated with Mi+Fo+Rs+Ra treatment. The data also depicted that maximum nematode count was found in pots inoculated with Mi alone. It was observed that most of the fungal and bacterial antagonists tested were found effective against soil borne diseases under in vitro and in vivo conditions. Among fungal antagonists isolate Tv<sub>4</sub> (Trichoderma viride) and among bacterial antagonists isolate Pf<sub>2</sub> (Pseudomonas fluorescens) were found most efficacious against the soil borne pathogens. Pot studies revealed that seed and soil application of antagonists resulted in significantly higher seed germination and seedling emergence compared to seed and soil application alone. Pot studies further revealed that seed + seedling + soil application of the antagonists resulted in lesser wilt incidence compared to only seed + seedling or soil application of these antagonists. Among 72 germplasm screened Arka Nidhi recorded minimum mortality under nursery conditions, whereas, in pot conditions Arka Nidhi, Black Beauty, Arka Neelkanth, Arka Sheel, Arka Keshav recorded minimum seedling mortality. Swaran Shamli, Arka Nidhi, Banaras Giant, Arka Neelkanth, Pusa Purple Round, Pusa Purple Cluster, Arka Sheel, Hisar Shyamal and Arka Keshav were resistant to wilt complex disease under field conditions, whereas, in pot conditions Swaran Shamli, Arka Nidhi, Banaras Giant, Arka Neelkanth, Pusa Purple Cluster, Arka Sheel, Hisar Shyamal and Arka Keshav were resistant to wilt complex disease. In vitro evaluation of fungicides against fungal soil borne pathogens revealed that carbendazim was most effective against Fo and Rs at all the concentrations tested, whereas, in case of Pa metalaxyl + mancozeb was most efficacious at all the concentrations tested with cent per cent inhibition. In case of Ra, combination of streptomycin sulphate + tetracycline was efficacious antibiotic. Under in vivo conditions it was found that, soil solarization + seed treatment with metalaxyl + mancozeb was most effective integrated disease management (IDM) approach in reducing the damping-off disease. On the other hand, root dip treatment with carbendazim + drench with carbendazim at 15 day intervals was effective IDM strategy in reducing the wilt incidence.
Keywords: soil borne diseases of brinjal, incidence, frequency of pathogens, interaction between pathogens, screening, biological, chemical and integrated management.
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