Integrated Management of White Mold of Phaseolus vulgaris With Special Reference to Trichoderma Species

摘要

Two species of Trichoderma viz, T. viride Rifai and T. harzianum Rifai and Gliocladium virens Miller Gidden and Foster were evaluated under in viro and in field against Sclerotinia sclewtiorum, the causal agent of white mold of rajmash (Phaseolus vulgaris L.). In dual culture, T. viride grew 67 mm as compared to 24 mm of S. sclewtiorum after 72 h. Microscopic examination revealed that T.viride caused lysis and protoplasmic disintegration of mycelia of S. sclerotiorum while G.virens produced apperssoria like structure which gave rise to infection hyphae thereby penetrating the pathogen cell wall and causing inter-cellular parasitism. Radial growth of T.viride was more in monoculture than in dual culture. Carbendazim and benomyl (50 ug/ml) resulted incomplete inhibition of growth of T.viride and G.virens while Captan (250 jig/ml) was the least inhibitory to both bioagents. They exhibited good tolerance to Rovral and Roko. Soil applications of biocontrol agents were more effective in reducing disease(by 21-32%) than foliar applications. In an integrated method, a combination of delayed sowing (15 d), wider spacing, seed treatment with carbendazim @ 2 g/kg seed and two foliar sprays @ 0.05% resulted in a maximum disease control (78%) and yield (2035kg/ha).