Screening and Identification of Potential Bacillus Spp. for the Management of Bacterial Wilt of Brinjal

Abstract

Among 100 isolates of Bacillus spp. screened in vitro against Ralstonia solanacearum that causes bacterial wilt of brinjal, ten were found inhibitory to R. solanacearum. Bacillus megaterium isolate NBAII 63 was highly inhibitory with 29.20 mm of inhibition zone against R. solanacearum as compared to the other nine strains of Bacillus. Six of them were identified by 16S rDNA analysis. The bioefficacy of talc formulation of B. megaterium was evaluated under greenhouse for plant growth promotion and suppression of bacterial wilt in brinjal. The bacterial wilt was effectively managed by B. megaterium through different methods of applications. A combination of four methods (seed treatment + soil application + seedling root dip + foliar spray) was the most effective. Maximum root length (23.42 cm), shoot length (65.21 cm), fresh weight (40.39 g), dry weight (10.33 g) and highest wilt reduction (50.54%) was recorded in the combination method. Among single application methods, seed treatment was effective exhibiting 41% reduction of bacterial wilt followed by soil application which gave 36% wilt reduction. The bacterial wilt reduction in chemical control (streptomycin sulphate) was 71%. Good growth of the brinjal plants was recorded due to application of B. megaterium. Highest rhizosphere population of 67.0 í— 10⁶ cfu/g was recorded in brinjal at 40 days after transplanting when the antagonist was applied by combining the different application methods.