BIOEFFICACY OF WETTABLE POWDER FORMULATION OF NATIVE BACILLUS THURINGIENSIS ISOLATE AGAINST MAJOR LEPIDOPTERAN PESTS IN THE LABORATORY

ABSTRACT Biofilm based antagonists were evaluated for growth promotion and soil borne disease The bioefficacy of the Bacillus thuringiensis (Berliner) Cry proteins in filed condition can be improved by developing formulation. In the presence study, we have developed and evaluated native Bacillus thuringiensis (Bt) isolate for the pathogenic activity against major lepidopteran pests viz., Helicoverpa armigera, Spodoptera litura and Plutella xylostella. The bioassay of the Bacillus thuringiensis crystal spore mixture against H. armigera registered 36.67 to 96.67 per cent mortality at 120 h after feeding. Reference strain HD1 showed highest mortality of 100 per cent. Lyophilized native B. thuringiensis (BGC-1) and B. thuringiensis (HD-1) were tested against H. armigera, recorded mortality ranging from 16.67 to 96.67 per cent. The LC50 value of B. thuringiensis (BGC-1) and B. thuringiensis (HD-1) were 6.08 and 9.18 ng/ml respectively. Bioefficacy of WP formulations of BGC-1 and HD-1 were recorded ranging from 32.50 to 95.00 and 35.00 to 97.50 percent mortality respectively at different concentration. The same WP formulation was also tested against S. litura and P. xylostella, recorded 87.50 and 95.00 per cent mortality for S. litura and P. xylostella, respectively. The study concludes that native isolate BGC-1 was found to be promising against major lepidopteran pests.