Characterization and Evaluation of Indigenous Bacillus thuringiensis Isolate T352 against Fall Armyworm, Spodoptera frugiperda (J.E. Smith)

Abstract

Bacillus thuringiensis (Bt) Berliner is a ubiquitous soil bacterium with commercial bio pesticidal value and widely used for effective control of various important agricultural insect pests. Invasion of Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) into India caused potential yield loss in maize production, and also it threats the cultivation of other related crops. This study was aimed to characterize and evaluate the pathogenic activity of indigenous Bt isolate T352 against fall armyworm (FAW), S. frugiperda. The Bt isolate T352 was creamy white in colour and had irregular shaped flat colonies with undulated margin. Bipyramidal shape of parasporal inclusions was found in isolate T352. The isolate produced protein bands of ̴ 130 kDa and ̴ 65 kDa size in SDS PAGE analysis. PCR screening also confirmed the presence of cry1Ab, cry1Ac, cry2Aa, cry2Ab and vip3A genes. During probit analysis, isolate T352 exhibited the LC50 of 1.927 µg/ml as against 0.421µg/ml in positive standard strain HD- 1 based on mortality observed at 72 h after treatment in leaf disc bioassay with spore crystal mixtures.