Isolation and characterization of indigenous Bacillus thuringiensis Berliner from animal ordure effective against South American tomato pinworm, Tuta absoluta (Meyrick)

Abstract

Studies were carried out for identification of effective indigenous Bacillus thuringiensis (Bt) strain from animal ordure. Eight Bt isolate were isolated from five different indigenous animal ordure samples samples viz., rice moth faecal pellet, cow dung, poultry, goat, pig wastes and characterized along with reference Bacillus thuringiensis strain (HD1). The bacterial culture colonies were creamy white to milky white in colour, circular or irregular in shape with entire or partially serrated margins. Bt isolates were rod-shaped, gram positive with endospore and parasporal body produced at sporulation stage. Further the protein profile analysis revealed that all isolates showed major protein bands around 135, 110, 60-75, 48 and 20-30 kDa. These proteins may belong to Cryl and Cry2 protoxin. Bt isolates showed significant differences in their toxicity to the 2nd instar larvae of Tuta absoluta wherein mortality ranged from 70 to 100 per cent as compared to 1.67 per cent in control. Among the isolates, KGS2 isolate was considered as best and caused 65.0042.31, 90.0043.37 and 100.00+0.00 per cent mortality on 3", 5" and 7" day, respectively compared to other isolates.