ABSTRACT
Bacillus thuringiensis (Berliner) (Eubacteriales: Bacillaceae), first isolated from diseased silkworm larvae in 1901, was recognized for its utility in pest control under field conditions in late 1920s. The growing importance of B. thuringiensis (Bt) as a bioinsecticide over the last few decades has led to renewed efforts in isolation, identification and characterization of strains, and more than 60,000 isolates have been collected in various institutions all over the world. Currently, more than 80 serovars of Bt have been found to be pathogenic to insects, and more than 200 products registered for insecticidal use. Bacterial insecticides are highly effective, specific, safe to parasitoids and higher animals and are environmentally benign (Entwistle et al. 1993). Hence, these have become a dominant group (about 90%) in the bioinsecticides market in the world.
