Isolation of native Bacillus thuringiensis Berliner isolates from the agricultural soils of Iran

Isolation and collection of native B. thuringiensis isolates is the base of research on B. thuringiensis. During a -year study (999-00) 4 soil samples were collected from 8 provinces of Iran. Bacteria were isolated according modified method of Anwar Hossain et al. Most isolates were isolated from cotton, oil seed, sugar beat and rice field soil. Gilan and Ardabil provinces had been most isolates respectively. A total of 8 crystal- forming isolates were successfully obtained from 8,445 bacterial spore-forming colonies examined. Toxicity tests on Helicoverpa armigera (Lep: Noctoeidea) and Leptinotarsa decemlineata (Col.: Cherisomeliidea) revealed that over %58 of all isolates were toxic.