Study on Insecticidal Activity of Bacillus thuringiensis Isolates against Lasioderma serricorne

For investigating the feasibility of stored tobacco pest control with Bt, 952 Bt strains were isolated with sodium acetate restraining from 225 samples among 521 samples collected from different tobacco warehouses of 7major cigarette factories.The distribution rate of Bt was 100%and the detectable rate of Bt was 43.19%.The virulence against 2-3 instar larvas was determined preliminarily with fermented solutions of 600 isolated strains.The result showed that there were 18 strains showing higher toxicity, the corrected mortality of the larva was above 73% in 9 days after applying.