An attempt was made to select new Bacillus thuringiensis strains in order to control dipteran pests that cause economic damage to agricultural product cultivation sites. To select B. thuringiensis strains, the insecticidal activities of B. thuringiensis strains against the larvae of Lycoriella ingenua, mushroom flies and Bradysia agrestis, fungus gnats which are major agricultural pests, and Aedes albopictus, which is a hygiene pest were investigated. From among the 5 B. thuringiensis strains of which the biological activity was investigated, one strain, B. thuringiensis subsp. kyushuensis CAB571, which exhibited at least 90% insecticidal activity against L. ingenua and B. agrestis, was selected. The LC_95 values of the B. thuringiensis strain CAB571 against B. agrestis and L. ingenua were 8.7×10^7 (cfu/ml) and 3.5×10^6 (cfu/ml), respectively, indicating high insecticidal activities. The selected new B. thuringiensis strain was shown to have 5 major δ–endotoxin protein bands of about 150, 70, 65, 48 and 27 kDa on SDS–PAGE and 2 major endotoxin protein bands of about 65 kDa and 25 kDa in the reaction to trypsin treatment. This strain showed 8 plasmid DNA bands, and 4 genes, which are cry40A, cyt1C, cyt1D and cyt2Aa in PCR for crystal proteins.
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