Naturally occurring Bacillus thuringiensis in oceanic islands of Japan, Daito-shoto and Ogasawara-shoto

抄録

A total of 307 soil samples, collected from two groups of Japanese oceanic islands (Daito-shoto and Ogasawara-shoto) were examined for the natural occurrence of Bacillus thuringiensis. B. thuringiensis was found in 15.3% of the soil samples, with 1.3% of the colonies belonging to the Bacillus cereus/B. thuringiensis group. Soils of the islands yielded at least 21 H serotypes. Insecticidal activities against Bombyx mori and/or Aedes aegypti were associated with 8.5% of the B. thuringiensis isolates. Among the insecticidal isolates, those belonging to the serotype H25 (serovar coreanensis) occurred predominantly.