Occurrence of Bacillus thuringiensis in canopies of a natural lucidophyllous forest in Japan.

A total of 39 Bacillus thuringiensis isolates were recovered from 38 leaves collected from 5- to 10-m-high canopies of 8 micro-/meso-phanerophyte species in a lucidophyllous forest of Japan. B. thuringiensis-positive leaves accounted for 1.4% of a total of 2805 leaves from 15 tree species. The frequency of the organism was 0.8% among the Bacillus cereus/B. thuringiensis group. Of 39 isolates obtained, 27 (69.2%) were allocated to 11 H serovars, and 12 isolates remained unidentified: 11 were motile but lacked reactivity to the 55 reference antisera, and 1 isolate was not flagellated. Two H serovars, kurstaki (H3abc) and tohokuensis (H17), occurred predominantly on canopy phylloplanes. Larvicidal activities against Bombyx mori and/or Aedes aegypti were associated with 49% of the canopy isolates. Strong hemolysis was induced by parasporal inclusion proteins of the two isolates of serovar israelensis (H14). Hemagglutinating (lectin) activity was associated with parasporal proteins of nine isolates. There was little correlation between insecticidal activity and lectin activity.