SPECIFICITY AND INSECTICIDAL ACTIVITY OF CHILEAN STRAINS OF BACILLUS-THURINGIENSIS

Twenty-eight samples containing Bacillus thuringiensis were obtained f rom 137 soil samples collected from the Maule Region of Chile. Two iso lates were selected for evaluation of insecticidal activity against tw o agronomically important insects, according to the following criteria : colony and parasporal inclusion morphology, SDS-PAGE, Western blot, and flagellar serotypes. Results showed that strains indexed as 114 (v ar. kurstaki serotype H3a3b3c) and G11g (var. kenyae serotype H4a4C) s ynthesized entomocidal proteins of the Cry I group. The insecticidal a ctivity of strain 114 was similar to control strain var. kurstaki HD-1 toward Scrobipalpula absoluta larvae and presented 30% of activity of control strain against Helicoverpa zea larvae. Isolate G11g was found to be approximately 20% less active than the other screened strains. (C) 1995 Academic Press, Inc.