Distribution, Frequency, and Diversity of Bacillus thuringiensis in an Animal Feed Mill.

摘要: Bacillus thuringiensis was isolated from 36 of 50 residue samples obtained an animal feed mill (a stored-product environment). Of 710 selected colonies having cereus-B. morphology the samples, 477 were classified as B. because production parasporal delta-endotoxin crystals. There a diverse population thuringiensis, revealed by differentiation isolates into subgroups using (i) their spectra toxicity to lepidopterans Heliothis virescens, Pieris brassicae, and Spodoptera littoralis dipteran Aedes aegypti (ii) crystal morphology. A total 55% not toxic any these insects at concentrations used in bioassays; 40% all one or more Lepidoptera; 20, 1, 1% only P. H. S. littoralis, respectively. The most frequent brassicae (36% isolates); 18% A. (5% exclusively), 10% 4% littoralis. Toxicity often linked with virescens than frequency significantly greater that produced bipyramidal crystals irregular pointed, spherical, rectangular, spherical