Activity of the β-Exotoxin of Bacillus thuringiensis var. thuringiensis against the Colorado Potato Beetle (Coleoptera: Chrysomelidae) and Bacterial Mutagenic Response as Determined by the Ames Test

Abstract

The potential bacterial mutagenicity of the beta-exotoxin of Bacillus thuringiensis var. thuringiensis was detennined by the Salmollella-microsomal assay (Ames test) and found to be nonmutagenic. The activity of three experimental preparations of B. thuringiensis var. thuringiensis were determined by feeding the preparations to house fly larvae and to neonateColorado potato beetle larvae, Leplinotarsa decemlineala (Say). Comparisons with controls were made as to food consumption and mortality rates, and the LDIOthrough LDQ, were calculated. In field tests of 0.05-ha plots of potatoes, an experimental preparation of B. lhuringiensis var. lhurillgiellsis provided excellent control of the Colorado potato beetle when applied weekly at the rate of 1,892 ml/O.4 ha.