LABORATORY BIOASSAYS OF MIXTURES OF BACILLUS THURINGIENSIS AND CHITINASE

Publisher Website
Google Scholar
Abstract
The addition of chitinase at the rate of 1000–4000 nephelometric units/U.S. gallon to Bacillus thuringiensis insecticide for use against spruce budworm has been advocated.Bioassays of V instar spruce budworm larvae against seven levels of Thuricide® at four levels of chitinase corresponding to 0, 22, 220, and 2200 nephelometric units/U.S. gallon were conducted by placing larvae on balsam fir foliage (Abies balsamea) dipped in appropriate dilutions of Thuricide® with chitinase. Mortality was assessed 6 days later. An additional replicated assay at a relatively massive dose of chitinase, 33,000 nephelometric units/U.S. gallon, was compared simultaneously with a 0 chitinase control. The data were homogeneous and linear by statistical standards. No effect of chitinase on LC50 or slope of the regression line was observed.