Increased susceptibility of Manduca sexta to commercial formulations of the microbial insecticide, Bacillus thuringiensis, as evidenced by lower LD50 and LT50 values, was observed when M. sexta were reared on an artificial diet supplemented with a sublethal concentration (2.5 mm) of l-canavanine. At several dosages of B. thuringiensis, which were administered either by diet contamination or by per os forced feeding, a greater than 70% reduction (P < 0.05) occurred in the LT50 response with canavanine-treated larvae. The LD50 values also were lowered by canavanine treatment. This constitutes the first report of a plant allelochemical enhancing the effect of B. thuringiensis in vivo. It is suggested that canavanine enhances the effect of B. thuringiensis on gut permeability and active transport.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics