Pacific Southwest

Title: Lethal effects of five molt inhibitors fed to the western spruce budworm (Choristoneura occidentalis Freeman) (Lepidoptera: Tortricidae) and the Douglas-fir tussock moth (Orgyia pseudotsugata [McDonnough]) (Lepidoptera: Lymantriidae)

Author: Rappaport, N.G.; Robertson, J.L.

Date: 1981

Source: Pacific Southwest Forest and Range Experiment Station, Forest SErvice, U.S. Department of Agriculture, Berkeley, California U.S.A.

Description: Five insect molt inhibitors (MI's) were mixed with artificial diet and fed to 3rd and 6th stage western spruce budworm (Choristoneura occidentalis) larvae and 2nd stage Douglas-fir tussock moth (Orgyia pseudotsugata) larvae. In general, tussock moth larvae were more susceptible that western spruce budworm larvae to these MI's SIR 6874 was by far the most toxic to 3rd and 6th stage western spruce budworm, and diflubenzuron the least toxic. TH 75331 and EL-494 both showed sustantial activity against this insect, while SIR 8514 was relatively less active but was still at least 3 times as toxic as diflubenzuron. Except for EL-494, there were no large differences in toxicity of these compounds to 2nd stage tussock moth larvae; EL-494 was 30-90 times less toxic than the others at the LC₅₀. The other four MI's caused at least 50% mortality of 2nd stage tussock moth which were fed a diet containing less than 0.1 ppm of the MI's.

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Citation

Rappaport, N.G.; Robertson, J.L.  1981.  Lethal effects of five molt inhibitors fed to the western spruce budworm (Choristoneura occidentalis Freeman) (Lepidoptera: Tortricidae) and the Douglas-fir tussock moth (Orgyia pseudotsugata [McDonnough]) (Lepidoptera: Lymantriidae).   Pacific Southwest Forest and Range Experiment Station, Forest SErvice, U.S. Department of Agriculture, Berkeley, California U.S.A..