Weight as a Variable in the Response of the Western Spruce Budworm to Insecticides13

Abstract

The hypothesis that the response of Choristoneura occidentalis Freeman to mexacarbate, pyrethrins, and DDT is proportional to body weight was investigated by using multiple probit and logit regressions. For each chemical, different sampling procedures, weight ranges, and dose adjustment procedures were compared when testing for proportional response. The hypothesis of proportional response was generally rejected for all three chemicals. These results suggest that proportional adjustment may produce misleading inferences in topical application experiments.