The inheritance of diazinon resistance in an Australian strain of Musca domesticaL.

The genetics of diazinon resistance in an Australian strain of Musca domestica L. was investigated by means of two series of repeated back-crosses of the hybrid resistant form to the susceptible. Resistance was maintained through nine and eleven generations in the separate studies. The ratio of susceptible to resistant hybrid flies found in the progeny of each cross was approximately 1:1. In the second series, the frequency data were supported by dosage/response information on the relationship between dosage of insecticide and mortality. Together with the result of a previous study, the data furnish strong evidence that a fully dominant factor is responsible for the diazinon resistance in the Perth strain of house-flies resistant to organic phosphate insecticides.