Studies on the insect-resistance to insecticides : V. Control of the chlorinated hydrocarbon resistant house fly by adding S-421 as synergist in insecticides

Abstract

Effect of octachlorodiprophylether (S 421), a synergist for pyrethrins and allethrin, was studied in an attempt to utilize as a synergist against resistant and susceptible colonies of the house fly, Musca domestica vicina and M. d. domestica. The result shows that the S 421 will be able to consider as a suitable synergist for pyrethrins and allethrin. In case of allethrin S 421 showed a definite superiority over piperonyl butoxide as has been known using European house flies. The p, p′-DDT or technical DDT plus octachlorodipropylether (S 421) showed a remarkable synergistic activity against the Japanese vicina, indicated the original high tolerance to DDT, as compared with the activity of p, p′-DDT or technical DDT alone. The optimum ratio of the content of S 421 to the content of DDT was 0.2 to 1. Similarly, the efficacy of γ-BHC or dieldrin added with S 421 at a ratio of 1 : 1-10 proved to be far higher than that of γ-BHC or dieldrin alone against the resistant populations, whereas it imparted a slight increase in efficacy against the susceptible populations.