Toxicity to House Flies of the Pyrethrins and Cinerins, and Derivatives, in Relation to Chemical Structure

Abstract

The relative toxicity to house flies (Musca domestica) of certain constituents of pyrethrum flowers and some of their hydrogenated derivatives was detd. by the turntable method. Both pyrethrin II and cinerin II were about 25% as toxic as the corresponding type I compounds. Both cinerins, as well as isodihydrocinerin I, were about 67% as toxic as the corresponding pyrethrin compounds. Both type I compounds were about twice as toxic as their isodihydro derivatives. Pyrethrin I was about twice as toxic as the mixture of "pyrethrins" contained in the ordinary pyrethrum kerosene extract. The toxicity of isodihydropyrethrin II and isodihydrocinerin II was negligible at the conc. levels of the pyrethrum standard tests. Tetrahydropyrethrin I had low toxicity as compared with the pyrethrum standard[long dash]<6.25% as much.