Toxicity of the Piperonyl Ester of Chrysanthemumic Acid and Some of Its Derivatives in Comparison with Allethrin and Pyrethrins as House Fly Sprays1

Eighteen related synthetic compounds, most of them substituted piperonyl esters of dl-cis-trans-chrysanthemumic acid, were tested as space sprays on the Campbell turntable against house flies, Musca domestica L. The most toxic were the 6-bromo and 6-chloropiperonyl esters, the latter now known as barthrin. They were, respectively, about 21 and 31% as toxic as allethrin, and 51 and 88% as toxic as pyrethrins at the 50% mortality level. Above this level the ratios were higher, reaching at the 95% mortality level to about 25 and 50%, respectively, as toxic as allethrin, and 90 and 200% as toxic as pyrethrins. The knockdown value of the esters, although excellent at highly toxic concentrations, was much inferior to that of allethrin or pyrethrins at comparable concentrations.