Relative Toxicity of Two Synthetic Pyrethroids to a Predator Amblyseius fallacis and Its Prey Tetranychus urticae123

Laboratory tests showed that the synthetic pyrethroids, permethrin and fenvalerate, were highly toxic to the phytoseiid mite Amblyseius fallacis (Garman) and relatively innocuous to the twospotted spider mite, Tetranychus urticae Koch. These results indicate that the use of permethrin and fenvalerate is detrimental to orchard integrated mite control programs where A. fallacis is the key predator of spider mites.