| Summary: | We evaluated the efficacy and residual toxicity of nine commercial insecticides on <i>Plutella xylostella</i> and their selectivity to the predator ant <i>Solenopsis saevissima</i> under laboratory and field conditions. First, to test the insecticides’ effectiveness and selectivity, we conducted concentration-response bioassays on both species and the mortalities were recorded 48 h after exposure. Next, rapeseed plants were sprayed following label rate recommendations in the field. Finally, insecticide-treated leaves were removed from the field up to 20 days after application and both organisms were exposed to them as in the first experiment. Our concentration-response bioassay indicated that seven insecticides caused mortality ≥80% of <i>P. xylostella</i>: bifenthrin, chlorfenapyr, chlorantraniliprole, cyantraniliprole, indoxacarb, spinetoram, and spinosad. However, only chlorantraniliprole and cyantraniliprole caused mortality ≤30% of <i>S. saevissima</i>. The residual bioassay indicated that four insecticides had a long-lasting effect, causing mortality of 100% to <i>P. xylostella</i> 20 days after application: chlorantraniliprole, cyantraniliprole, spinetoram, and spinosad. For <i>S. saevissima</i>, bifenthrin caused mortality of 100% during the evaluated period. Additionally, mortality rates below 30% occurred four days after the application of spinetoram and spinosad. Thus, chlorantraniliprole and cyantraniliprole are safe options for <i>P. xylostella</i> management since their efficacy favor <i>S. saevissima</i>.
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