Analysis of Toxicity and Safety of Common Pesticides in Tobacco on Encarsia formosa

This study evaluated the toxic effects of 21 commonly used pesticides on adults and pupal parasitoids of Encarsia formosa using residual film and dipping methods, and conducted a risk assessment based on safety factors (SF) and eclosion inhibition rates, aiming to provide a scientific basis for integrating biological and chemical control strategies in the Huanghuai tobacco-growing regions. The results showed that based on the toxicity to E. formosa adults, two pesticides were classified as high risk both insecticides, safety factor (SF) <0.5; twelve as medium risk (SF 0.5–5.0, including insecticides, fungicides, and bud inhibitors);and seven as low risk (SF>5.0, primarily plant immunity inducers and bio-source fungicides). Eight pesticides showed eclosion inhibition rates of 50%-80% (including seven insecticides and the bud inhibitor flumetralin), categorized as medium risk; thirteen pesticides had inhibition rates of 20%–50% (including three insecticides, all fungicides, plant immunity inducers and herbicide), classified as low risk. In conclusion, most insecticides pose medium to high risks to both adults and pupae of E. formosa. Therefore, their application should be avoided during the wasp release period and peak eclosion phase. Certain fungicides and bud inhibitors also affect E. formosa. Priority should be given to low-risk alternatives, with optimized application methods to achieve synergistic pest control.