Indoor Toxicity of Five Insecticides against Frankliniella occidentalis and Safety Evaluation for Neoseiulus barkeri

Purpose To screen insecticides that are effective against Frankliniella occidentalis and safe for Neoseiulus barkeri, providing a reference for the combined use of insecticides and predatory mites in controlling F. occidentalis.

Methods The bean pods treated with 60 g/L spinetoram suspension, matrine, 25% thiamethoxam water dispersible granules, 5% abamectin, and 70% imidacloprid, respectively, were used to feed F. occidentalis. After 48 hours, the control effect on F. occidentalis and the safety to N. barkeri were evaluated.

Results The insect decline rates of the above five insecticides to F. occidentalis were in turn of 97.78%, 95.00%, 92.22%, 88.89%, and 59.56%; the control effects were in turn of 97.52%, 94.43%, 91.34%, 87.43%, and 55.42%. Spinetoram, matrine, and thiamethoxam showed good control effects against F. occidentalis. Compared to the water control, the insect decline rates of matrine, thiamethoxam, spinetoram, imidacloprid, and abamectin were 11.37% , 9.71% , 9.15% , 8.04% and 4.70%, respectively. Among them, abamectin had the least impact on N. barkeri populations and was the safest.

Conclusion When used alone, spinetoram, matrine, and thiamethoxam can be recommended as effective insecticides for controlling F. occidentalis. When used in combination with predatory mites, abamectin can be used with N. barkeri to maximize the insecticidal effect and predatory mite efficacy. Spinetoram and thiamethoxam should be applied only after N. barkeri has been well established.