Abstract: 【Aim】 To evaluate the toxicity and risks of four commonly used insecticide formulations 25% thiamethoxam water dispersible granule (WG), 4.5% β-cypermethrin microemulsion (ME), 1.8% avermectin emulsifiable concentrate (EC), and 12% benzoate·chlorfenapyr suspension concentrate (SC) to Vespa magnifica. 【Methods】 The acute oral toxicity of the above four insecticide formulations to both worker adults and larvae of V. magnifica, and the acute contact toxicity to its worker adults, were determined by oral-feeding and topical application, respectively. And the risk of the four insecticide formulations to the worker adults and larvae of V. magnifica were evaluated by combining with the hazard quotients calculated from the recommended field application rate. 【Results】 The 48-h oral median lethal dose (LD₅₀) values of the four insecticide formulations 25% thiamethoxam WG, 4.5% β-cypermethrin ME, 1.8% avermectin EC, and 12% benzoate·chlorfenapyr SC against the worker adults of V. magnifica were 2.43×1^0-2, 4.22, 3.61×10^-2 and 5.21×10^-2 μg a.i. per wasp, respectively, the 48-h contact LD₅₀ values against the worker adults of V. magnifica were 3.51×10^-2, 4.07, 7.86×10^-2 and 0.16 μg a.i. per wasp, respectively, and the 48-h oral LD₅₀ values against the worker larvae of V. magnifica were 1.92×10^-2, 2.76, 4.54×10^-2 and 0.24 μg a.i. per wasp, respectively. The results of risk assessment showed that 25% thiamethoxam WG, 1.8% avermectin EC and 12% benzoate chlorfenapyr SC had high toxicity and high risk, and 4.5% β-cypermethrin ME had medium toxicity and medium risk to the worker adults and larvae of V. magnifica. 【Conclusion】 The four insecticides have high toxicity and high risk or medium toxicity and medium risk to V. magnifica. The risks are unacceptable. It is recommended to carry out further risk assessment of the high-risk formulations and avoid the overlap of pesticide spraying time with the outgoing peak of V. magnifica.

Key words: Vespa magnifica, insecticides, oral-feeding, topical application, acute toxicity, risk assessment