关键词: 桃蚜, 噻虫胺, 毒力, 酶抑制剂, 亚致死剂量, 解毒酶, 酶活力

Abstract: In order to clarify the toxicity of clothianidin to Myzus persicae (Sulzer) and the metabolic detoxification mechanisms in the aphid, the toxicity of clothianidin to M. persicae was detected using topical application, leaf dipping and petiole wrapping methods, the synergism of piperoayl butoxide (PBO), triphenyl phosphate (TPP) and diethylmaleate (DEM) to clothianidin was determined, and the influence of sublethal doses of clothianidin on detoxifying enzymes was determined with biochemical method at the doses of LC₆, LC₁₅ and LC₃₀. The results showed that the LC₅₀ values through guttate, impregnation and systemic toxicity were 1.891, 2.341 and 1.303 mg/L, respectively. The synergism ratios of PBO and TPP to clothianidin were 2.41 and 1.52, respectively, whereas DEM had no significant synergism to clothianidin. Under the treatment of sublethal doses of clothianidin, the specific activity of AChE was inhibited significantly at 24 h after treatment, and its inhibition rate reached 41.2% at the dose of LC₃₀; the specific activity of CarE, however, increased obviously, and the synergistic ratios at the doses of LC₁₅ and LC₃₀ at 24 h after treatment were 1.29 and 1.36, respectively; and the GST activity was also inhibited significantly with the inhibition rates of 7.9%, 11.9% and 22.7% at the doses of LC₆, LC₁₅ and LC₃₀, respectively. These results suggest that clothianidin has high toxicity to M. persicae, and GST and MFO may be the major detoxifying enzymes in metabolizing clothianidin in the aphid.

Key words: Myzus persicae, clothianidin, toxicity, synergist, sublethal dose, detoxifying enzyme, enzyme activity