小菜蛾幼虫对拟除虫菊酯类杀虫剂的抗药性与多功能氧化酶的关系

RESISTANCE OF DIAMONDBACK MOTH TO SYNTHETIC PYRETHROIDS AND ITS RELATIONSHIP WITH MICROSOMAL MIXED-FOUNCTION OXIDASE

作者就上海梅陇、广州天河和江西莲塘的小菜蛾对拟除虫菊酯的抗药性及其与微粒体多功能氧化酶(MFO)的关系进行了研究。结果表明,上海种群(R)对溴氰菊酯、氰戊菊酯和氯菊酯的 LD_(50)分别是江西种群(S)的>10414倍、2102倍和245倍。广州种群分别为>10414倍、>3569倍和1533倍。活体增效试验表明,酯酶抑制剂 TBPT 在低剂量(0.208μg/虫)时,对溴氰菊酯和氯菊酯都无增效作用,在高剂量(2.08μg/虫)时分别增效41.7倍和110倍。用 MFO的抑制剂 PB 作同样处理时,低剂量的 PB 对溴氰菊酯和氯菊酯的增效作用分别为5倍和12.9倍;高剂量的 PB 对溴氰菊酯增效562倍以上。^(14)C-氰戊菊酯代谢的离体研究结果表明,R 小菜蛾代谢^(14)C-氰戊菊酯的速度是 S 小菜蛾的2.1倍,TBPT 抑制^(14)C-杀灭菊酯的代谢约20%,而PB 抑制50%以上。由此可以得出结论,MFO 是小菜蛾对拟除虫菊酯的主要机理之一。

Resistance of several field strains of diamondback moth(DBM),Plutella xylostella(L.),in southern China to synthetic pyrethroid(SP)insecticides,and the relationship between pyrethroid-resistance andmixed-founction oxidase(MFO)were investigated.The results tested bytopical applications showed that Shanghai strain developed resistanceto deltamethrin(more than 10414-fold),to permethrin(245-fold),andto fenvalerate(2102-fold),while Guangzhou strain possessed more than10414-fold,1533-fold and more than 3569-fold resistance to the abovepyrethroids respectively,as compared with Nanchang strain.TBPT,aninhibitor of esterases,didn't exhibit any synergism to either deltameth-rin or permethrin at a dosage of 0.208μg/larva,but at 2.08μg/larva,itcould synergize the toxicity of these two SP insecticides,while PB,aMFO inhibitor,did exhibit significantly synergism to SP at both 0.208μg/larva and 2.08μg/larva.The in vitro study of [^(14)C]-fenvalerate me-tabolism indicated:(1)the degradation rate of R strain was 2.1 timesthat of S strain;(2)1×10^(-5) mol/L TBPT inhibited 21% of [^(14)C]-fen-valerate metabolism,while 1×10^(-5) mol/L PB inhibited more then 50%.The in vivo and in vitro data suggested that MFO was one of the majorresistance mechanisms in SP-resistant DBM.