常用杀虫剂对菜蛾绒茧蜂的影响及毒理机制研究

The Susceptibilities to the Commercial Insecticides and theToxicological Mechanism in Parasitoids Apanteles plutellae Kurd

田间采集试虫室内测定结果表明 ,敌敌畏、灭多威和杀虫双对菜蛾绒茧蜂 Ap anteles plutellae高毒 ,乙酰甲胺磷对绒茧蜂毒性较低 ,而氰戊菊酯、氯氰菊酯、氟虫腈、阿维菌素、定虫隆和 Bt则是低毒的。菜蛾绒茧蜂 ACh E的 Km 及 Vmax值分别是小菜蛾的 0 .2 2和 2 .0 8倍 ,ACh E对敌敌畏的敏感性 (Ki 值 )分别是小菜蛾的 10 .37倍。 10 0 mg/ L的胡椒基丁醚 (PB)或磷酸三苯酯 (TPP)均可使氰戊菊酯明显增效 ,其中 PB的增效作用显著高于 TPP。体内抑制实验结果表明 ,PB和 TPP对绒茧蜂 ACh E活力无显著影响 ,低浓度 (10 0 mg/ L)的 PB即可显著抑制绒茧蜂的 α- NA和 β- NACar E活力 ,且抑制率高于 TPP,TPP仅在高浓度 (10 0 0 mg/ L)时对绒茧蜂的两种 Car E活力有显著抑制作用。由此推断 ,与小菜蛾相比 ,菜蛾绒茧蜂对有机磷的高敏感性与其显著较高的 ACh E敏感性有关 ;此外 。

The dry vial film method was adopted in the bioassay of Apanteles plutellae , a larval parasitoid of Plutella xylostella by treating with the insecticides for 1 h and recording the mortality 8 h after treatment. Compared with the conventional control dosage to P. xylostella , dichlorvos,methomyl and bisultap were high toxic to A. plutellae , but acephate,fenvalerate, cypermethrin,fipronil,abamectin, chlorfluazuron and Bt were not. The apparent michaelis menten constant ( K m) and maximal velocity ( V max ) in A.plutellae were 0.22 and 2.08 times as high as those in its host P.xylostella , and bimolecular rate constant ( K i) to dichlorvos in A.plutellae were 10.37 times as high as those in P. xylostella , respectively. There were obviously synergistic effects on fenvalerate by combined with 100 mg/L piperonyl butoxide (PB) or triphenyl phosphate (TPP) in A.plutellae , and the synergisms of PB to the insecticides were higher. PB and TPP showed very weak inhibition on the activity of acetylcholinesterase(AChE), in vivo . Low concentration of PB (100 mg/L) showed strong inhibition on CarE activity, while only at high concentration(1 000 mg/L) could TPP exhibited significant inhibition on CarE activity. It were speculated that the high susceptibilities to organophosphates and carbamates in A.plutellae were related to its high sensitivity of AChE to the insecticides. In addition, the oxidative metabolism might be more effective in the tolerance to the insecticides than non oxidative metabolism in A.plutellae.