甜菜夜蛾对甲氧虫酰肼抗药性选育及其抗性生化机理初探

在室内用甲氧虫酰肼对甜菜夜蛾Spodoptera exigua(Hübner)幼虫进行抗药性选育,经过13代汰选,甜菜夜蛾抗性种群(Met-R)对甲氧虫酰肼的抗性倍数为4.19倍;交互抗性测定发现,Met-R甜菜夜蛾对毒死蜱、高效氯氰菊酯、虫螨腈、虫酰肼、甲胺基阿维菌素苯甲酸盐等药剂的交互抗性比值在1.05～2.07之间,不存在交互抗性。离体酶活性测定结果表明,Met-R甜菜夜蛾5龄幼虫中肠谷胱甘肽S-转移酶比活力是相对敏感种群(SS)甜菜夜蛾的2.44倍,存在显著性差异,说明谷胱甘肽S-转移酶活性增强可能与甜菜夜蛾对甲氧虫酰肼产生抗药性有关;但Met-R甜菜夜蛾全酯酶催化活性与SS的无显著性差异,说明其抗药性可能与酯酶无关。

Selection for resistance of Spodoptera exigua to methoxyfenozide and preliminary study on the mechanisms of resistance

After 13 generations＇ selection in the laboratory, the methoxyfenozide-selected strain （Met-R） of Spodoptera exigua （Htibner） showed only a 4.19-fold increase in resistance to methoxyfenozide. Met-R showed no cross-resistance to ehlorpyrifos, beta-cypermethrin, chlorfenapyr, tebufenozide or emamectin benzoate, with resistance ratio increases of 1.05-2.07-fold. In vitro biochemical studies showed that GST activity in the midgut of5th instar larvae of Met-R was 2.44 times greater than in larvae of the susceptible strain （SS） , indicating that enhanced GST activity may be associated with the resistance of S. exigua to methoxyfenozide. In contrast, nonspecific-esterase activity in Met-R showed no significant difference from that in SS, suggesting that nonspecific-esterase may not be involved in the resistance.