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以甜菜夜蛾Spodoptera exigua(Hübner)、小菜蛾Plutella xylostella(L.)和棉铃虫Helicoverpa armigera(Hübner)为试虫,通过室内生物测定技术,研究了氮酮、噻酮和N-甲基-2-吡咯烷酮等3种渗透剂对高效氯氰菊酯毒力的影响;利用扫描电镜观察了甜菜夜蛾和小菜蛾4龄幼虫对照组和渗透剂处理组间上表皮超微结构的变化。结果表明:含3.0%N-甲基-2-吡咯烷酮的高效氯氰菊酯对小菜蛾幼虫LD50为0.0074μg/头、毒力系数为2.0,对高效氯氰菊酯增效作用明显,而对其他两种试虫没有增效作用;氮酮和噻酮对高效氯氰菊酯对3种鳞翅目幼虫毒力均无增效作用。甜菜夜蛾对照组上表皮蜡质层和护蜡层清晰可见,渗透剂处理组上表皮护蜡层有不同程度的消失;而小菜蛾对照组和N-甲基-2-吡咯烷酮处理组上表皮护蜡层没有明显变化,只有氮酮处理组上表皮的护蜡层消失。以上结果提示,渗透剂对上表皮护蜡层的影响不是其对高效氯氰菊酯增效作用的机制。
In this study, Azone, thiazone and N-methyl-2 were studied by indoor bioassay using Spodoptera exigua (Hübner), Plutella xylostella (L.) and Helicoverpa armigera (Hübner) - pyrrolidone on the toxicity of beta-cypermethrin. The ultrastructural changes of the upper epidermis of the 4th instar larvae of Spodoptera exigua and Plutella xylostella in the control group and the penetrant-treated group were observed by scanning electron microscopy. The results showed that the β-cypermethrin with 3.0% N-methyl-2-pyrrolidone had a LD50 of 0.0074 μg / head against the Plutella xylostella larvae with a virulence coefficient of 2.0 and a synergistic effect on beta-cypermethrin. However, Synergism; Azone and thiazone have no synergistic effect on the toxicity of beta-cypermethrin to the three species of Lepidopteran larvae. Beet armyworm control group of epidermal wax layer and paraffin layer is clearly visible, penetrant treatment group epidermal paraffin layer to varying degrees disappear; while the diamondback moth control group and N-methyl-2-pyrrolidone treatment group epidermis No significant changes in paraffin layer, only the azone treatment group on the epidermis disappear wax layer. The above results suggest that the effect of penetrant on the wax layer of the epidermis is not a mechanism of its synergistic effect on beta-cypermethrin.