氯虫苯甲酰胺和氟虫双酰胺对不同虫态甜菜夜蛾的毒力作用

采用浸叶法、点滴法、夹毒叶片法、成虫药膜法、饲喂毒营养液法测定了氯虫苯甲酰胺、氟虫双酰胺对甜菜夜蛾卵、2~4龄幼虫、成虫的活性和对4龄幼虫的拒食活性,以明确氯虫苯甲酰胺和氟虫双酰胺对不同虫态甜菜夜蛾的毒力作用。结果表明,两种杀虫剂均不具有杀卵活性,但可以明显降低初孵幼虫存活率;氯虫苯甲酰胺、氟虫双酰胺均对2龄幼虫活性最高,分别为3龄幼虫的1.50、6.17倍和4龄幼虫的22.25、44.95倍,对4龄幼虫胃毒活性分别为触杀活性的14.10、8.44倍;氯虫苯甲酰胺对甜菜夜蛾成虫毒力为氟虫双酰胺的25.53~34.19倍。氯虫苯甲酰胺、氟虫双酰胺对甜菜夜蛾幼虫表现出较强的拒食作用, 至处理后48 h拒食率达到最高, 分别为 82.73%、84.15%,显著高于对照药剂甲维盐各浓度处理,处理试虫虫体皱缩、体节缩短,体重增加率明显低于对照和甲维盐各处理。

Comparison of the toxicity of chlorantraniliprole and flubendiamide to different developmental stages of Spodoptera exigua

The susceptibilities of eggs, 2nd, 3rd, 4th instar larvae and adults and antifeedant effect of Spodoptera exigua to chlorantraniliprole and flubendiamide were investigated using egg-dip method, leaf-dip method, topical application, stomach poison test, residual film and fed poison nutrient solution method. The results indicate that there were no ovicidal activities in the two insecticides, but the survival rates of neonate larvae were decreased with the concentration of the two insecticides increased. The toxicity of two insecticides to 2nd instar larvae was the highest, which were 1.50-, 6.17-fold than the 3rd instar larvae and 22.25-, 44.95-fold than 4th instar larvae. Two insecticides had good oral toxicity to 4th instar larvae of S.exigua, and were 14.10-, 8.44-fold than the contact toxicity, respectively. The activities of the two insecticides to adults indicated that the chlorantraniliprole was higher than flubendiamide with the toxicity ratios were 25.53 to 34.19-fold. The results of antifeedant test showed obvious antifeedant effect to larvae of S.exigua after treatment with the two insecticides. After 48 h, antifeedant ratio reached the maximum, and the ratios were 82.73%, 84.15%. The larvae showed feeding cessation, lethargy and muscle paralysis after treated with two insecticides.