溴氰虫酰胺和氯虫苯甲酰胺对三种鳞翅目害虫的毒力作用比较

为比较溴氰虫酰胺和氯虫苯甲酰胺对甜菜夜蛾、玉米螟和小地老虎的作用差异，采用浸卵法、浸叶法、饲喂毒营养液法等测定了溴氰虫酰胺和氯虫苯甲酰胺对3种害虫的卵、3龄幼虫和成虫的毒力，以及对其3龄幼虫的拒食活性。结果表明，溴氰虫酰胺和氯虫苯甲酰胺均无杀卵作用，但能降低初孵幼虫存活率。溴氰虫酰胺对甜菜夜蛾、玉米螟和小地老虎3龄幼虫的LC₅₀值分别为0.11、0.05和0.13 mg/L，相对毒力分别是氯虫苯甲酰胺的2.8、2.7和5.1倍。溴氰虫酰胺对3种害虫成虫的LC₅₀值分别为0.11、0.09和0.22 mg/L，相对毒力分别是氯虫苯甲酰胺的3.9、3.8和2.7倍。溴氰虫酰胺在亚致死浓度0.10、0.05和0.14 mg/L的剂量下分别对甜菜夜蛾、玉米螟和小地老虎3龄幼虫表现出较强的拒食作用，处理48 h后达到最高，拒食率分别为85.58%、81.91%和86.11%。药剂处理试虫虫体皱缩，体节缩短，体重增加率明显低于对照处理。表明溴氰虫酰胺对3种鳞翅目害虫的毒力作用比氯虫苯甲酰胺好，可作为氯虫苯甲酰胺的替代药品。

Comparison of the bioactivity of cyantraniliprole and chlorantraniliprole against three important lepidopterous pests

In order to compare the bioactivity of cyantraniliprole and chlorantraniliprole against Spodoptera exigua, Ostrinia nubilalis and Agrotis ypsilon, egg-dip, leaf-dip and poison nutrient solution-feeding methods were used to test the toxicity of cyantraniliprole on eggs, 3rd instar larvae and adults, and antifeedant effect on 3rd instar larvae. The results indicated that both of cyantraniliprole and chlorantraniliprole had no bioactivity to eggs, but could reduce the survival rate of larvae. The LC₅₀ values of the cyantraniliprole to 3rd instar larvae of S.exigua, O.nubilalis and A.ypsilon were 0.11, 0.05, and 0.13 mg/L, respectively, and the relative virulence ratio were 2.8, 2.7 and 5.1 fold as that of chlorantraniliprole, respectively. Meanwhile, the LC₅₀ values of the cyantraniliprole to adults of S.exigua, O.nubilalis and A.ypsilon were 0.11, 0.09 and 0.22 mg/L, respectively, which indicated that cyantraniliprole's toxicity was higher than chlorantraniliprole's with the relative toxicity of 3.9, 3.8 and 2.7 fold, respectively. An obvious antifeedant effect on 3rd instar larvae of S.exigua, O.nubilalis and A.ypsilon was observed after treatment with cyantraniliprole under 0.10, 0.05 and 0.15 mg/L sublethal concentrations. After 48 h, the antifeedant ratios reached the maximum, which were 85.58%, 81.91% and 86.11%, respectively. The tested insect bodies were wrinkled, the somite shortened and the rate of weight gaining was significantly lower than the control after treated with cyantraniliprole and chlorantraniliprole. The tests showed that cyantraniliprole had a higher effect than chlorantraniliprole on three lepidopterous pests, and could be a potential replacement for chlorantraniliprole.