雷公藤生物碱制品对小菜蛾和菜青虫的控制效果

测定了雷公藤总生物碱对小菜蛾和菜青虫的室内毒力,以及0.1%雷公藤生物碱乳油对两种害虫的田间防效。结果表明,雷公藤总生物碱对小菜蛾3龄幼虫48和72 h的LC50值分别为228.28和136.67 m g/L,对菜青虫5龄幼虫48和72 h的LC50值分别为307.61和238.18 m g/L;1.0%雷公藤生物碱乳油对小菜蛾的毒杀作用较强,其48和72 h的LC50值分别为69.62和20.35 m g/L,对菜青虫48和72 h的LC50值分别为93.18和44.62 m g/L。250倍稀释的雷公藤生物碱乳油(有效含量为40 m g/L)田间喷雾处理对小菜蛾和菜青虫均具有较好的防治效果,施药后7 d的防治效果分别为82.93%和82.71%,在本试验剂量范围内对作物安全。可见,雷公藤生物碱制品对两种蔬菜害虫控制效果显著。

Control efficacy of alkaloid products from Tripterygium wilfordii Hook against Plutella xylostella (L.) and Pieris rape

The insecticidal activity and control efficacy in the field of two alkaloid products from Tripterygium wilfordii Hook against Plutella xylostella(L.) and Pieris rape were determined in this paper.The results showed that the total alkaloids was very toxic to third instar larvae of P.xylostella(48 h,LC_(50)=228.28 mg/L;72 h,LC_(50)=136.67 mg/L) and fifth instar larvae of P.rape(48 h,LC_(50)=307.61(mg/L);72 h,LC_(50)=238.18 mg/L).1.0% Tripterygium wilfordii EC had a strong toxic effect on P.xylostella and P.rape.The LC_(50) values(48 h and 72 h) were 69.62,20.35 mg/L against P.xylostella and(93.18),(44.62) mg/L against P.rape,respectively.1.0% Tripterygium wilfordii EC applied at 40 mg/L after diluted 250 times in the filed showed control efficacy of 82.93% and 82.71% for larvae of P.xylostella and P.rape after 7 d trial.It is safe to crops at the dosages of the test.1.0% Tripterygium wilfordii EC possesses excellent insecticidal activity to two species of vegetable pests,so it has good development and application prospects.