印楝素对不同龄期茄二十八星瓢虫的毒力及田间防效  

Laboratory Toxicity and Field Efficacy of Azadirachtin to Henosepilachna vigintioctopunctata (Fabricius) in Different Instars

作　　者：李兆防[1] 

机构地区：[1]山东省菏泽学院资源与环境系,菏泽274000

出　　处：《中国蔬菜》2009年第10期55-58,共4页China Vegetables

摘　　要：室内毒力测定结果表明:印楝素对茄二十八星瓢虫的毒力随着龄期的增加而减弱。施药后24h和48h,0.3%印楝素乳油(EC)对1～2龄期幼虫的LC50都小于0.2mg.L-1,对3～4龄期幼虫的LC50都小于1.0mg.L-1,成虫对印楝素的敏感性明显降低,施药后24hLC50为2.1227mg.L-1。田间试验结果显示:0.3%印楝素EC400～800倍液对茄二十八星瓢虫幼虫药后7d的防效达91.17%以上,400～600倍液对茄二十八星瓢虫成虫药后7d的防效达81.20%以上,在生产上防治幼虫时建议使用浓度为600～800倍液,防治成虫时建议使用浓度为400～600倍液。Testing result in laboratory showed that the toxicity of azadirachtin to Henosepilachna vigintioctopunctata was deducted with the increase of instars. The larva in 1 - 2 instar was the most sensitive, both of LC50 values were less than 0.2 mg·L^-1. LC50 of azadirachtin to the 3 -4 instar larva was less than 1.0 mg·L^-1. The toxicity to the adult was decreased obviously, it＇s LC50 was 2. 122 7 mg·L^-1 in 24 h. In the field, the effect of azadirachtin against larva was over 91.17 % at the 7 th day at 400 - 800 times, it suggested the insecticide could be applied at 600 - 800 times in farming practice, the effect of azadirachtin against adult was over 81.20 % at the 7th day at 400 -600 times, it suggested the insecticide could be applied at 400 -600 times.

关 键 词：印楝素 茄二十八星瓢虫 毒力 田间防效 

分 类 号：S482.3[农业科学—农药学]