吡虫啉对几种同翅目害虫的触杀毒力测定

Studies on the Contact Tosicity of Imidacloprid to Several Pests of Homoptera

测定我国新研制的杂环类杀虫剂吡虫啉对褐稻虱、棉蚜、麦蚜和菜蚜等同翅目害虫的触杀毒力，并与常用药剂甲胺磷和氧化乐果的触杀毒力进行比较。结果表明，吡虫啉对褐稻虱的触杀毒力明显高于甲胺磷；对棉蚜、麦蚜。

The contact toxicity of imidacloprid,methamidophos and omethoate to rice brown planthopper( Nilaparvat Lugens Stal),cotton aphids( Aphids gossypii Glover),spring grain aphids ( Toxoptera graminum Rondni)and cabbage aphids( Brevicoryne brassicae )were tested by means of immersion and spray in 1993 and 1994.At 24 hafter the application of insecticides,the LD 50 value of imidacloprid was 1 66 ppm to rice brown planthopper while that of methamidophos was 61 67 ppm.The LD 50 value of imidacloprid was 0 38 ppm and that of omethoate was 110 04 ppm to cotton aphids.The LD 50 values of imidacloprid was 0 26 ppm and that of omethoate was 4 28 ppm to cabbage aphids.In other words,the LD 50 value of imidacloprid increased by 37 15 times than that of methamidophos to rice brown planthopper,and the LD 50 values of imidacloprid to the three aphids increased by 289 6,15 6,and 38 9 times than that of omethoate,respectively.At 48 hafter application,the LD 50 values of imidacloprid increased by 46 4 times than that of methamidophos to rice brown planthopper,and increased 334 7,30 4 and 82 3 times than that of omethoate to the three aphids,respectively.