3种农药对莲藕莲缢管蚜的杀虫活性和安全性

摘要

The toxicity of three pesticides,imidacloprid,acetamiprid and pymetrozine to Rhopalosiphum nympha-eae in Nelumbo nucifera Gaertn.,and their safety to crops,were investigated by indoor incubation and field ex-periment.The results showed that the lethal concentration of 50 percent individuals (LC50 )of imidacloprid,acet-amiprid,pymetrozine was 0.26 mg/L,0.09 mg/L and 1.0 mg/L,respectively,and there was a significant differ-ence among the three pesticides in the toxicity to R .nymphaeae .No damage on the growth of N .nucifera was observed under the experimental dose with the treatment of seed dressing and stem-leaf spraying.The field experi-ments showed that the control efficiency was more than 90% 7 days after application in Fujian,Hunan,Zhejiang, Shandong and Hubei.Residual trails showed that the half-life of imidacloprid,acetamiprid,pymetrozine on the lotus leaf was 2.5-5.9 days,7.4-9.5 days,and 0.8-1.3 days,respectively.Imidacloprid,acetamiprid,and pymetrozine as the easily biodegradable pesticides,remaining in the environment for a short time,are relatively environment-friendly for use.%为筛选防治莲藕莲缢管蚜的理想药剂，比较研究了吡虫啉、啶虫脒、吡蚜酮的杀虫活性、田间防效、作物安全性和残留。结果表明，啶虫脒对莲缢管蚜3日龄蚜虫的 LC50为0．09 mg／L，毒力显著高于吡虫啉和吡蚜酮（LC50值分别为0．26 mg／L 和1．0 mg／L）。湖南、湖北、浙江、福建和山东田间试验结果表明，吡虫啉、啶虫脒和吡蚜酮在15 g／hm2以上有效使用剂量时，药后7 d 对莲藕莲缢管蚜的防治效果均在90％以上。10％吡虫啉可湿性粉剂、5％啶虫脒乳油、25％吡蚜酮可湿性粉剂在稀释250倍及以下剂量时拌种或茎叶喷雾对莲藕植株生长均无药害。残留试验结果表明，吡虫啉在莲叶上的半衰期为2．5～5．9 d；啶虫脒在莲叶上的半衰期为7．4～9．5 d；吡蚜酮在莲叶上的半衰期为0．8～1．3 d。吡虫啉、啶虫脒和吡蚜酮防治莲藕莲缢管蚜安全、高效。