3种杀虫剂对中稻田白背飞虱及捕食性天敌群落的影响

摘要

采用室内毒力测定、田间试验和系统调查方法研究了3种杀虫剂对中稻田白背飞虱及捕食性天敌群落的影响，旨在提高水稻白背飞虱的化学防治效率，减少农药对环境的污染，保护天敌对害虫的自然控制作用，为水稻白背飞虱的综合治理提供依据。研究结果表明，阿维菌素、吡蚜酮和毒死蜱3种杀虫剂对白背飞虱3龄若虫均有较高的室内毒力，LC50分别为0．3391、0．8960和4．7147 mg／L，说明安徽省桐城市白背飞虱种群对这3种药剂尚未产生较高的抗药性。阿维菌素对白背飞虱的田间防治效果较差，毒死蜱药后3 d 即达到较好的防治效果，但持效期较短。吡蚜酮对白背飞虱有很好的防治效果，药后7 d 和14 d 的防效分别达到90．94％和89．94％，且对捕食性天敌群落影响较小，有助于保护和加强天敌的自然控制作用，是防治中稻田白背飞虱较理想的药剂。%In order to increase the chemical control efficiency against Sogatella furcifera ,reduce insecticide pollu-tion in the environment and protect the control effects of natural enemies,so as to provide basis for IPM of S . furcifera in rice fields,the effects of three insecticides on S .furcifera and predatory natural enemy community in mid-season rice fields were investigated by toxicity test in laboratory,field experiment and systematic survey.The results showed that abamectin,pymetrozine and chlorpyrifos had relatively high toxicity to 3rd instar nymph of S . furcifera in laboratory,with the LC50 value of 0.339 1 mg/L,0.896 0 mg/L and 4.714 7 mg/L,respectively,in-dicating the population of S .furcifera in Tongcheng City,Anhui Province had not developed evident resistance to the three insecticides.The field control effect of abamectin on S .furcifera was not satisfied and that of chlorpyri-fos was relatively high in three days.Pymetrozine had satisfactory field control effect on S .furcifera with control efficacies of 90.94% (7 days after treatment)and 89.94% (14 days after treatment),respectively.In the mean-time,pymetrozine had minor negative impact on predatory natural enemy community,which was helpful to pro-tect and increase the control effects of natural enemies.Therefore,pymetrozine is a candidate insecticide that can be recommended for S .furcifera control in mid-season rice fields.