广西不同地区小菜蛾对杀虫剂的敏感性研究

采用浸叶法在室内测定了广西5个菜区的小菜蛾种群对13种杀虫剂的敏感性.结果表明,这5个小菜蛾种群对印楝素和氟虫腈的敏感性最高,LC50值在0.08～0.26 mg/L之间;对苏云金杆菌、多杀菌素、溴虫腈、阿维菌素和定虫隆也具有较高的敏感性,LC50值在0.30～16.39 mg/L之间;而对辛硫磷、杀虫双、毒死蜱和敌敌畏的敏感性较低,LC50值在319.74～8 133.98 mg/L之间;对灭多威和杀螟丹的敏感性极低,已无法建立这两种杀虫剂对南宁安吉和石埠种群的毒力回归方程.不同地区小菜蛾种群对苏云金杆菌和毒死蜱的敏感性差异最大,超过6倍;其次为灭多威、杀虫双和定虫隆,种群敏感性差异达4～6倍;而不同种群对辛硫磷和溴虫腈的敏感性几乎没有差异.

Study on susceptibility of Plutella xylostella (L.) to insecticides in different areas of Guangxi

Five populations of Plutella xylostella(L.) were collected from different areas in Guangxi province and their susceptibilities to 13 insecticides were tested by leaf dipping method in laboratory.The results showed that the five populations were the most sensitive to azadirachtin and fipronil,the values of LC_(50) were from 0.08 to 0.26 mg/L,and were also sensitive to Bt,spinosad,chlorfenapyr,abamectin and chlorfluazuron,the values of LC_(50) were from 0.30 to 16.39 mg/L.The five populations had low susceptibilities to phoxim,dimehypo,chlorpyrifos and dichlorvos,the values of LC_(50) were from 319.74 to 8 133.98 mg/L.The toxicity regression equation of methomyl and cartap for Anji and Shibu population could not be established,suggesting the two populations had developed high resistance to the two insecticides.The susceptibilities of the five populations to Bt and chlorpyrifos had over 6-fold difference,and 4~6 fold to methomyl,dimehypo and chlorfluazuron.The susceptibilities of the five populations to phoxim and chlorfenapyr were almost at the same.