Survey on the sensitivity and resistance of Culex pipiens pallens larva to seven kinds of insecticide

Objective To investigate the resistance of Culex pipiens pallens larva to insecticides in Jiangsu Province and provide scientific evidence for control.Methods Larva immersion method.Results The lab population was the most susceptive with LC50 of 0.001 3 mg/L to deltamethrin,0.003 8 mg/L to beta-cypermethrin,0.027 7 mg/L to permethrin,0.181 3 mg/L to esbiothrin,0.018 3 mg/L to DDVP,0.096 8 mg/L to propoxur and 0.000 4 mg/L to temephos.The highest resistance ratio of insecticide was 200 in Nanjing,Xuzhou,Lianyungang and Wuxi.Conclusion In Jiangsu Province C.pipens pallens have developed different resistance to DDVP,temephos,deltamethrin,beta-cypermethrin and propoxur.It is necessary to use the result of survey to prevent the resistance from developing.