关键词: 三带喙库蚊, 抗药性, 浸渍法, 半数致死浓度

Abstract:

Objective To determine the current resistance of Culex tritaeniorhynchus, vector of Japanese encephalitis (JE), to commonly used pesticides in Suzhou city, Jiangsu province. Methods Using the dipping method, the median lethal concentration (LC₅₀) values of deltamethrin, betacypermethrin, permethrin, biothrin, dichlorovos and propoxur were measured for the field population of Cx. tritaeniorhynchus in Suzhou city. Results The LC₅₀ values of deltamethrin, betacypermethrin, permethrin, biothrin, dichlorovos and propoxur for Cx. tritaeniorhynchus were 0.0424, 0.1137, 0.2659, 0.6698, 2.4691 and 7.7017 mg/L, respectively. Intermediately resistant to biothrin, the strain was highly resistant to the other five agents with resistance ratios of more than 50, even 100, to the three pyrethroids. Conclusion In view of the low or higher resistance of Cx. tritaeniorhynchus to multiple pesticides, environmental and biological strategies in conjunction with auxiliary chemical approaches should be deployed for better control of this vector. Administration of pesticides and rational agricultural planning should be carried out based on the big picture. In the event of skyrocketing mosquito density or occurrence of JE epidemic, pesticides should be scientifically distributed and chemical control approaches intensified.

Key words: Culex tritaeniorhynchus, Insecticide resistance, Dipping method, Median lethal concentration