Abstract:

Objective To determine the current resistance of adult Culex pipiens pallens to commonly used pesticides in Jiangsu province, providing the evidence for better mosquito control. Methods The exposure tube method recommended by WHO was applied to measure the median lethal concentration (LC₅₀) for adult mosquitoes. Results The LC₅₀ for field-collected adult mosquitoes in Nanjing, Xuzhou, Lianyungang, Wuxi, Nantong and Huai’an were 0.0173%, 0.0756%, 0.0487%, 0.0070%, 0.0055% and 0.0150% to deltamethrin respectively, and 0.2128%, 0.2711%, 0.1130%, 0.1579%, 0.0504% and 0.0734% to permethrin, respectively. The LC₅₀ to betacypermethrin for field populations in Nanjing, Xuzhou, Lianyungang, Wuxi, Nantong, Huai’an and Suzhou were 0.0224%, 0.0420%, 0.0843%, 0.0023%, 0.0114%, 0.0180% and 0.0108% respectively. The LC₅₀ for Nanjing population to dichlorovos and propoxur were 0.0119% and 0.0129%, while the values for Nantong population to dichlorovos and propoxur were 0.0046% and 0.0077%, respectively. All of tested mosquitoes were intermediately to highly resistant to deltamethrin, with resistance coefficients greater than 100 times in Xuzhou and Lianyungang; lowly to highly resistant to betacypermethrin, with the resistance coefficient up to 94.7 times in Lianyungang in contrast to 2.6 times in Wuxi; and lowly to intermediately resistant to permethrin, with resistance ratios ranging from 11 to 15 times in Nanjing and Xuzhou, and 2.8 times in Nantong. Nanjing population were lowly resistant to propoxur (2.8 times) and sensitive to dichlorovos, while Nantong strains were susceptible to both propoxur and dichlorovos. Conclusion For adult mosquito control in Jiangsu province, the application of deltamethrin and betacypermethrin should be reduced along with increased administration of carbamates, such as propoxur, and organophosphorus pesticides such as dichlorovos. The findings here address consideration and integrated planning to chemical adult mosquito control for delaying or reducing the occurrence and development of pesticid resistance.

Key words: Culex pipiens pallens, Insecticide resistance, Exposure tube method, LC₅₀

摘要：

目的 了解江苏省淡色库蚊成蚊对常用杀虫剂的抗药性现状，以有效指导淡色库蚊的防治。方法 采用成蚊接触筒法测定LC₅₀。 结果 江苏省南京、徐州、连云港、无锡、南通和淮安市淡色库蚊现场种群成蚊对溴氰菊酯的LC₅₀分别为0.0173%、0.0756%、0.0487%、0.0070%、0.0055%和0.0150%，对氯菊酯的LC₅₀分别为0.2128%、0.2711%、0.1130%、0.1579%、0.0504%和0.0734%，南京、徐州、连云港、无锡、南通、淮安和苏州市淡色库蚊现场种群成蚊对高效氯氰菊酯的LC₅₀分别为0.0224%、0.0420%、0.0843%、0.0023%、0.0114%、0.0180%和0.0108%，南京和南通种群成蚊对敌敌畏的LC₅₀分别为0.0119%和0.0046%，对残杀威的LC₅₀分别为0.0129%和0.0077%。所测种群对溴氰菊酯均产生了中等及其以上程度的抗性，其中徐州和连云港种群抗性倍数均在100倍以上；对高效氯氰菊酯呈低抗至高抗，其中连云港种群的抗性高达94.7倍，无锡种群的抗性仅为2.6倍；对氯菊酯呈低抗至中抗，其中南京和徐州种群的抗性倍数为11～15倍，南通种群抗性倍数为2.8倍；南京种群对残杀威低抗(2.8倍)，南京种群对敌敌畏、南通种群对敌敌畏和残杀威均敏感。 结论 江苏省在成蚊防治中，应减少溴氰菊酯和高效氯氰菊酯的使用，可增加敌敌畏等有机磷类和残杀威等氨基甲酸酯类杀虫剂的使用；在进行成蚊化学防治时，要从全局考虑，做好杀虫剂使用的整体规划，以延缓或减少害虫抗药性的发生发展。

关键词: 淡色库蚊, 抗药性, 接触筒法, 半数致死浓度