Abstract:

Objective To investigate the resistance of Culex pipiens quinquefasciatus to chemical insecticides commonly used in heavy disaster areas of the 5·12 Wenchuan Earthquake, Sichuan province, China, and to provide a reference for more scientific and rational selection and use of public health insecticides. Methods Mosquito larvae were collected from heavy disaster areas of the 5·12 Wenchuan Earthquake in Sichuan (experiment group) and non-heavy-disaster area in the urban district of Chengdu (control group). Additionally, standard susceptible strain was obtained from the insectaria of Sichuan Center for Disease Control and Prevention (control group). The dipping method was used to test the resistance of mosquito larvae to insecticides. Data were statistically analyzed using SPSS 17.0 to determine the median lethal concentration (LC₅₀) and resistance grades. Results Compared with the control larvae, the experimental larvae showed significantly high resistance to beta-cypermethrin, with resistance ratios (RRs) of 2925.00 in Beichuan county, 1250.00 in Dujiangyan city, 2375.00 in Qingchuan county, and 1075.00 in Wenchuan county. To deltamethrin, the larvae in Beichuan and Dujiangyan showed high resistance (RR 90.59 vs. 71.77), while those in Qingchuan and Wenchuan showed moderate resistance (RR 14.12 vs. 21.18). All of the experimental larvae showed low resistance to dichlorvos (RRs 9.85, 5.29, 5.90, and 7.05). To Bassa, the experimental larvae showed reduced susceptibility in Beichuan, Dujiangyan, Wenchuan, and Qingchuan (RRs 3.90, 3.12, 3.83 and 1.57). Conclusion Culex pipiens quinquefasciatus larvae developed significantly high resistance to beta-cypermethrin and deltamethrin in heavy disaster areas of the 5·12 Wenchuan Earthquake. According to the usage of insecticides after earthquake, the high insecticide resistance of Cx. pipiens quinquefasciatus was relevant to massive uses of pyrethroid and organophosphorus insecticides for control of harmful insects.

Key words: Earthquake disaster area, Culex pipiens quinquefasciatus, Linear regression, Insecticide resistance, Insecticide selection

摘要：

目的 了解四川省5·12汶川大地震极重灾区致倦库蚊对常用化学杀虫剂的抗药性水平,为指导今后在灾区更加科学、合理地选择和使用卫生杀虫剂提供依据。方法 实验组致倦库蚊幼虫采自四川省汶川地震极重灾区,对照组试虫分别来自非地震极重灾区成都市城区和四川省疾病预防控制中心昆虫饲养室饲养的标准敏感品系。采用生物测定幼虫浸渍法,获得的数据经SPSS 17.0软件进行统计学分析得到半数致死浓度(LC₅₀)值和抗性级别。结果 北川县、都江堰市、青川县和汶川县的致倦库蚊幼虫均对高效氯氰菊酯产生了极高抗性,抗性倍数分别为2925.00、1250.00、2375.00和1075.00倍;北川县和都江堰市试虫对溴氰菊酯产生了高抗性,抗性倍数分别为90.59和71.77倍;青川和汶川县试虫产生了中抗性,抗性倍数分别为14.12和21.18倍;所有实验组试虫均对敌敌畏呈现出低抗性,抗性倍数分别为9.85、5.29、5.90和7.05倍;北川县、都江堰市和汶川县试虫对仲丁威敏感性降低,抗性倍数分别为3.90、3.12和3.83倍;青川县试虫呈现出敏感性,抗性倍数为1.57倍。结论 5·12地震灾区各地致倦库蚊幼虫对常用卫生杀虫剂中的高效氯氰菊酯和溴氰菊酯产生了极高抗药性,结合地震灾区灾后杀虫剂的使用情况,推测与地震发生后大量使用拟除虫菊酯类和有机磷类杀虫剂进行有害昆虫治理有关。

关键词: 地震极重灾区, 致倦库蚊, 直线回归法, 抗药性, 选择杀虫剂