MA Zhuo, ZHOU Xiao-jie, LI Jing, LI Qiu-hong, LIU Ting, ZENG Xiao-peng
Objective To investigate the resistance of Musca domestica to 6 commonly used insecticides in Beijing, China, in 2017, and to provide a scientific basis for rational use of insecticides. Methods Using sweep net or fly trap, the field population of M. domestica was sampled from 6 urban districts in Beijing (Dongcheng, Xicheng, Chaoyang, Haidian, Daxing, and Tongzhou) from August to October, 2017. The micro-drip method was used to determine the resistance of M. domestica to 6 commonly used insecticides, i.e., DDVP, chlorpyrifos, beta-cypermethrin, deltamethrin, lambda- cyhalothrin, and propoxur. Bioassay data were pooled, and probit analysis was conducted with POLO-Plus 2.0 software (LeOra Software Inc., Berkeley, CA) to calculate median lethal dose, slope, and their 95% confidence intervals. Results Varying degrees of resistance level of M. domestica to DDVP, chlorpyrifos, beta-cypermethrin, deltamethrin, lambda- cyhalothrin, and propoxur were observed in the 6 urban districts of Beijing (Dongcheng, Xicheng, Chaoyang, Haidian, Daxing, and Tongzhou). The order of insecticide resistance level, from high to low, was propoxur (>500), beta-cypermethrin (42.80-260.01), deltamethrin (14.53-52.15), DDVP (15.22-31.95), lambda-cyhalothrin (11.83-31.48), and chlorpyrifos (2.59-6.38). Conclusion Musca domestica in Beijing has developed resistance to 6 commonly used insecticides, especially to propoxur and beta-cypermethrin, which we suggest should be suspended. In order to prevent the increasing insecticide resistance of M. domestica, the remaining insecticides should be used rationally according to the results of insecticide resistance surveillance.