关键词: 德国小蠊, 抗药性, 抗性消退

Abstract: Objective　To investigate the levels of resistance and the resistance stability of Blattella germanica to five commonly used insecticides, i.e., beta-cypermethrin, chlorpyrifos, acephate, propoxur, and deltamethrin, in Fengtai district, Beijing, China.Methods　The B. germanica used in this study was the first filial generation (F1 generation) and that was bred in the laboratory followed by one-year normal feeding. The insecticide film method recommended by the World Health Organization was used to determine the median knock-down time (KT50) and the corresponding 95% confidence interval (95%CI), knock-down rate, and mortality rate of B. germanica exposed to the five commonly used insecticides and to assess the levels of resistance and the resistance abatement of B. germanica. Results　The mean coefficients of resistance (R/S) of the F1 generation of B. germanica to beta-cypermethrin, acephate, deltamethrin, propoxur, and chlorpyrifos were 7.91, 1.90, 30.52, 4.56, and 2.06, respectively. The rates of resistance decline in B. germanica after one-year exposure to the five commonly used insecticides were 42.82%, 49.70%, 74.77%, 56.51%, and -24.19%, respectively. Conclusion　Blattella germanica has developed different levels of resistance to the five commonly used insecticides in Fengtai district, Beijing. After feeding for one year in the laboratory, the rates of resistance of B. germanica declined for more than 40% for all insecticides except chlorpyrifos.

Key words: Blattella germanica, Insecticide resistance, Resistance abatement