Abstract: 【Aim】 To establish the diagnostic doses of deltamethrin, permethrin and lambda-cyhalothrin for detecting resistance in Aedes albopictus in China.【Methods】Insecticide-impregnated papers were made with different concentrations of deltamethrin, permethrin and lambda-cyhalothrin. The susceptibilities of adults of A. albopictus laboratory strain were tested by the standard WHO tube bioassay, and the number of knockdowned individuals at 1 h post treatment and the number of dead individuals at 24 h post treatment were recorded. Log-probit regression, and the LC₅₀ and LC₉₉ values were calculated using Excel 2007 and SPSS20.0 software. The 2-fold LC₉₉ value was used as the diagnostic dose to separate resistant individuals from susceptible individuals. The resistance of a field population of A. albopictus collected from Haikou city to the three pyrethroids was evaluated based on the diagnostic dose determined. 【Results】 The LC₅₀ values of deltamethrin, lambda-cyhalothrin and permethrin to adult A. albopictus (laboratory strain) were 0.00619%, 0.01403% and 0.05009%, respectively, while the LC₉₉ values were 0.05175%, 0.11859% and 0.53165%, respectively. Thus the corresponding diagnostic doses of the three pyrethroids were 0.1035%, 0.2372% and 1.0633%, respectively. Tested with the diagnostic doses of deltamethrin, permethrin and lambda-cyhalothrin, the mortalities of adults of the field population of Haikou were 22.58%, 36.29% and 40.83%, respectively, indicating that the Haikou population has developed resistance to all the three pyrethroid insecticides. 【Conclusion】 The diagnostic doses of three pyrethroids established in this study for A. albopictus can be used as the reference for monitoring insecticide resistance of adults of this mosiquito.

Key words: Aedes albopictus, insecticide, pyrethroids, tube bioassay, diagnostic dose, resistance detection