Research on the Correlation between Propoxur Resistance of Culex pipiens pallens and Esterase Activity

Objective: to detect the resistance index and esterase activity of each generation of propoxur-resistant Culex pipiens pallens and analyze the relationship between resistance and esterase. Methods: WHO bioassay and micro-plate methods were employed for the detection. Results: The resistance index of C.p.pallens increased to 11.26 after 43 -generatuion's selection by propoxur compared with the susceptible strain. The AchE average inhibition rate of the resistant mosquitoes decreased, and the individual frequency of those with inhibition rate no less than 30% increased, with the extension of generations, showing a correlation. The activity of non-specific esterase (NSE) became strengthened, and the individual frequency of the mosquitoes with OD value no less than 0.9 increased gradually, with the extension of generations, consistent basically with the results of the bioassay. Conclusion: The activity of AchE and NSE shows a correlation with propoxur resistance.