Abstract:Aim To provide insight into biochemical detection of insecticide resistance of mosquitoes and rational use of chemical insecticides,studying the fluctuation of non-specific esterase in different development stages of DDVP-resistant and susceptible Cx.pipiens pallens.Methods The NSE activity of single mosquito was detected by microplate test,using β-Naphthyl cetate as the substrate and fast blue B salt as color agent Results The results showed that the NSE activity changed in different development stages of DDVP-resistant and susceptible strain.IV-instar larvae showed the highest NSE activity level,then declined in pupae stage,adult took the second place,followed by Ⅰ~Ⅲ-instar larvae.The NSE activity of DDVP-resistant strain was higher than that of susceptible strain in all the development stages and significant difference of NSE avtivity was found between Ⅳ-instar larvae and adult.Conclusion Ⅳ-instar larvae or non-blood feeding 3-day-old females can be used for insecticide resistance detection by determination of NSE.And the insecticides should be used at the early larvae stage in mosquito chemical control.