Objective To evaluate the resistance of Culex pipiens pallens to commonly used chemical insecticides in Shandong province, providing the basis for proper and efficient administration of insecticidal chemicals. Methods The WHO bioassay was used to test the resistance of susceptible strains and field populations of Cx. pipiens pallens to 5 kinds of insecticide. Results Of 6 field populations of Cx. pipiens pallens, the resistance indices for DDT, DDVP, malathion, propoxur and deltamethrin were 1.59-28.48, 2.22-15.72, 2.36-5.50, 3.40-6.33 and 8.50-36.00. Conclusion Cx. pipiens pallens in Shandong province has generated different degrees of resistance to the 5 commonly used chemical pesticides. Therefore, appropriate measures should be taken to prevent or delay the emergence and development of insecticidal resistance in mosquitoes.

【Abstract】 Objective To explore the effect of frozen storage on non-specific esterase (NSE) activity of Culex pipiens pallens and provide a basis for the generalization and application of insecticide-resistance detection of mosquito by biochemical method. Methods The NSE activity of single mosquito was determined based on β-naphthalene acetic acid ester (β-naphthyl acetate, β-NA) as substrate and solid blue B salt (fast blue B salt) as developer. Results The NSE activity of DDVP-resistant strain was obviously higher than that of susceptible strain. For the A value of NSE activity from Cx.pipiens pallens after frozen for 0, 7, 14, 21 and 28 days at -20 ℃, the F value of 4 instar larvae of susceptible strain mosquito was 0.7642 by the complete randomized design variance comparison and the F value of 3-day-old adult female of susceptible strain mosquito was 0.7452. The F value of 4 instar larvae of DDVP resistant strain mosquito was 0.1092, and the F value of 3-day-old adult female of DDVP-resistant strain mosquito was 0.1521. All of the P value were greater than 0.05 and no significant difference was found. Conclusion There was no difference between on the NSE activity of 4 instar larvae and 3-day-old adult female of Cx.pipiens pallens after frozen for 28 days, and mosquitoes collected from the field could be taken to the lab for batch determination.