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 Study the changes of acetylcholinesterase (AChE) activity in different strains of adult male and female Culex pipiens pallens, and provide a basis for the insecticide?resistance detection of mosquitoes by biochemical method. Methods The AChE activity of single mosquito was determined, and acetythiocholine iodide (ATch) as the substrate and 5, 5′?dithio?bis (2?nitrobenzoic acid) (DTNB) as the developer. The insensitivity of AChE to Propoxur was assayed. Results The AChE activity of anti?DDVP (Rd) and anti?Propoxur (Rp) strains of Cx.pipiens pallens was significantly higher than that of susceptible (S) strains, however, the AChE activity of anti?Cypermethrin (Rc) strains was similar to that of S strain. The individual frequency of insensitive AChE of Rd strain and Rp strain was significantly higher than that of S strain, but that of Rc strains was similar to S strain. For S, Rd, Rp and Rc strains, the AChE activity of 3?day?old female mosquito was higher than that of 3?day?old male mosquito. Conclusion The resistance of mosquitoes could be judged by the determination of AChE activity, but a criterion should be different for the male and female 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.

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 onβ-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 wa...更多s 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.

Objective:To explore simple and sensitive technic for insecticide resistance detection and early prediction.Methods:Microplate test was used to detect non-specific esterase(NSE) of single Cx.pipeins pallens of laboratory and field population,using β-Naphthyl acetate as the substrate and fast blue B salt solution as the colour agent.Results:The NSE level was highest in anti-DDVP strain,followed by anti-propoxur strain and anti-DDVP degenerated strain,while the level was similar between anti-cypermethrin and susceptible strain.Three field collected Cx.pipiens pallens populations have 4.15-9.36 fold higher resistance against DDVP and 1.02 - 3.81 fold higher resistance against propoxur than susceptible mosquito,and their NSE level was also higher than susceptible strain.Conclusion:Microplate test for NSE can be used for the detection of resistance against Op and carbamate insecticides.The method is easy and rapid to perform with high precision and objective results.Resistance frequency and mechanism can be detected at the same time,so early prediction of resistance and working out resistance management measure is possible.