Resistance of Culex pipiens pallens and its control countermeasure

Objective To learn current situation of Culex pipiens pallens resistance to normal used insecticides,and provide scientific information for using insecticides reasonably. Methods Immersion method.Results The LC50 of Culex pipiens pallens to DDVP,malathion,deltamethrin,cypermethrin were 0.820 9,0.161 6,0.006 4,0.008 6 mg/m3.In contrast with standard sensitive strain,relative resistance folds were 18.7,2.2,33.7 and 29.8 respectively.Conclusion Culex pipiens pallens have had resistance to the above four kinds of insecticides to some degree.Its resistance to deltamethrin is the highest,the second is cypermethrin.Its resistance to malathion is the lowest and still in sensitive stage.