Resistance of Blattella germanica to five kinds of insecticides in Shandong Province

Objective To study the resistance of Blattella germanica to common used insecticides in Shandong Province,and provide evidence for using insecticides scientifically and reasonably.Methods Residual film method.Results The resistance ratios of seven field-collected strains to cypermethrin,deltamethrin,beta-cypermethrin,acephate and propoxur were 3.57-37.99,2.11-28.49,1.83-8.42,1.37-7.44 and 0.84-1.87 respectively.The resistance ratios of deltamethrin were high in Jinan,Zibo,Dezhou and Qufu for field-collected strains.The resistance also reached the high level to cypermethrin in Jinan,Zibo and Dongying for three field-collected strains.Conclusion Currently,different resistance levels to common insecticides have been developed in seven geographic populations of Blattella germanica within Shandong Province.Among the five commonly used insecticides,the resistance levels to cypermethrin and deltamethrin are the highest,followed by beta-cypermethrin and acephate,and the resistance levels to propoxur are low.