Investigation on the resistance of Blattella germanica to five commonly used insecticides in Baiyin in 2024

ZHANG Xuetai; WANG Youjun; ZHANG Jifang; DONG Jinyu

doi:10.19821/j.1671-2781.2025.02.004

Abstract：Objective To understand the resistance level of Blattella germanica to commonly used insecticides in Baiyin,so as to provide a basis for rational use of pesticides and consolidating the achievements of vector control.Methods The cockroaches were collected in key habitats in national sanitary counties or districts and non-national sanitary counties or districts of Baiyin in 2024,and brought back to the laboratory for rearing until the F1 generation.The resistance of male adult B.germanica to five commonly used insecticides was investigated by the residual film method.The types and amount of insecticide in Baiyin from 2021 to 2023 were collected,and Excel 2017 and SPSS 25.0 softwares were used for data processing and analysis.The insecticide resistance of B.germanica in national sanitary counties or districts and non-national sanitary counties or districts was compared using the Chi-square test.Results The resistance of B.germanica to pyrethroids was higher.The median knockdown time(KT50)of cypermethrin,beta-cypermethrin and deltamethrin in national sanitary counties or districts was 3.40,2.14 and 2.02 times than that of non-national sanitary counties or districts,and there were significant differences in resistance between national sanitary counties or districts and non-national sanitary counties or districts(χ2=8.326,7.238,6.414,all P＜0.05).The resistance to dichlorvos and propoxur were low,and there were no significant difference in resistance(χ2=2.264,2.714,all P＞0.05).Conclusion B.germanica in Baiyin has different degrees of resistance to five commonly used insecticides,it is recommended to suspend the use of pyrethroids alone and use low-resistance insecticides.The insecticides should be selected based on the monitoring results of insecticide resistance and strengthen supervision.