Study on the density and insecticide resistance of cockroaches in Nanjing City

ZHANG Shou-gang; XIONG Li-lin; SUN Yan-qun; WU Qi-xin; WANG Chong; LU Mo-yuan

Abstract：Objective To analyze the density dynamics and insecticide resistance of cockroaches in Nanjing City.Methods The distribution of cockroach was investigated with cockroach paste method,and insecticide resistance of cockroaches was determined with drug film method.Results Cockroaches were mainly Blattella germanica,Periplaneta fuliginosa and Periplaneta americana.Blattella germanica was the dominant species and its proportion was 98.4％ in 2014.The highest cockroach densities occurred in catering services and famers markets.The density peak of cockroach appeared from July to September,and the highest density was 4.733 insects per sheet in July in 2012.The inter-annual distribution of cockroaches first increased slightly,followed a downward trend from 2011 to 2015,and the peak of cockroach density and infestation rate were 2.213 insects per sheet and 32.454％ in 2014.The population of Blattella germanica evolved 12.16、12.46、19.47、4.22、5.48 and 1.04 folds resistance to beta-cypermethrin,dehamethrin,imidacloprid,acephate,chlorpyrifos and propoxur.Conclusion In recent years,the cockroaches have seriously infested.Blattella germanica was the dominant species.The density peaks appeared in summer and autumn.Blattella germanica population developed high resistance to beta-cypermethrin,dehamethrin and imidacloprid,low resistance to acephate.