Carbamate Insecticides Resistance Monitoring of Adult Male German Cockroaches, Blattella germanica (L.), in Southern Iran

Abstract

Background: The German cockroach, Blattella germanica L. (Dictyoptera: Blattellidae), has become resistant to many insecticides due to control failures in hospital and student dormitory settings of southern Iran. Objective: This study was thus designed to detect and monitor carbamate resistance in two strains of German cockroach using lethal dose bioassay methods. Methods: Wild dormitory (D) and hospital (H) strains were collected. Adult males were subjected to the jar exposure procedure. A range of concentrations based on the world health organization (WHO) standard concentration of carbamate insecticides (carbaryl, bendiocarb, propoxur) were used. For each insecticide, four to seven different concentrations leading to >0% and propoxur > bendiocarb. The ratio of LD50 in H strain to that of D strain for bendiocarb was about twice that of the other two insecticides indicating that German cockroaches were most susceptible to bendiocarb under both environments. Conclusion: It is concluded that excessive reliance on carbaryl in both D and H settings has led to resistance.

Keywords

• Blattella germanica
• Carbamate
• Insecticide