Abstract
The susceptibility of 1 laboratory and 4 field strains of adult bedbugs, Cimex lectularius, to 5 insecticides including 2 organophosphates (diclorvos, fenitrothion), 2 pyrethroides (phenothrin, permethrin) and 1 carbamate (propoxur) was examined by contact methods and topical application methods. The propoxur was effective against all the bedbug strains. Diclorvos also showed considerable fast-acting lethal effects and residual activity. On the other hand, pyrethroides had little insecticidal activity under these experimental conditions. These experiments suggest that there is a significant variation in susceptibility among 4 field strains that may relate to the development of insecticide resistance. Especially, Chiba strain showed significantly lower susceptibility than other 3 strains, Toyama01, Toyama08 and Ishikawa. Laboratory tests of heat application showed lethal effects and 1 min of exposure to hot air of >40°C or steam was enough to achieve 100% mortality for bedbugs.
