Efficacy of insecticides in the approved concentration against German cockroach, Blattella germanica in harborage choice tests

Abstract

House-fold pesticides were certificated by the Ministry of Health and Welfare with approved concentration against German cockroaches. In choice tests with insecticide-treated harborages, Permethrin EC was not produced sufficient efficacy even double concentration than the approved concentration. This was due to repellent activities of the German cockroaches. They avoid the residua of Permethrin. Diazinon EC and MC, Fenitrothion MC and Cholorpyrifos-methyl EC were effective at the approved concentration. Microencapsulated formulations of Diazinon and Fenitrothion were more effective than emulsifiable concentration of those insecticides at the same concentration. Cholorpyrifos-methyl EC was the most effective against German cockroaches in the scope concentrations applied.