Abstract
By topical application, we studied diazinon and malathion susceptibility of 30 F_1 subcolony of houseflies, Musca domestica L., which were established from 30 females collected from a farm in Hokota. The LD_<50>'s of diazinon against the most susceptible and resistant subcolonies were 0.095 and 2.6μg per female fly respectively. When malathion applied at the dose of 10μg per female fly, the mortality of subcolony varied from 0 to 100%. We concluded that susceptibility of houseflies to insecticide varied widely even when they were collected from the same breeding habitat.
