[The use of stable pyrethroids against Musca domestica in East Germany]

In several European countries and overseas the use of permethrin for the control of Musca domestica has led to resistant populations in a relatively short time. Since stable pyrethroids are desirable alternatives for the control of houseflies being resistant against chlororganic or phosphororganic insecticides the application of these substances should be carefully considered. The first selection tests in the laboratory and tests on natural populations indicate a potential resistance risk in GDR housefly populations. Evaluations of the mechanisms of resistance by using synergists revealed some connection with the more or less widespread resistance against trichlorphon and trichlophenidine. It was concluded that the application of stable pyrethroids against Musca domestica should be avoided as long as possible. Inevitable application should be strictly limited.