Abstract
Tests on effect of insecticides on adults of housefly and German cockroach were carried out by dipping technique. The insecticides employed were as follows : Tech. -DDT. lindane, dieldrin, DDVP, Dibrom, diazinon, ronnel, Baytex, Sumithion, Dipterex, malathion. Adults of housefly and German cockroach were immersed for three minutes in diluted aqueous solution of acetone or ethanol containing a required concentration of each insecticide. Mortality was recorded after 24 hours. Effects of dipping tests were evaluated differently and compared with those of topical application. Effects of DDVP, Dibrom, Dipterex and malathion of dipping were especially lower in comparison with those of topical application. Moreover, the mortality was affected strongly by the susceptibility of insect strain tested. Housefly adults used here showed resistance to organochlorinated insecticides and diazinon of topical application tests and the effectiveness which was commpared with LC_50 of dipping tests was declined in following order : ronnel, Baytex, Dibrom, Sumithion, diazinon, lindane, DDVP, DDT, malathion, dieldrin, Dipterex. German cockroach showed no resistance to insecticides tested (dieldrin, lindane, Baytex, Sumithion, diazinon, ronnel, Dibrom, DDVP, DDT, malathion, Dipterex).
