House Fly Residual Control By the Synthetic Pyrethroid, Permethrin, 1978

Residual effectiveness of 4 permerhrin (37% EC) concentrations (0.0625, 0.125, 0.5 and 1.0% Al) and a 0.5% methoxychlor (25% EC) standard against house flies was assayed on finished and unfinished wood and metal sur-faces, exposed and unexposed to the external environment. Prefinished and unfinished wood (2x8 ft) and painted and unpainted galvanized metal (1x6 ft) panels were subdivided into equal sections corresponding to an untreated control, 4 permerhrin concentrations and the methoxychlor standard, respectively, with untreated zones between each. Appropriate panel sections were sprayed to the point of run-off and subsequently exposed, i.e. placed in direct sunlight, or unexposed, i.e. retained inside the laboratory, to the external environment. Residual effectiveness, measured by KT5Q, was assayed at weekly and biweekly intervals by placing 2 groups of 10 2-day-old house flies (USDA Orlando Strain), covered with inverted petri dishes, on each treatment surface. Knockdown was recorded at 5-min intervals for a total of 60 min. Data, corrected for control morbidity, were anal/zed by log-probit regression analysis and KTJQ’S, to the nearest minute, computed.