DDT Residual Sprays Applied in Buildings to Control Anopheles quadrimaculatus1

Abstract

DDT residual sprays were applied to the interior of buildings in two 9-sq.-mile areas near Stuttgart, Ark., to determine duration of effectiveness against A. quadrimaculatus. One area was sprayed at the rate of 208 mg. of DDT per sq. ft. and the other at the rate of 56 mg. per sq. ft. Counts in the treated buildings and in untreated buildings in similar areas were maintained from June to Oct. Reduction of mosquitoes in the heavily treated buildings was 99% and in the lightly treated buildings 91% throughout the entire season. Larval counts indicated reductions of 63 and 57%, respectively, in the heavily and lightly treated areas.