D.D.T. as a Residual Insecticide against <i>Anopheles maculipennis</i>

Abstract

THE article by Muirhead-Thomson¹ on D.D.T. and Anopheles gamibiœ adds support to my belief that the same conclusions may apply to A. maculipennis varieties. During service in Italy in 1944 and 1945, I was concerned with the effect of D.D.T. in areas where A. maculipennis var. labranchiœ and var. typicus were the common varieties. Mosquito catches, and other observations, made in areas where ‘domestic’ resting places had been treated with 5 per cent D.D.T. in kerosene, suggested that control was not so complete as at first appeared. None of this evidence was conclusive, but it did indicate that the fall in mosquito numbers seen in houses treated with D.D.T. did not represent a comparable reduction in the total mosquito population of the area. It suggested to me a repellent rather than a lethal action of D.D.T.