Observations on doubly resistant Anopheles aconitus Dönitz in Java, Indonesia, and on its amenability to treatment with malathion.

The development of resistance by a single vector population to the two main insecticides (DDT and dieldrin) used in malaria eradication programmes is as yet a comparatively rare event, but one of a potentially serious nature when it does occur.This paper describes the background of one such instance-double resistance by Anopheles aconitus in Java-and gives the results of observations made on this mosquito population, including its reaction to sprayed structures.Judged on the basis of the mortality produced and of the reduction in biting in sprayed structures, DDT was found to have little effect on A. aconitus. Malathion, on the other hand, gave fairly satisfactory results under the conditions prevailing in the experimental area.