1. Tropical Pesticides Research Institute, Arusha, Tanganyika.
2. ^*Present address: Department of Biological Sciences, Queen's University, Kingston, Ontario, Canada.

Abstract

THE first report of resistance to dieldrin by the tropical bed-bug, Cimex hemipterus, in East Africa was that by Smith¹. In observations made during the course of the Pare-Taveta Malaria Control Scheme, it was reported² that the bed-bug population was reduced to very low numbers following the first dieldrin spray (first treatment of 80 mgm. dieldrin/sq. ft. followed by subsequent treatments of 40mgm./sq.ft. at eight-month intervals), but 14–19 months after this treatment the bed-bugs were present in sufficient numbers to be considered of nuisance value. In a series of laboratory tests it was shown that whereas bed-bugs from an untreated area were all dead after a seven-day exposure to 0.1 per cent dieldrin using a method suggested by Busvine³, there was only an 18 per cent mortality for a similar exposure time among bed-bugs from the treated area.