Investigations of the chemical control of insect pests of cotton in central Africa. III.—Field trials

Abstract

Field trials in 1958–62 at Gatooma Research Station, Rhodesia, in which carbaryl, DDT, endrin and endosulfan were compared for controlb of insect pests of cotton, confirmed earlier laboratory results which showed that larvae of Diparopsis castanea Hmps. were more susceptible to carbaryl than those Heliothis armigera (Hb.) but that the latter were more susceptible to DDT. Counts of larvel populations showed that neither insecticide used alone could control the bollworm complex statisfactorily. The results indicated that optimum control could best be achieved by applying one or other insecticide as appropriate after inspection of the crop to determine the level of insects attack at diffetent stages during the seasons, rather than by use of mixtures of both insecticides. It is recommended that dimethoate should be added to either of the insecticides for aphid and red spider mite control when required.