Insecticide Resistance in the Cocoa Capsid, Distantiella theobroma (Dist.)

Abstract

THE first large-scale trials with γ-BHC against the cocoa capsids Sahlbergella singularis Hagl. and Distantiella theobroma (Dist.) in Ghana were made in 1954¹. The level of capsid control achieved, and the resultant crop yields of cocoa, were so outstanding that the use of this insecticide in recent years has been countrywide. Aldrin and endrin have also been used successfully and the control reported by Armstrong² as having been obtained with amounts of insecticide as low as ½ oz. active ingredient (a.i.) per acre is ample evidence that capsid strains, tolerant or resistant to chlorinated hydrocarbon insecticides, were unknown in Ghana in 1961. Now, however, capsids resistant to γ-BHC have been found on a plot of Amelonado cocoa at Pankese Cocoa Station, near Nkawkaw.