Control of insects attacking maize on the cob in crib stores

Abstract

The climatic conditions in Kenya normally prevent maize from drying out sufficiently in the field to allow immediate shelling. At harvest time the husk is removed and the maize on the cobs is stored in cribs until dry enough for shelling and delivery. For this and various other reasons the harvested crop is often kept in this manner for six to eight months or even longer. During this storage time on the farm before any control methods were introduced, ideal conditions existed for many pests to increase to large numbers causing considerable losses in weight and quality. In 1952 the Agricultural Department of Kenya made an investigation (unpublished) of losses in crib storage. Six untreated farm cribs in different districts were shelled out after four months, and six further untreated cribs were shelled out after six months. After correction for changes in moisture content the average weight loss during storage was found to be 9.6 per cent after four months and 23.1 percent after six months. Calandra oryzae L. and sitotroga cerealella Olivo attack the growing crop, but build up mainly in the stores. From the cribs and stores these pests may spread to adjoining maize fields and to other grain crops such as wheat, barley and sorghum. The importance of reducing these enormous losses and preventing the pests from contaminating the growing crops has long been realized