Dolichos bean beetle

Systematic position. The Dolichos bean beetle (Callosobruchus dolichosi) belongs to the order Coleoptera and the family Bruchidae. It is a significant agricultural pest known for attacking seeds, particularly those of pulse crops, both in the field and within storage facilities.

Host crops. This pest primarily targets seeds of the genus Dolichos, as well as various types of beans and cowpeas. The high nutritional value of these seeds, combined with their protein-rich composition, makes them ideal hosts for the development of C. dolichosi populations.

Biology and life cycle. The life cycle involves the female laying eggs on the seed coat. Upon hatching, the larva bores into the interior of the seed, where it feeds on the endosperm. After pupation, the adult beetle emerges by cutting a small circular exit hole. Under optimal conditions of heat and humidity, multiple generations can emerge per year.

Nature of damage and economic impact. The infestation leads to the destruction of the embryo and depletion of internal seed reserves. This results in the complete loss of germination potential for seeds intended for sowing and a significant reduction in quality and weight for seeds intended for food processing or export.

Control measures. Effective management strategies include

• maintaining low temperatures in storage facilities to inhibit breeding;
• regular cleaning of machinery and storage areas to remove debris;
• fumigation of infested seed stocks;
• harvesting crops as early as possible to minimize field-to-storage transition of the pest.