Adzuki bean weevil

The Adzuki bean weevil (Callosobruchus chinensis) is a major agricultural pest belonging to the order Coleoptera and the family Bruchidae. It is widely recognized for its devastating impact on various pulses and leguminous seeds stored in warehouses globally.

This beetle primarily infests a wide range of crops including adzuki beans, mung beans, chickpeas, lentils, and peas. While it can infest crops in the field before harvest, it is primarily regarded as a serious storage pest capable of causing total destruction of stored stocks if left unchecked.

The biological cycle begins when an adult female deposits eggs on the surface of the legume seed. Upon hatching, the larva bores directly into the seed coat to feed on the interior tissues. The larval stage, followed by pupation, occurs entirely inside the kernel, shielded from many external environmental factors.

The primary symptom of infestation is the presence of characteristic circular exit holes on the beans, made by emerging adults. These holes indicate that the interior of the seed has been consumed, resulting in significant weight loss, contamination with frass, and a complete loss of germination potential and nutritional value.

Effective management requires a multi-pronged approach:

• Maintaining strict sanitation standards within storage facilities;
• Monitoring temperature and humidity levels to discourage reproduction;
• Utilizing controlled atmosphere storage or cold storage;
• Applying fumigants according to safety regulations for infested batches;
• Implementing airtight storage solutions to prevent further cross-infestation.