Zeteki bean weevil

Systematic position. The Zeteki bean weevil (Acanthoscelides zeteki) belongs to the order Coleoptera and the family Bruchidae. It is a significant pest primarily affecting stored and field legume crops, particularly in warm climatic zones where conditions are favorable for its rapid reproduction.

Host plants. This pest primarily targets seeds of the genus Phaseolus, with common beans (Phaseolus vulgaris) being the most susceptible host. It is considered a serious threat to seed quality and can be spread across regions through the trade of infested bean lots, necessitating strict quarantine enforcement.

Biology and life cycle. The life cycle consists of egg, larval, pupal, and adult stages. Females lay eggs on the surface of seeds. Once hatched, the larva bores into the seed, where it spends its entire development cycle. The speed of the cycle is highly dependent on environmental temperature, allowing the insect to have multiple generations per year in storage facilities.

Damage and economic impact. Larvae consume the internal part of the seed, including the germ, which drastically reduces germination rate. A clear indicator of infestation is the presence of small, perfectly circular exit holes on the seed coat. Heavily infested batches exhibit significant weight loss and are often contaminated with frass, rendering the product unmarketable.

Control measures. Integrated pest management (IPM) is essential to combat this weevil. Key strategies include:

• Quarantine inspections of imported legume shipments.
• Use of fumigants (such as phosphine) in storage facilities.
• Prompt harvest of crops to prevent field infestation.
• Low-temperature storage or hermetic storage conditions to inhibit larval growth.
• Regular monitoring of stored grain samples.