Granary weevil

The granary weevil (Calandra granaria, formerly Sitophilus granarius) is a significant beetle pest belonging to the Curculionidae family. It is considered one of the most destructive pests of stored grain products worldwide, thriving in warehouses, silos, and mills.

The weevil infests a variety of cereal crops, most notably wheat, rye, barley, rice, and maize. While they prefer whole grains, they can also infest processed grain products, causing substantial economic losses by compromising both the quantity and quality of stored reserves.

The life cycle of the granary weevil involves complete metamorphosis. The female bores a small hole into a grain kernel, deposits an egg, and seals the opening with a plug. The larva develops entirely inside the kernel, consuming the endosperm. Adult weevils are flightless but are remarkably resilient to varying environmental conditions.

The economic damage caused by this pest is primarily internal. Because the larvae feed inside the kernels, the grain often appears intact from the outside until the adults emerge, leaving behind hollowed-out husks. This results in significant weight loss, loss of germination viability, and increased susceptibility to secondary mold growth.

Effective management strategies require a proactive approach to grain storage. Core practices include:

• Strict sanitation and cleaning of storage facilities before new grain arrival.
• Drying grain to a moisture content below 14% to inhibit insect reproduction.
• Monitoring temperatures and using aeration to keep the grain cool.
• Implementing fumigation or contact insecticide treatments when infestations are confirmed.