Granary weevil

Systematic position: The granary weevil (Sitophilus granarius) belongs to the order Coleoptera and the family Curculionidae. It is recognized as one of the most destructive pests affecting stored grains globally, capable of thriving in temperate climates and enclosed storage facilities.

Crops damaged: This pest primarily infests wheat, rye, barley, oats, corn, rice, and buckwheat. It rarely attacks legumes but is highly specialized in destroying stored cereal kernels, making it a critical threat to grain elevators and warehouses.

Biology and life cycle: Adult weevils are 3–4 mm long, dark brown or black, with a characteristic snout. Unlike other grain pests, this species is flightless. A female drills a hole in the grain, lays an egg, and plugs the hole with a gelatinous secretion. The entire larval development occurs inside the kernel, protecting it from many external environmental factors.

Nature of damage and harm: The larvae consume the endosperm, leaving only the hollow grain shell. Infestations lead to substantial weight loss, reduced germination rates, and physical degradation of the grain. Furthermore, the heat generated by the infestation can lead to hotspots, increasing the risk of mold and total grain spoilage.

Control measures: Effective management requires preventing cross-contamination and controlling the storage environment:

• Implementing strict sanitation protocols in warehouses and silos.
• Ensuring grain moisture levels are kept below 13% to hinder larval development.
• Using certified fumigants in airtight storage conditions to eliminate internal infestations.
• Monitoring grain temperature regularly to detect early signs of pest activity.