Grain weevil is a small, dark beetle that destroys grain. The best-known species (kinds) of grain weevils are the granary weevil, which usually attacks grain stored in granaries; and the rice weevil, which often attacks rice and other grains in the field.
Grain weevils belong to a large group of beetles known as the snout beetles. Grain weevils measure about 1/8 inch (3 millimeters), including their long snouts. Granary weevils do not have wings and cannot fly. But rice weevils have well-developed wings and can fly.
The female grain weevil punctures grains with her snout and lays one egg in each hole. She may lay 200 to 400 eggs over a period of several months. The eggs hatch into tiny, legless grubs (wormlike animals). The grubs eat the inside of the grains and become adults in about a month (longer in cold weather).
Storing grain in clean, dry, tight bins helps control grain weevils. Bins should be cleaned and sprayed before new harvests are stored. Infested grain should be fumigated with a gas that is poisonous to grain weevils.