Granary Weevil

Granary weevils (Sitophilus granarius) are significant pests of stored grains including corn, rye, barley, wheat, rice, and occasionally feed on macaroni and spaghetti. They readily infest sunflower seeds, bird seed, ornamental corn, and whole grain based rodent bait

The granary weevil adults are cylindrical, 3/16-inch in length with a distinct snout extending downward about one quarter the length of the body. They are shiny red-black with ridged wing covers and oval pits on the thorax. The larvae are soft, white, fleshy, legless grubs with a tan head. The egg, larva, and pupa all live inside the grain kernels and are rarely seen in infested products. When disturbed, the adults will feign death by drawing

in their legs close to the body, falling and remaining silent.

The adults do not fly but may walk great distances inside warehouses and homes. Granary weevils are found almost exclusively in grain products and are usually transported inside food packaged at the processing plant. The weevils may also be found on the outside of pallets containing food products and between boxes and bags of food on palletized cargo. The increased use of air-tight plastic or foil bags and pouches has minimized granary weevil infestations during transit and storage. It is important to find the infested grain and destroy it before implementing any control measures. Whole grains such as popcorn, decorative seed displays, Indian corn, and “bean bags” filled with whole grains are all potential sources of infestation. Small quantities of infested grain can be heat-sterilized in the oven.