Rice Weevil and Granary Weevil

Description of rice weevils and granary weevils

The rice and granary weevil are pests of stored grain and seeds. They develop inside whole grain kernels as small, white, wrinkled, grub-like larvae. There is generally no external evidence that the larvae have been eating and growing inside the seed until after about one month when the adult weevil chews through the seed coat and emerges. The adult weevils are 1/8th inch long and have slender, hard-shelled bodies that appear pitted or scarred with tiny holes. They are brown to reddish brown in color. The rice weevil has four faint yellowish spots on the back of the abdomen. The granary weevil is uniformly colored with no spots.

Damage caused by rice weevils and granary weevils

Presence of rice or granary weevils inside the home usually indicates there is infested whole grain or seeds. This may be food seeds or beans in the cupboards, popcorn, saved garden seeds, dried seed decorations, decorative Indian corn, "bean bags," old grain-based mouse bait, or other stored seeds.

Rice and granary weevils are harmless to people, houses, furniture, clothing and pets. They cannot bite or sting and they do not carry diseases. They will not feed on furniture, the house structure or other items. The harm they do is destruction of the seeds they infest and the annoyance of being in the wrong place.

Management of rice weevils and granary weevils

Control requires locating and eliminating the infested whole grain. Small quantities of grain can be "saved" by controlling the weevils with heat or cold. Heating grain to 140 degrees F for 15 minutes or freezing at 0 degrees F for 3 days will kill all stages of weevils in the grain. Larger quantities may require disposal or professional fumigation.

Cupboards or shelves holding infested items should be emptied and thoroughly vacuum cleaned, paying special attention to cracks and corners. Insecticide sprays are not recommended for controlling insects in stored food cupboards. Washing shelves with detergent, bleach, ammonia or disinfectants will not have any effect on insect pests. As a precaution against reinfestation, you may want to store susceptible foods in sealable glass, metal or heavy plastic containers or in the refrigerator or freezer until you are convinced the infestation is gone.

Even when damaged, rice weevils can be identified by the long snout and the 4 pale dots on the wing covers