How Weevils Get in Your Food
Like other pantry pests, weevils will infest and feed on grains, nuts, beans, cereals, seeds, corn, and other foods. But unlike beetles that live and feed on foods, weevils live and feed inside the food item. The female chews a hole into a seed or grain kernel and deposits an egg inside. Then, she seals up the opening, leaving the egg behind. When the egg hatches (inside the grain or seed), the larva feeds on the food item until it is fully grown. Once fully grown, the adult weevil eats its way out of the grain or seed. The females emit pheromones, so the male weevils will be waiting outside the hole for a female to emerge and immediately seek to reproduce.
Weevil Identification
Weevils are 1/8 inch to 1/4 inch long. Their long snouts most easily distinguish them. They can live up to eight months and venture far from the food initially infested. Weevils lay eggs that turn into larvae that appear like little white grubs.
Rice Weevils
Very tiny, this weevil is only about 1/16 inch long. The adult is dull reddish brown to black, with four reddish-yellow spots on its back. The larvae are soft, white grubs with no legs. Pupae are similar to adults with long snouts, but they are white. The adult rice weevil can fly and lives up to five months, with the female laying up to 400 eggs during her lifetime.
Maize Weevils
Long thought to be simply a larger strain of rice weevil, the maize weevil looks very similar. It is slightly larger, up to 1/8 inch long. And like the rice weevil, it is dull reddish brown to black with four red-yellow spots on its back. However, its coloring is generally darker than that of the rice weevil. The rate of development is slightly slower for the maize weevil than the rice weevil. Maize weevil larvae are soft, white grubs with no legs. Pupae, too, are similar to adults with long snouts, but they are white. And like the rice weevil, the maize weevil can fly.
Granary Weevils
The granary weevil is more cylindrical than the rice or maize weevil and is about 1/5 inch long. Its coloring is similar to the rice and maize weevils: reddish brown to black. At about a quarter of its body length, the granary weevil’s long snout extends down from its head. Its larvae (soft, white grubs without legs) and white pupae are similar to those of the rice and maize weevil. This weevil cannot fly, so you will find it close to the areas it infests. The adults can live up to eight weeks, with the female able to lay up to 200 eggs.
Damage and How to Get Rid of Weevils
The rice weevil is considered the most destructive because of its long life and partly because of its ability to fly. But all weevils can cause extensive damage to stored foods. When they infest grain stored in bins, undisturbed, they can completely spoil the entire batch of food. You are getting weevils in your house because they can be brought in on packaged foods, fly, or crawl in from outside. Once inside, a population can grow and expand to food items stored nearby if the pests are not controlled. Store grains and other weevil-tempting foods in airtight containers, and always throw out any food where you find weevils. You can get rid of weevils by clearing out cupboards where you’ve discovered them and thoroughly cleaning the area using a vacuum before storing food there again. A vacuum can effectively eliminate eggs, larvae, and adult insects. Avoid using chemical treatments to get rid of weevils because most are not safe to use around food.
