Rice Weevils

Image via flickr by Noor Kadir (rana)

One of the tiniest insect pests and a bane for farmers, rice weevils can ruin your day when you find them in your pantry or cellar. Take a look at our thorough guide on how to get rid of rice weevils and everything else you should know about them.

What Are Rice Weevils?

Rice weevils are a species of weevil from the Sitophilus genus, which includes several weevil species that feed on dry food. Unlike many similar species, such as the granary weevil, rice weevils can fly. While they are not pleasant to have around, you can at least be relieved that they are not dangerous or harmful. They do not bite or sting, they do not spread diseases, and they do not damage other things besides obvious food.

What Do Rice Weevils Look Like?

Rice weevils are fairly distinct insects but don’t expect to spot their features without a magnifying glass easily. They are tiny, only reaching up to an eighth of an inch. Their dark bodies are reminiscent of a small beetle. They have six evenly-spaced legs, and a long, curved extension from their heads called a rostrum, which is like a sealed beak with mouthparts at the tip. They have two short antennae splitting laterally from the rostrum bent in front of the eyes.

One exciting aspect of rice weevils is their color. While they look brown from afar, this color blends in with four reddish-orange patches on their sides. However, rice weevils are so small that adults can burrow inside a single grain of rice, so the human eye usually can’t see this exact coloration without a microscope.

Where Do Rice Weevils Live?


Image via Flickr by Charles Haynes

Rice weevils are distributed through all warm parts of the world, with less frequency or no populations in colder climates. Most colder areas, such as northern Europe, have wheat weevils instead, which are more tolerant of the cold. Specifically, rice weevils will look for any large, consistent source of food, such as bags of rice. They will stay in this one source, similar to an established ant colony.

Rice weevils are particularly fond of rice, because of how the grains act like tiny habitats for their larvae. A weevil can chew a hollow space in a single grain, lay eggs inside, and then the hatched larva can eat their way out as they grow. For these reasons, they also enjoy dry corn and seeds.

Problems With Rice Weevils

Since rice weevils need dry, starchy food, they are primarily a stored product pest. They are an issue in warehouses, grain silos, farms, processing plants, and storage facilities. However, they can grow fond of the average home if it has dry starch in easy reach. What’s more, their short life and breeding cycles mean that they can populate quickly.

When females chew holes in food and insert an egg inside, they also seal up the hole with a gelatinous secretion; this can make it much more difficult to detect infestations before they’ve become obvious and distressing.

Rice Weevil Control Solutions

Fortunately, a rice weevil larva takes about one month to develop. It then takes several more days for the pupated weevil to mature and eat its way out of its food; this gives you some time to take care of these pests if you catch them early, before a population explosion.

  • Find the source: Not many people have large bags of dry rice, or corn laying around, but consider what else in your home could be serving as their food. Dry beans, nuts, birdseed, ornamental corn, dry pasta, and even dry pet food can attract them.
  • Throw out the infested product: Take any bags of flour, dried corn, etc. with weevils and throw them out, along with any dry products that were nearby. For the future, keep all such items in airtight containers.
  • Clean your home: As with any pest, cleaning up will discourage them. In particular, empty and clean any places that you saw them that didn’t contain food, such as dresser drawers.
  • Pre-treat suspected food: If you’re worried that some food might be infested with rice weevils and you want to be especially cautious, you can heat the food to 140 degrees Fahrenheit for 15 minutes, or longer; which will kill all the weevils at any stage, from eggs to adults. Doing this with any new grains that you buy can also help protect you from bringing in new infestations from the grocery store.

Because rice weevils stay near food, only professional pest controllers should be involved in any chemical treatments. Otherwise, there is a risk of chemicals reaching food that wasn’t infested. The experts at Bulwark are ready to hear your situation and will handle any weevils and other insects in a sensible, effective way, guaranteed.

Common Rice Weevil Questions

Do Rice Weevils Only Eat Rice?

No, despite their name, they can eat various dry grains, and also beans, nuts, and even fruit such as grapes, although they prefer dry over fresh. Other species of weevil in the Sitophilus genus have more specific diets, such as only the acorns from oak trees. The tamarind weevil is only known for eating tamarind.

Are Rice Weevils Fragile?

If you give a bag of weevil-infested rice a hard shake, you might mistakenly believe that you’ve killed them all through blunt force; this is not the case. Several weevil species will feign death when disturbed, folding up their legs and not moving, until they decide it’s safe to move again. The only guaranteed way to kill rice weevils without chemical control is to expose them to extreme heat.

Since rice weevils are so small, it might be challenging to know for sure if those are the insects you’re dealing with. Fill out our online home assessment form and describe the problem as best you can. Our team will contact you to diagnose your pests and find the best solution ASAP.

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