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Insects in Stored Food

Many species
Updated Dec 19, 2023
 
1

Make a Positive Identification

There are several species of insects that infest stored food. Control methods are the same for all of them.

Meal Moth
Species: Meal Moth
Adult meal moth

Meal moths (Plodia interpunctella) commonly infest a wide variety of stored foods. Adult meal moths are 1/3 to 2/5 inches long with a wingspan of about 3/5 of an inch. Their wings are held flat along the length of the body as shown in the photo. The front third of their wings is whitish-gray. The rest is coppery brown.

Species: Meal Moth
Meal moth larvae

Meal moth larvae feed on and damage stored foods such as grains. They are about 1/2-inch long when fully grown. Their color is white or sometimes pinkish or greenish. Meal moth larvae have three pairs of legs close to the head, as shown in the photo. They also have leg-like structures farther down the abdomen.

Species: Meal Moth
Webbing in a container, with larvae and adult moths

Mohammed El Damir, Bugwood.org

Meal moth larvae create a web as they grow and crawl around. The photo shows Indian food infested with meal-moth eggs, larvae, webbing, and adults.

Beetles
Species: Flour Beetle
Adult red flour beetle

Peggy Greb, USDA Agricultural Research Service, Bugwood.org

Confused flour beetle (Tribolium confusum) and red flour beetle (Tribolium castaneum) are similar species. Adult beetles have shiny, flattened, reddish-brown bodies. They are about 1/7-inch long. Adult beetles of these species damage stored food.

Species: Flour Beetle
Flour beetle larvae

© Ken Gray Insect Image Collection

Small larvae are slender, cylindrical, and wiry in appearance. They are about 3/16-inch long and white, tinged with yellow. In general, beetle larvae are either legless or have three pairs of legs close to the head as shown in the photo. Beetle larvae damage stored food.

Species: Cigarette Beetle
Cigarette beetles

Brian Little, The University of Georgia, Bugwood.org

Cigarette beetles (Lasioderma serricorne) and drugstore beetles (Stegobium paniceum) are similar species. Adult beetles are 1/8-inch long, oval-shaped, and light brown. Larvae and adults of both species damage stored food.

Other Insects in Stored Food
Species: Angoumois Grain Moth
Gray moth on corn

Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Angoumois grain moth (Sitotroga cerealella) is another pest in stored whole grains such as rice, wheat berries, and corn. The moths bore into intact seeds and feed inside the seed covering.

Species: Mediterranean Flour Moth
Moth with gray, mottled wings

© Ken Gray Insect Image Collection

Mediterranean flour moth (Anagasta kuehniella) prefers to feed on flour meal and whole cereal grains.

Species: Bean Weevil
Bean weevils with damaged beans

LiuSol, iStock

Bean weevils (Acanthoscelides obtectus and Bruchus pisorum) damage bean crops in the field. They also feed on and damage stored beans.

Species: Grain Mite
Grain mites

© Ken Gray Insect Image Collection

Tiny mites also infest stored food. They occur in moist or damp conditions. Watch for piles of brownish dust on shelving, around flour sacks, or on the surface of stored foods.

Species: Carpet & Hide Beetles
Carpet beetle larvae
Varied carpet beetle on leaf
Photo credits
Left:

Gary Alpert, Harvard University, Bugwood.org

Right:

Whitney Cranshaw, Colorado State University, Bugwood.org

Carpet beetle larvae are covered with tufts of hair as shown in the photo (left). These larvae damage many stored foods.

Carpet beetles and hide beetles are similar species. Both are about 1/10-inch long. Carpet beetles are mottled white, brown, and dark yellow as shown in the photo (right). Hide beetles are brown.

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2

Insects in Stored Food Benefits

  • Insects in stored food are regarded as pests. They don’t have any benefit for people or the environment.
 

Insects in Stored Food Risks

  • Insects in stored food are not known to spread any known diseases, parasites, or pathogens.
  • They can contaminate stored food with hairs, droppings, webbing, and secretions.
  • Hairs from some beetles can irritate your mouth, throat, and stomach when ingested.
  • Insects in food spread microbes that rot food, especially in warm, humid conditions.
Risk Card
Does it cause harm?
Adults & Children
Low
Property
Some
Pets
None
Annoyance
Some
Environment
None
Action Recommended
 
3

Take Action

Take action for insects in stored food. The sooner you take action, the easier the problem will be to address.

Do I need to take action?
Yes. They ruin stored food.

What if I do nothing?
Pantry pests won’t go away on their own. They will ruin more stored food if you don’t take action.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon  and other states  can suggest other methods.

 
4
Solutions for Insects in Stored Food
  • If you find small moths flying or beetles crawling around your kitchen, look for infested stored food. Remove the infested food.
  • By the time you notice the insects, they have likely spread to multiple food packages.
  • Discard infested foods and clean the area thoroughly.
  • Use pheromone traps to catch and monitor for insect activity.

Jump To

Method Does it work? Is it safe? Recommendation
A
Clean Up Insect Messes
Very effective
Low risk
B
Pheromone Traps
Effective
Low risk
C
Insecticides for Indoor Use
Does not work
High risk
D
If Using Insecticides, Protect Yourself & Minimize Risks
E
Prevent Insects in Stored Foods
 
A

Clean Up Insect Messes

Non-Chemical Method

Signe Danler, Oregon State University

Clean Up Insect Messes

Cleaning up pest infestations in the pantry is a required step to get rid of the problem.

Does it work?
Very effective
How much effort?
Moderate effort
What's the risk?
Low risk
Possible risk of exposure or harm from chemicals
NONE
Cardboard, paper, and plastic food packaging

Signe Danler, Oregon State University

Inspect food stored in cardboard, paper, and plastic packages. Look for tiny holes in food packaging, even unopened packages.

Flashlight used to inspect cabinet crevices

Weston Miller, Oregon State University

Use a flashlight to look for webs, pupae, larvae, moths, or beetles in your food storage area. Look for webbing and debris in cabinet crevices.

Mixed grains spread on cookie sheet

Signe Danler, Oregon State University

Pour the package contents onto a cookie sheet. Inspect stored food more thoroughly.

Sealed bag being dropped in trash can

Signe Danler, Oregon State University

Discard any food with signs of insect infestation. Seal it in a plastic bag. Discard it in the trash or landfill.

Vacuum with crevice attachment

Signe Danler, Oregon State University

Clean cabinets thoroughly. Vacuum corners and crevices with a crevice attachment as shown in the photo. Wipe down surfaces with soapy water.

Stored food products infested by insects should be considered ruined and thrown away. However, if the infestation is minor, the food can be safely salvaged. Sift the insects out. Cook the food for at least ½ hour at 140℉ or higher. The heat will kill insect eggs, larvae, and adults. Freezing insect-infested food for at least 3–4 days will also kill insects. Eating insect-infested food that’s been cooked or frozen isn’t known to cause illness or harm.
 
B

Pheromone Traps

Non-Chemical Method

Weston Miller, Oregon State University

Pheromone Traps

Use pheromone traps to monitor and trap meal moths and food pantry beetles.

Does it work?
Effective
How much effort?
Low effort
What's the risk?
Low risk

Pheromone traps use natural scents to attract insects and sticky glue to capture them. They don’t include pesticide ingredients.

Possible risk of exposure or harm from chemicals
NONE
Package of pantry pest pheromone trap

Weston Miller, Oregon State University

The white box on the example product highlights “ATTRACTS & TRAPS MOTHS & OTHER PESTS.” Traps often attract several different pantry pest species.

Indian meal moths caught in pheromone trap

Whitney Cranshaw, Colorado State University, Bugwood.org

Pheromone traps attract insects with natural scents. They catch insects on a sticky surface. Check them weekly.

More About Pheromone Traps

  • Pantry pests can live for many weeks without food. Use pheromone traps to detect pests that may still be present after you clean up infested food.
  • Place the traps near a previous infestation. Check the traps weekly. Most traps remain effective for about three months.
  • If you find moths or beetles in traps, inspect food packages again for an infestation. Dispose of infested food and clean up the mess as needed.
 
C

Insecticides for Indoor Use

Chemical Method: Use with caution

Weston Miller, Oregon State University

Insecticides for Indoor Use

Insecticides (insect killers) are not recommended for controlling insects in food.

Does it work?
Does not work

They don’t kill insects inside food packages. Food packaging protects the insects from contact with insecticides.

How much effort?
Moderate effort
What's the risk?
High risk

Spraying pesticides on or near food can contaminate your food and cause harm to you and your family.

Possible risk of exposure or harm from chemicals
Using insecticides includes some amount of risk. The lowest risk comes with using alternative methods.

You may be exposed to an insecticide if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Touch or eat plants that are wet with spray (you, pets, or children)
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.

If you’ve already applied an insecticide for food pantry pests:

  • Throw away any food that has come in contact with insecticides.
  • Thoroughly wash cupboards, containers, and dishes that have come in contact with insecticides.
 

If Using Insecticides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution

The Label is the Law

ALWAYS read the label before using insecticide products. The label is a legal document that provides information on how to safely use the insecticide. This helps avoid harm to human health and the environment. Using an insecticide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

  • Labels are different for every product and they often change over time.
  • Use a magnifying glass.
  • Pay attention to CAUTION, WARNING, and DANGER statements.
  • Pay attention to the PRECAUTIONARY STATEMENTS.
  • The law states you must read and follow insecticide instructions.

Protect Yourself
Eye, skin & lung irritants

  • Wear gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
  • Avoid contact with eyes, skin, or clothing.
  • Wash hands after mixing or applying, and before eating or smoking.

Protect Children & Pets
Keep out of the reach of children.

  • Keep children and pets away from the application area.
  • Remove toys and pet dishes from the area before applying insecticides. Wait until spray has dried or dust has settled.

Storage & Disposal

  • Store out of the reach of children and pets.
  • Store in a cool and dry place.
  • Never pour down any drain.
  • If you mix too much, apply it rather than storing it.
  • Don’t put pesticide containers in the trash unless instructed by the label.
  • Take unused insecticides to a hazardous waste facility.

Call  1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call  503-234-3000, email   or visit Metro’s website  

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management  (Oregon Department of Agriculture).

NEED HELP?

The National Pesticide Information Center (NPIC)  can answer questions about pest control chemicals.
 1-800-858-7378 or npic@ace.orst.edu  

Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.

Your local Extension Specialist in Oregon  and other states  can suggest other methods.

 

Prevent Insects in Stored Foods

Torn bag of flour

Signe Danler, Oregon State University

Inspect Food Packages
  • Inspect packages or bulk products before buying. Don’t buy broken or damaged packages of food. They are more likely to become infested.
  • Check the freshness packaging date.
  • When buying large quantities of whole grains or beans, freeze them for at least four days to kill any eggs or insects that may be present.
Sealed, sturdy food storage containers

Signe Danler, Oregon State University

Follow These Storage Tips
  • Store food that attracts pantry pests in glass, metal, or heavy plastic containers with tight-fitting lids. Don’t store food items in plastic or paper bags, or cardboard boxes.
  • Don’t store large quantities of bulk foods for longer than 2 months unless they are kept in the freezer.
  • Store seldom-used grains and spices in a freezer.
  • Don’t mix old and new food together. If the old food is infested, the pest will invade the new food. Use the oldest foods first.
Food storage cupbard

Photographer, iStock

Clean Food-Storage Areas Regularly
  • Clean shelves, bins, and other food-storage areas regularly.
  • Clean up spills and crumbs in food-storage areas. Spilled food attracts insect pests.
  • Vacuum cracks and crevices to get rid of eggs, pupae, and spilled grains.
  • Clean the surfaces of food-storage areas with hot soapy water. Let the area dry before replacing items.
  • Wash old containers before filling them with new food.
  • Check and clean areas where pet food and birdseed are stored.
  • Cleaning up stored food messes also minimizes food sources for mice and rats.
Pheromone trap with moths

Whitney Cranshaw, Colorado State University, Bugwood.org

Monitor with Pheromone Traps
  • Watch for small moths or beetles crawling or flying around your kitchen. Look for the food source of these pests and remove it immediately.
  • Use pheromone traps (see section 4) to monitor for the presence of pantry pests.
  • If you see pests more than 3 weeks after an infestation was cleaned up, there is still an infested food source.
  • Pantry pests can breed in rodent baits. Be sure to check frequently and discard infested baits.

Content provided by writer Signe Danler. Pesticide safety information edited by Kaci Buhl.

 Reviewed by OSU Department of Horticulture.

Photo of Weston Miller

Weston Miller

Project Founder and Content Writer

Weston Miller served as Community and Urban Horticulture faculty for Oregon State University Extension Service for Clackamas, Multnomah, and Washington Counties. Weston is an author for content for this website. He developed funding partnerships with Portland area agencies to initiate and build out the Solve Pest Problems website focused on this goals:

Signe Danler

Signe Danler (Editor/Writer)

Signe supports the OSU Extension Master Gardener Program by producing educational content for online Master Gardener training courses, and teaching and managing the OSU-Extension online Home Horticulture courses. She also designs residential and commercial landscapes, specializing in regenerative gardening and landscaping practices.

Photo of Kaci Buhl

Kaci Buhl

At the state level, I lead the Pesticide Safety Education Program (PSEP). The program hosts live recertification events around the state, serving over 1,000 licensed pesticide applicators each year. We also produce web-based training modules and license-preparation study manuals. Special training for unlicensed pesticide applicators is also available through a grant from the USDA Specialty Crop Block Grant Program. The PSEP at OSU works closely with the Oregon Department of Agriculture's Pesticides Division.