Pantry Pests
You can certainly lose your appetite fast when you find little worms or tiny
bugs in the flour. The incidence of "cereal or pantry pests" has greatly
increased in the last five years. This fact sheet will help you control and
prevent these scavengers from infesting your food and your home.
Where do they come from?
Pantry pests may fly into your house from the outside or more likely they are
brought in on grain based products, pet food, and bird seed purchased at
grocery, natural food, or feed stores.
What is their growth and development
All of the pantry pests have four life stages: egg, larva, pupa, and adult. They prefer warm and humid
conditions. They cannot live very long at very low temperatures or very high temperatures. The larva and
adult stages may be noticeable in food products.
What kind of products do they infest?
These pests infest flour, dry pet food, peas, dried vegetables, grain, milled cereal, bran, nuts,
macaroni, spaghetti, spices, dried flowers, etc.
What are the common pests?
There are four groups of common pantry pests. They are classified as follows:
- External Feeders: feed from the outside of the grain
| Pest |
Usually Feeds On |
| Drugstore Beetle & Cigarette Beetle |
cereals, dry dog food, spices, powdered milk, rice, seeds, grains |
| Indian Meal Moth (larva & adult) |
Stored grains, milled cereals, corn meal, dried fruits, bird seed, nuts, dried flowers |
- Internal Feeders: larva feed entirely within the kernel of the whole grain
| Pest |
Usually Feeds On |
| Rice Weevil |
Whole kernels of oats, wheat, rice, barley, ans peas, beans, and bird seed |
| Granary Weevil |
| Pea/Bean Weevil |
| Angoumois Grain Moth |
- Scavengers: Feed only on grain afer the seed coat has been broken either by
milling or by some other insect.
| Pest |
Usually Feeds On |
| Sawtoothed Grain Beetle |
Cereals, cornmeal, flour, macaroni, oats, dry pet food, "shake and bake" coating mixes, spices, etc. |
| Red Flour Beetle |
| Confused Flour Beetle |
| Mediterranean Flour Moth |
Flour, nuts, chocolate, beans, dried fruit |
- Secondary Feeders: Feed on material that are damp and have mold growth present
| Pest |
Usually Feeds On |
| Mealworms |
Damp and moldy boxes of cake mixes, animal feed, cereals, etc. |
How do I get rid of them?
- Locate the source of infestation. Look for boxes or bags of grain, pasta, coating mix, flour, spices,
bird seed, dry pet food, etc. If any of the products appear infested, dispose of the product and the
container into a plastic garbage bag and remove it from your house. If you wish to salvage the product
you may do the following:
- Heat the infested grain in an oven at 130º F for 1/2 hour.
- Place the grain or infested product in a freezer at 0º F for 4 days.
- Microwave on high setting for five (5) minutes.
- Clean and remove food particles. Thoroughly vacuum the cupboards to remove loose food, insects,
larva, cucoons, webbing, etc. Check all of these areas:
Food storage shelves Under cans and boxes Unwashed flour sifter
Under refrigerator and stove Between corners of shelves Between stove and wall
Bags of pet food or bird seed Under sink Dried flower displays
Corner or edge of wall and ceiling Behind pictures or clocks on the wall On or around spice racks
- Insecticide treatment.
- For crawling insects: apply a residual insecticide into the cracks and crevices and around the edges
and corners of the shelves in the cupboards. Do not spray the entire surface of the shelf. Treat other
edges and corners in rooms where the insects were found. After the surfaces have dried, wipe the
cupboards with a damp cloth and replace the foodstuffs, dishes, utensils, etc.
- For flying moths: The adult moths may be swatted from the air or killed with a properly labeled
aerosol (usually containing pyrethrins). Read and follow the label directions on the container.
- Use pheromone traps. The adult moths and beetles can be attracted by pheromones and captured in
sticky traps. Be sure to purchase pheromone traps specific to the pest you have. The pheromone traps
should be placed or hung in areas where infestation is suspected. One or more traps may be needed
depending upon the number of rooms and the individual circumstances. For additional instructions, read
and follow the directions on the label of the pheromone traps. Remember, the trap alone is a
"monitoring tool" not a control method.
How do I prevent a reinfestation?
- When purchasing grain products, examine the package for damage or tears and look for the
expiration date to ensure freshness.
- Do not overbuy and overstock grain products such as rice, pasta, noodles, pet food, bird seed, etc.
- Store grains you plan to keep for a long time in the refrigerator or freezer.
- Transfer broken packages to containers with tight fitting lids.
- Inspect bags of dry pet food and bird seed for signs of infestation. Do not keep bird seed or other
whole grain products in your basement or attached garage for any length of time.
- Always use older packages first.
- Keep storage areas dry and well ventilated to discourage moisture loving pests.
What if I keep seeing the adult moths?
The adult moths may persist for a week or two after the treatment. This results when larva have crawled
into inaccessible areas and begin to hatch out. If the appearance of the adult moths persist beyond two
weeks, there may be some other undiscovered source of infestation. Continue the search. Pheromone
traps may help identify the source of the problem and will continue to capture the adult moths.