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, grain
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
Granary Weevil
Pea/Bean Weevil
Angoumois Grain Moth
Whole kernels of oats, wheat, rice, barley, ans peas, beans, and bird seed

 

Scavengers: Feed only on grain after the seed coat has been broken either by milling or by some other insect.

Pest Usually Feeds On
Sawtoothed Grain Beetle
Red Flour Beetle
Confused Flour Beetle
Cereals, cornmeal, flour, macaroni, oats, dry pet food, “shake and bake” coating mixes, spices, etc.
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.