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Michigan State University Extension
Home Maintenance And Repair - 01500522
06/24/03

Meal Moths



The most observable life stage of the Indian moth is the adult. It can be observed flying around the inside of the house or apartment. The moth is small with a wingspan is of 1/2". The coloration of the moth is very distinct. The wings are dull gray in background with the wing tips a copperish reddish brown. When the moth is resting, the wings are held tightly to the body. When observed flying in the household the Indian meal moth is often mistaken for a clothes moth. Clothes moths are smaller (1/4" wingspan), dull gray with no distinctive markings.

The Indian meal moth caterpillar is about a half inch long when fully grown and is dirty white, sometimes with greenish and pinkish hues.

The larvae (caterpillars) cause all of the damage. They are general feeders and commonly infest grains and cereals, grain and cereal products, cornmeal (Indian meal), graham flour, dried fruits, nuts, chocolate, cookies and dried pet foods and animal feeds. Less commonly, they may also be found in powdered milk, candies, beans and peas, ground chili pepper, garlic, dried meat, dried mushrooms, garden seeds and beehive products.

Damage to stored food by the caterpillars greatly exceeds the amount of food actually eaten because the larvae spin large amounts of silk as they travel and feed. This webbing is often dense enough to attract attention when stored products become heavily infested, and makes the food worthless. Mature larvae usually leave their food when it is time to look for pupation sites. As a result they are often seen climbing up walls and cupboards. An infestation can also be suspected when the adults are seen flying to lights in the kitchen and other rooms of the house. The moths are very active during the evening and night-time hours; they are commonly attracted to television screens at night.

A second meal moth sometimes found in the home is the Mediterranean flour moth. This moth appears similar in body shape to the Indian meal moth, but the wings are leaden gray with wavy black markings (definitely not bi-colored). The Mediterranean flour moth has a characteristic pose when resting: the front of the body is raised, giving the wings a distinct downward slope, with the tip of the abdomen protruding up between them.The habits and biology of this species are similar to those of the Indian meal moth. This species prefers flour and meal, but also infests grain, bran, cereal products and other foodstuffs.

The common meal moth, is the third species which may be found in houses. It is the largest of the three species, having a wingspread of about 1 inch. The body is brownish an the wings are light brown with dark brown patches at both the base and tip, with two distinct, white, wavy lines separating the two shades of brown. The larvae (caterpillars) of this species prefer cereals, cereal and grain products, hay and many types of dried vegetable matter, especially if the foodstuffs are damp or subject to high humidity. The larvae are also large, about an inch, and they have distinctive black heads.

Integrated Indian Meal Moth Management
Purchase susceptible foodstuffs in quantities that can be used in a short time: less than 2-4 months, if possible. When purchasing packaged food, be certain the containers are not broken or unsealed. Check the package for a freshness date. Once food is in the home, use older packages before newer ones, and opened ones before unopened ones. Storing dried foods in a freezer will prevent pest development. Keep food storage and preparation areas clean at all times; spilled and exposed food attracts insects.

Once an infestation of meal moths is suspected, prompt action is important in preventing losses of large quantities of stored food products. The following steps will be useful in bringing an infestation under control.

(1) Carefully examine all susceptible foods and other stored products that may have been exposed to the infestation. This includes all pet foods and seeds. Do not overlook unopened paper and cellophane wrapped products, as the insects may even be found in these. You will probably want to throw away all infested products. While Indian meal moths can be killed by heating (140 degrees F for 1 hour) and Mediterranean flour moths can be killed with cold (0 degrees F for 2 days), there is no easy way to separate the insects from the food products.

(2) Contents from all packages (opened or unopened) which appear to be uninfested should be transferred to glass or plastic containers with tight-fitting lids. It is possible that eggs were laid in these products and that they may hatch later and lead to an infestation if not contained. Glass containers make periodic examination of the food easier.

(3) Remove all food, food containers and utensils from the infested areas and clean thoroughly, first with a vacuum cleaner and then with soap and water. Special attention should be paid to cracks, crevices and corners (including under and behind appliances) were bits of flour, meal or other food may have accumulated.

(4) We do not recommend using an insecticide. For a complete listing of suggested control options for all home, yard and garden insect pests see: Michigan Insect Pest Management Guide, 1991.

These kinds of publications are available from your local Cooperative Extension Service. Read and follow instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health.

References

Revised by Tom Ellis, M.S., Department of Entomology

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MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

This information.was reviewed as of June 2008.  For more information about the contents please contact costner@msu.edu for webpage problems strausc@msu.edu .