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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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.
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