University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Indian Meal Moths Are
Unwelcome Holiday Visitors

December 18, 1997

Hopefully an unwelcome visitor will not be showing up around your home this winter. Indianmeal moths, a pest of cereals and grains, are a common indoor pest that seems most noticeable in late fall and winter. Just in time for the holidays is my annual column on this insect.

Adult moths are very small (about 3/8 inch long with a 3/4 inch wingspan) and brownish-gray, with a two-tone appearance to their wings. Adults do not feed, but lay eggs in or near dried food. From these eggs emerge small whitish larva with dark heads. Larva will spin silken webs over the surface of the infested food source.

Rice, oatmeal, cornmeal, pasta, cake mixes, granola, walnuts, pecans, and dates are among the food products infested by this insect. Two sources often overlooked are birdseed and dry dog food. Indianmeal moths frequently are brought in with the birdseed and then spread to the rest of the home.

When full-grown, larva migrate out of the food source and often across walls and ceilings, making cocoons in cracks and crevices, emerging a few days later as adult moths. The complete life cycle from egg to adult moth takes one to two months.

Proper food storage and sanitation is the key to dealing with this pest. Thoroughly inspect all open and unopened dried food packages from the cabinets. Discard anything showing signs of insects. Next, vacuum shelves and cracks/crevices in the cabinets and storage area. Dispose of vacuumed material. Spraying a household pest insecticide into cracks and crevices may be done, but is not absolutely essential to control this pest.

Placing stored food into insect-proof containers, such as glass jars and plastic canisters with air-tight seals, is a key to managing this insect and other similar pests. As a general practice, dried food products to be stored more than six weeks should be transferred into insect-proof containers, whether open or not. Avoid purchasing crushed or damaged packages of cereal or grain products. Store birdseed in air-tight containers or in the garage.

Even after going through all of these procedures, you may still see more moths around. But as long as they cannot get back into food sources, the problem should be solved.


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