The Homeowners Column

The Homeowners Column

Indianmeal Moths in Stored Food

November 10, 2004

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

One evening you're snuggled up on the couch doing your best cocoon impersonation. You notice there is something in the room moving much faster than you. It's those annoying small brown moths flying around the television. You know, those moths that just turn to powder when you squish them. Indianmeal moths have come for a visit.

A variety of beetles and moth larvae can be found in stored grain products, nuts, dried fruit and spices. Some pantry pests can bore through commercial wrappers or containers. Some may enter homes in infested food or its packaging. An adult female can lay more than a hundred eggs, so it doesn't take long to get large infestations that destroy large quantities of food.

A food label on a caterpillar might be a nutritionist's dream - high in protein and low in fat. Although in our culture insects are rarely listed on menus, many cultures rely on insects in their diet. The concern in stored food are the microbes and fungi that may come in with the insects which may not be killed by cooking the product. People are strongly urged to destroy products infested with pantry pests.

Indianmeal moths are 3/8 inch grayish brown moths which infest food as caterpillars, also called larvae. The larvae are white and spin silken threads throughout and over the surface of the food. When full-grown, larvae migrate out of the food source often across walls and ceilings to make silken cocoons in cracks and crevices. I even found one on the back side of a picture frame. A few days later adult moths emerge from the cocoons. The complete life cycle from egg to adult moth takes one to two months.

Indianmeal moth larvae are general feeders on dried fruit, crackers, nuts, powdered milk, cake mixes, candies, pasta, bird seed and dried pet food. One homeowner found some in the bathroom infesting a bath treatment that contained oatmeal. Larvae will even feed on the kid's seed craft project. Adult Indian meal moths do not feed. These are not the same moths that attack clothing.

To prevent infestation by pantry pests:

  • Inspect food for possible infestation when it's first brought home.
  • Freezing grain products for 3 days after purchase is a good habit.
  • Grain products should be stored in air-tight containers, pressure-sealed jars with rubber gaskets or in the freezer. If possible, remove the original cardboard package.
  • Dry pet food and bird seed should be stored in heavy plastic containers with tight sealing lids. Don't store grain products over a year old.
  • Cupboards and shelves should fit flush with walls or be movable to provide easy cleaning.

If pantry moths or beetles are seen:

  • Pull everything out of cupboards where grain products are kept. Thoroughly examine all opened and unopened products with a grain base such as spaghetti, cake and biscuit mixes. Also check all spices especially chili powder, paprika and red pepper.
  • Discard infested packages.
  • Thoroughly clean cabinets by vacuuming cracks and using hot soapy water on shelves.
  • Many pests can live and breed in spilled foods. Spills should be cleaned promptly.
  • Freezing infested food not meant for human consumption will kill most common pantry pests. Freeze products for 3 days then bring out to room temperature for 3 days then back into the freezer for 3 days.

No chemical controls are recommended or are as effective as prevention and sanitation. There are sticky traps available to capture the adult moths.

Several small beetles may also infest stored food but the control measures are the same.

Even after going through all of these procedures, you may still see a few moths flying. However as long as food is stored properly it should mean the end of your unwelcome guests.

http://www.urbanext.uiuc.edu/bugreview/pantrypests.html

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