Last week at a Master Gardener class in Portage County, the conversation turned from landscape pests to insects inside the home.
One class member described finding a little moth, flying around her living room light. It was a small tan moth with powdery wings that shed scales when swatted with the fly swatter. Later in the week, I talked with an Akron homeowner who had spotted about 10 moths in the last few weeks in various rooms in the house.
I had to share the unpleasant news that both houses probably have infestations of the Indian meal moth. At some point, nearly everyone has problems with this pest, which is commonly brought to the home through infested packaged foods, birdseed or dog food. Contaminated food can bring eggs or caterpillars into the pantry.
As they feed, the caterpillars spin messy silk in their food. The caterpillars then form small cocoons under shelves or in cracks and crevices in the pantry. Adult moths later emerge; females can lay 60 to 300 eggs, which can mature in as little as four weeks, quickly building up the household population.
Unfortunately, a kitchen can maintain an infestation of Indian meal moths without many obvious signs. The caterpillars feed out of sight, and the well-hidden cocoons are small and white, often tucked back into rarely-seen corners of cabinets and pantries. The most obvious sign of the Indian meal moth is the adult flying in a zigzag pattern through the home, resting on walls or attracted to lights.
Adult meal moths may be seen anywhere in the home, not just in the kitchen. An adult meal moth is a more-than-gentle suggestion that some changes are needed in cleaning and food storage.
When my daughter was in middle school, she took an interest in baking, and would scour through her grandmother’s cookbooks for new recipes to try. She was curious why recipes from older cookbooks always called for sifting flour, while few modern recipes do. Traditionally one of the main reasons for sifting flour was to remove insects, insect parts and webbing before baking. Modern milling and storage practices have reduced the occurrence of insects in flour and other foods, but meal moths, book lice, drugstore beetles and other insects still create problems in the kitchen.
Spring is an excellent time to tackle food storage issues, whether meal moths are seen or not. Preventing insect infestations is easier than trying to find the source of infestation and clear up a problem, so consider following these food storage guidelines:
• Inspect products before purchase, taking careful note of expiration dates.
• Avoid all damaged food containers. Inspect plastic and cardboard containers before storage, since meal moth caterpillars can easily chew through this material.
• When purchasing bulk or seldom-used foods, buy only as much as will be used in a few months’ time, and store these products in hard plastic or glass containers. Herbs or spices can be stored in the refrigerator, and other seldom-used foods can be stored in the freezer.
• Make a habit of storing flour, oats, barley and other grains in hard plastic or glass containers with tight-fitting lids, particularly if these foods are seldom used.
• Establish a regular cycle of cleaning to prevent pantry items from harboring pests. Items not used in six months should be eaten, frozen or thrown out.
• Food suspected of infestation can be put into the freezer (0 degrees) for four to seven days. Freezing temperatures will kill all meal moth life stages. After freezing, foods can then be stored in hard plastic or glass until used, although sifting may be necessary.
• Store birdseed in a container with a tight-sealing lid, in the garage (not the house) if possible.
• Pet food should also be stored in hard plastic containers with tight-sealing lids.
• Careful and regular cleaning of all food storage areas is essential. Meal moths can survive on very little food, including crumbs or small amounts of spilled flour or cereal. Clean all shelves, top to bottom, with hot soapy water. Pay careful attention to cracks and crevices, where cocoons are likely to hide.
• Decorative items in the home, such as wreaths or flower arrangements with decorative wheat or corn, can be an important and often overlooked source of infestation. Periodically deep freeze these items, or limit their use indoors to a few months before cycling them to outdoor areas or composting them.
Denise Ellsworth directs the honeybee and native pollinator education program for the Ohio State University. If you have questions about caring for your garden, contact her at 330-263-3700 or click on the Ask Denise link on her blog at www.osugarden.com.