Indian Meal Moths

So… You opened the cupboard, and a little moth flew out.  Nothing to worry about.  It’s “just a moth.”  

Over the next few days, you see a few more, but after a while, you see them daily, and they seem to be getting into more rooms...

You may have tried spraying them with something you picked up at the store, but they keep coming back.

The next time you see one of these moths, look closer.  If it’s sporting a gray and copper, two-tone paint job, you likely have an Indian meal moth infestation.  

This moth is frequently a pest of stored food and can cost you a small fortune in dry goods if you don’t act quickly to find the source of the infestation.

The adult moth ranges in length from between 1/4 and 3/8 inch and is easily identified by its distinctive markings on its wings  (shown above).

Damage:

Damage to food is caused by the caterpillars of this moth.  They prefer to feed on coarse grains and meals (corn meal, grits) but have been found in dried fruit, nuts, bird seed, dry pet food, cereal, chocolate, and dried red peppers.

Caterpillars damage food by consuming it, degrading it with their droppings, and most notably by contaminating it with the silk webbing they use to create a protective mat.  This silk is often the first noticeable sign of infestation.

In advanced stages of infestation, these tiny, cream-colored caterpillars will be seen crawling away from infested foods to weave their cocoons.  They tend to crawl up and away from where they grew up, and their silken cocoons can usually be found in the cracks and corners of shelving immediately above the infested food.              

Indian meal moths don’t transmit any known diseases, but the damaged food becomes highly unpalatable.

Origin:

It is impossible to destroy 100% of the insects’ eggs unless the product is cooked during processing, so often, eggs are in products when we buy them.  

Many products brought into our homes, like corn meal, grits, and quinoa, escape this kind of processing or get re-exposed to infestation during storage and transport.  Bird food and pet food are two of the more common items that become reinfested during storage and transport.  

Most infestations are encountered in products that have been improperly stored or kept beyond their usable shelf life, allowing the eggs to hatch.  

Procedure:

Once you discover an Indian meal moth in your home, it is necessary to inspect all of your stored food (unless refrigerated) for evidence of caterpillars, webbing, and cocoons.  This includes pet food, dog bones, bird seeds, and bulk grains.

Canned goods, fresh fruit, and vegetables are immune to infestation.  As are sealed plastic packages, “zip-loc” bags, Mason jars, and Tupperware unless the moths originated there.  Inspect the lids for cocoons before returning them to the cupboard.  Boxed goods and twist-tie bags are especially vulnerable.

Infested food must be disposed of outside of your home.  Any food kept must be stored in air-tight containers to prevent re-infestation and isolate any infested food that wasn’t discovered.

Storage shelves should be washed thoroughly, and a residual pesticide should be applied to cracks and crevices around shelves and cupboards.

The general rule for preventing most food pests is any dry goods that will be stored for 30 days or more must be kept in air-tight containers or refrigerated.  This includes pet food and bird seed.add t

If products are to be stored longer than 3 months, they should be frozen.