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The Indian meal moth goes by many names, including grain moth, flour moth and, most ominously, the “pantry moth”.

As the aliases imply, this common insect infests food supplies. If you have Indian meal moths in your pantry, you are sharing an unpleasant experience with generations of farmers and food processors.

Indian meal moths are native to Europe, but have spread around the world. They aren’t picky eaters and adapt to different climates. In short, they travel well and are tough to eradicate.

A pioneering entomologist, Asa Fitch, gave the Indian meal moth its American name in 1856 because the insect was commonly found in maize meal.

Fitch identified the bug in his, “Reports of the Noxious, Beneficial and Other Insects of the State of New York.” Unfortunately, the Indian meal moth has been more noxious than beneficial.

As a flying adult, the moth doesn’t eat, but when still a caterpillar, it eats practically anything. The U.S. Department of Agriculture published a paper in 1931 detailing the Indian meal moth’s diet in California. The moth was known to feed on grain, fruits, nuts, vegetables, graham crackers, dandelion roots, chocolate marshmallows, and each other.

“Several instances of cannibalism have been observed,” the report noted.

Caterpillars were put in a jar containing raisins, dates, dried peaches, apricots, and figs. The bugs crawled over everything, though, for some reason, “the raisins were somewhat less attacked.”

The report also identified the big problem with Indian meal moths: It isn’t so much what they eat, it’s what they leave behind.

“Fruit infested by this species not only contains living worms, but it is increasingly polluted by excrement, cast skins, webbing, dead individuals, and often the cocoons of parasites,” the report stated.

Over the following decades, researchers sought ways to protect food from the Indian meal moth.

In the 1980s, researchers zapped almonds, walnuts, and raisins with low doses of gamma radiation. According to a 1989 USDA report, the radiation killed the caterpillars and even “improved the overall appearance of the product.”

The problem was that the radiation killed the caterpillars too slowly. Food products might still have live worms. Researchers warned about “consumer reaction.”

Two University of Florida researchers in 1998 compiled ways to eradicate Indian meal moths. The ways included freezing infested food at zero degrees for four days or heating it to 150 degrees for 24 hours.

The researchers also advised: “All stored food products brought home from the grocery store should be examined for the tell-tale ‘white worms’ and ‘webbings’.”

We would be interested in meeting the person who inspected their groceries for white worms. We would not, however, be interested in living with that person.

The October 2012 issue of the USDA’s “AgResearch Magazine” reported an effective way to exterminate Indian meal moths — turn loose the wasps!

A type of wasp with the intimidating name Habroban hebetor had proven to be hell on Indian meal moths. The wasp stings the caterpillar. The wasp lays eggs on the paralyzed but alive caterpillar. The eggs hatch and, as the USDA put it, “sucks out their host’s juices.”

If extreme temperatures, obsessive food inspections, radiation, or wasps do not sound like practical solutions to Indian meal moths in your pantry, there is another option.

Several types of chemicals are effective against Indian meal moths. But they have to be applied in the right places, at the right times, and in the right doses. Indian meal moths have five pairs of legs. They travel surprising distances, making tracing the source of an infestation difficult. Also, Indian meal moths over the decades have built up resistance to certain chemicals. It’s important to know which ones will work.

For help exterminating Indian meal moths or other pests in the Portland Metro Area and Southwest Washington, please contact us at, or call us at (503) 284-6269.