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New Mexico State University

New Mexico State University

News Center

Spring Clean to Eliminate Pantry Pests

LAS CRUCES--Washing blankets, airing drapes and sweeping away dust and cobwebs are part of the usual spring cleaning routine. But this year, homeowners also may want to clean out cabinets and pantries to get rid of bugs.

Stored products like pasta, flour and spices make perfect homes for small insects, said Carol Sutherland, entomologist with New Mexico State University's Cooperative Extension Service. Spring cleaning provides a good opportunity to control some of the most common insects.

"One way to check for insects in food is to run your finger along the inside edge of a flour canister," Sutherland said. "If you pick up something that looks like little dust bunnies or is kind of sticky, you've probably got an infestation."

The sticky webbing holds small particles of food and waste from Indian meal moth larvae, she said. The hairless, ivory caterpillars thrive and develop on a wide variety of common stored food products.

The Indian meal moth is about one-half inch long, with silvery gray and copper colored wings. "It will look sort of like a fighter airplane at rest with its wings swept back over its abdomen," she said.

The adult female lays eggs in the cracks or crevices of the cabinet or in openings in boxes and bags of food. Once they hatch, the caterpillars feed on fine grains of flour or the dust in other foods, completing the life cycle, Sutherland said.

Another sign of insects can show up in grain products such as instant or brown rice, Sutherland said. If slender, dark brown particles float to the top when the rice is added to boiling water, an infestation problem exists.

These particles are probably adult saw-toothed grain beetles, she said. The beetles are dark brown with flat, broad bodies and are often mistaken for weevils. They are the most common beetle-type stored product pests in New Mexico and can be found in almost any dry food product, she said.

"Saw-toothed grain beetles also love spices. They produce slender, linear larvae that are not commonly seen," Sutherland said. "This suggests that maybe we eat some of these things sometimes, and we just don't know it."

To check for these tiny pests, get a piece of white paper, shake out the contents of one spice container and wait to see if anything moves, she said. Sift through the contents. Use a magnifying lens to look for other evidence like beetle parts.

Both the moth and the beetle are well-adapted to New Mexico's dry climate and require no extra water to survive, Sutherland said. They are active year-round and can go through at least five to eight generations each year.

"These insects are real opportunists," Sutherland said. "If undetected or ignored, their populations may increase to the point that they are glaringly obvious."

Saw-toothed grain beetles in particular will wander around on floors, shelves and counter tops, she said. Sometimes they are found in silverware, dishes or in kitchen appliances. Although small, they also can bite.

To eliminate these pests, carefully examine dry products, especially those that are not used very often, she said. Look inside containers for abnormal dust or insect parts, then throw the infested ones away outside the house.

When uncertain whether a product is infested, or to keep it from becoming infested, put it in the freezer to kill possible insects, Sutherland suggested.

"Pests really like cake mixes, flour and foods stored for long periods of time, so limit what you buy," she said. "Think realistically, then only buy what you plan to cook for the next month," she said. Also, mark products with the date of purchase, so the oldest ones are used first.

Finally, clean all parts of the kitchen where stored products are kept. Remove everything from the shelves, then dust thoroughly with a towel or a small brush. Pull out the dust drawers, clean the tracks, then vacuum thoroughly behind the drawers.

"A lot of times, you'll find enough food scraps to provide a breeding ground for stored-product pests or other insects, such as cockroaches," Sutherland said.