Almost all dry, stored food products for people and pets, such as flour, crackers, pasta, dry dog food, and even birdseed are susceptible to being invaded by a host of different six-legged vermin who can make your life, or at least your cooking, quite unpleasant. These food invaders are commonly called 'pantry pests' by those in the know, and their specialty is rendering food unfit for consumption. Anyone who's encountered them can attest to the fact that it can take a full-fledged war, sometimes a lengthy one, to get rid of them for good.
To get rid of pantry pests and prevent them from coming back, the first step is a thorough and detailed examination of all materials in your house to determine what pests you're dealing with, and how extensive the infestation is. Often there is more than one type of pest doing damage, or different life stages of the same pest. To wage the most successful war, you need to know your opponent and use the most appropriate weaponry. The most prevalent pantry pests fall into one of 3 major categories: beetles, moths, and worms.
Flour and Grain Beetles
If you see small reddish-brown colored beetles around your cereals or other grain products, you can bet that you have an infestation of 'bran bugs', a common name that can refer to any of the several types of beetles. The saw-toothed grain beetle gets its name from the 6 'teeth' located on each side of its throat. It's very tiny, only about 1/10 of an inch long, and is thin, flat, and dark red or brown in color. This type of beetle is commonly found in packaged grains and cereal products, seeds, nuts, dried meats, dried fruits, and candy. It lays its eggs on or near the food, often inside plastic wrappings. The eggs hatch into small buff-colored, worm-like larvae which eat for a few weeks and then pupate for a week before hatching into the adult form of the beetle, which can live in your pantry for 2-3 years.
2 other common beetles are the red flour beetle and the amusingly-named confused flour beetle, both of which are reddish-brown and about 1/7 of an inch long. They feed on grains, cereals, dried peas, beans, some drugs, and even cayenne pepper. Hundreds of them can live and reproduce in a single box or bag of food, and if that box or bag is in a pantry, the adults can migrate throughout everything else in the pantry and infest everything they find attractive. Foods in open containers that are untouched for long periods are particularly susceptible. Because the female beetle deposits sticky eggs that are concealed by the food, it can be easy to miss them before they hatch and come to the surface.
There are dozens of other beetles that can take up residence in your food and make life miserable, including the cigarette beetle, cabinet beetle, larder beetle, and spider beetles. All of them are fond of infesting grain products or dried foods, and some have particular interesting proclivities. For example, the drugstore beetle has an extremely varied diet that can include even inedible items such as cosmetics, drugs, and even strychnine. Drugstore beetles have been known to bore through a whole shelf of books, or chew through rolls of aluminum foil or sheets of lead! Some species of beetle pests can produce up to 5 generations in just one year, so a severe infestation can develop in just a few months if you don't try to prevent it.
Worms and the Moths They Turn Into
Most people who see tiny worms in their flour or cereal call them 'mealworms'. That term can be applied to a whole host of pantry pests, all of which are associated with grain products, usually ones that are damp, not regularly used, and stored in undisturbed out-of-the way places such as basements. The yellow mealworm is one of the largest insects that infest cereal products with its adult form being a black beetle about ½" long. Full-grown yellow mealworm larvae are about an inch long, tubular, and rather hard-shelled. It generally takes about a year for the worms to develop into adult beetles. Dark mealworms are very similar except for their color. Both species are often reared by the hundreds in pet foods kept in pet stores. And when you bring an infested bag home for your pet, you may have unknowingly infested the rest of your pantry as well.
Flour moths are among the most common of all pantry pests. Adults have a wingspan of about ¾ inch, and they are often seen flying around the infested area. The larvae damage stored food products and take about 7 weeks to develop into adult moths. The Indianmeal moth is the king of flour moths, being strikingly marked by coppery-colored wings that are about ½ inch long. The larvae are beige or pinkish, and they form webs across the surface of infested material. Its slightly smaller cousin, the Angoumois grain moth, is often confused with moths that attack clothing. Their favorite diet is popcorn, and they develop into their adult stage in 5 weeks or less.
How to Control Pantry Pests
The only way to completely eliminate and control pantry pest infestations is to follow a systematic, complete control program and maintain a good prevention program afterward. Taking any shortcuts or eliminating any steps may result in total failure and a re-infestation.
Carefully examine all susceptible foods. Look for signs of infestation, such as webs, dead beetles, pupae, living beetles, or larvae. Throw away any foods that are heavily infested, or that have signs of previous infestations.
To keep infested food, heat it or chill it. If the food that's been infested is valuable to you and you want to keep it, you can either heat the food at 130 °F for at least 30 minutes, or you can place it in a deep freezer at 32 °F for at least 4 days.
Clean up. Empty all shelves and vacuum the entire area, paying close attention to the edges and corners of cabinets. Wash the shelves and cabinets with warm soap and water.
Spray shelves lightly with insecticide. Particularly in the cracks where the shelves and the wall come together, spray an insecticide labeled for use in kitchen cabinets. If a sprayer is not available, use a paint brush to apply the insecticide. You can use 1% proposur (Baygon), 0.5% diazinon, 0.5% chlorpyrifos (Dursban), or 0.25% resmethrin.
Cover clean shelves. After the insecticide spray has dried, cover the shelves with clean, untreated shelf paper before you replace the food and dishes. Be sure not to use insecticide-treated shelf paper, since you've already sprayed the shelves.
Use secure containers. Now that your pantry is pest-free, be sure to store your food in clean, airtight containers that new pests will not be able to invade. Be sure to check your stored, dried products from time to time, especially if you don't use them very often. At the first sign of an infestation, remove the container from your pantry and either throw it away, cook it, or freeze it.
With planning and foresight you can prevent dealing with a pantry infestation. But even if one occurs, you can take care of it fairly easily by following the plan outlined above. Once you know what you're dealing with, you can take whatever steps are necessary to prevent a re-infestation. Keeping your pantry free and clear of all invaders can protect not only your food, but also your health. Hence, do whatever you can to keep those insect marauders from bugging you.