Pantry Pest Control
Like all other creatures, insects have to eat; and some of them have adapted to eating the very same stuff that people eat. In fact, some of them eat the food that we have stored in our pantries, which is why we call these insects, as a group, “pantry pests.”
Pantry pests include various species of beetles, weevils (basically beetles with snouts), and moths that feed on stored foods. There are dozens of these insects: The ones on this page, like the adult and larval stages of the Indian Meal Moth on the right, are just a few of the more common ones.
The names of specific pantry pests often reflect their preferred or usual foods. Some pantry pests prefer specific types of foods, such as rice or corn, for example; and some prefer whole grains while others prefer meal or flour. But the truth is most stored-product pests aren’t very particular and will eat whatever is available.
“How Did These Bugs Get in my Food?”
That’s a question we hear a lot. Usually the answer is that they hitch-hiked in a package of food that we brought back from the market, and then spread from there. The food may have been infested at any point along its manufacture and distribution, starting with the farm where it was grown. Usually it’s impossible to pinpoint the exact source.
What we do know is that once these pests get in your home, they usually spread; and what started as a few bugs in a bag of pasta can rapidly become a major pest problem.
General Prevention Measures for Stored Product Pests
You can reduce the chances of getting an infestation of stored product pests by following a few simple rules. The most important of these is to store food in tight-closing containers. Clear glass or plastic containers with tight-fitting lids will work, but so will heavy-duty (freezer-rated) zipper-type plastic food storage bags. The advantage to using clear containers is that you can see the bugs through the containers.
In addition to proper storage, proper sanitation will help reduce the chances of an infestation becoming established in your home. Spilled products inside cupboards should be promptly cleaned up, and the insides of pantries and cabinets regularly cleaned. If any product has gotten into the cracks and crevices, it should be removed. A strong vacuum cleaner is a good way to do this.
The use of sticky traps as monitoring devices is also a good way to keep an eye on things to make sure that a pest infestation isn’t developing. Unless you know that you have a particular pest problem, a general-use stored product pest trap that attracts a variety of insects is a good way to go.
One thing that it’s important to point out is that the insects we’re going to talk about on this page won’t kill you. They may (or may not) make the food taste bad, but you’re not going to die or get sick if you accidentally ingest them. So try to relax, and don’t go throwing away all the food in the house. Putting all your food in clear containers or zipper-type plastic bags is a good way to try to narrow a pantry pest infestation down. Throwing away all the food in the house is an overreaction and is unnecessary.
Common Pantry Pests in the Portland and Vancouver Areas
There are dozens of insects that commonly infest stored foods in our area, but the ones we’re going to introduce you to here are some of the more common ones. One thing we have to mention, though, is that these insects tend to be very tiny. Most of the beetles and weevils, for example, are only about the size of a pinhead. That’s important to keep in mind because the pictures here are close-ups.
Indian Meal Moths
Indian meal moths average around 3/8 of an inch as adults, and are among the most common moths infesting stored foods. They’re easy to identify because of their distinct wing coloration. Their wings are divided into distinct sections of tan or gray toward the front and brown toward the rear, with dark bands going across. They fly more often at night than in the day.
Although named for corn (“Indian meal”), Indian meal moths can infest practically any plant-based stored food. They prefer ground meal or flour, but will also infest cereals, pet foods, nuts, dried fruits or herbs, bird seed, and many other foods.
As is the case for quite a few pest moths, adult Indian meal moths aren’t the ones that do the damage. In fact, adult Indian meal moths don’t feed at all. They emerge from pupation, lay eggs, and usually die within a few days to a week. The eggs will hatch into larvae, and it’s the larvae that will actually infest the food.
That’s why the fact that you’re not seeing the adult moths any more doesn’t mean the problem has “gone away by itself.” Chances are the adults laid eggs before they died, and it’s also possible that there are other insects in the larval or pupal stages already infesting your food. So at a minimum, storing your food in tight containers and inspecting it for insect larvae before using would be a good idea even if you’re no longer seeing the adult moths. (Unless, of course, you want the extra protein in our diet.)
Rice Weevils, Maize Weevils, and Granary Weevils
Rice weevils (shown in picture) and granary weevils are tiny (about 1/10 inch) weevils with impressively long snouts. Maize weevils are similar to rice weevils, but are a bit larger. All three weevils have a strong preference for whole grains, nuts, and seeds, which are their natural foods. Adult rice weevils and maize weevils are attracted to light and can fly. Adult granary weevils cannot fly.
Both the adults and the larvae of these weevils feed on stored products. Although they’ll eat pretty much any grain-based food if they have to, rice weevils, maize weevils, and granary weevils must complete the larval stages of their lives inside a kernel or seed and pupate there. They can complete this stage in whole grains, nuts, seeds, or dry beans. On rare occasions, they can complete this stage in tightly-compacted grain, but that’s the exception rather than the rule.
When they complete pupation, the adult weevils eat their way out of the kernel, nut, or seed, emerge, and immediately look for a mate. Females may live several months and lay hundred of eggs.
All three of these weevils have an interesting habit of “playing dead” when disturbed. They draw their legs up to their bodies and remain silent and still until the threat has passed.
Drugstore Beetles and Cigarette Beetles
Drugstore beetles (shown here) and cigarette beetles are closely related beetles that average about 1/10 inch in length as adults, and that infest a wide variety of stored foods. They’ll eat pretty much anything, including flour, meal, cereal, dried herbs and spices, pet foods, leather, fur, and feathers. Both beetles often are pests in museums, where they eat books, manuscripts, tapestries, and even bones.
Drugstore beetles got their name from their habit of infesting the herbs and other substances traditionally used to make medicines. They are resistant to many poisonous compounds that would kill other insects.
There are two easy ways to tell drugstore beetles and cigarette beetles apart: the last three segments of a drugstore beetle’ antennae are clubbed, whereas the cigarette beetle’s antennae are serrated; and drugstore beetles have longitudinal grooves on their wing pads, whereas cigarette beetles have smooth wing pads. Both beetles are able to fly, and neither feed as adults. The larvae are the stage that do the damage.
Sawtoothed Grain Beetles and Merchant Grain Beetles
Sawtoothed grain beetles are named for the serrated sides of their thoraxes, which resemble the teeth of a saw. They’re about 1/8 inch long as adults. Sawtoothed grain beetles are almost identical to merchant grain beetles in appearance and have fairly similar biology. Merchant grain beetles can fly, however, whereas sawtoothed grain beetles cannot.
Both of these beetles feed on a wide variety of foods including cereals, cornmeal, cornstarch, rice, dried fruits, flour, oatmeal, pasta, sugar, herbs, spices, dried meats, and many others. They do not feed on intact whole grains. Both larvae and adults of these beetles feed, and because adults can live for months (or even years, under ideal conditions), infestations can grow quite rapidly.
Sawtoothed and merchant grain beetles are able to penetrate most retail packaging materials. If you have a known infestation of either of these beetles, it’s vital to store all susceptible foods in insect-proof containers, such as glass or plastic jars with tight-fitting lids, or freezer-grade, zipper-type plastic bags. (The beetles can penetrate thinner, sandwich-type bags.)
Although not commonly considered “pantry pests,” clothing moths have similar enough biology that this was as good a place as any to talk about them.
Clothing moths feed on an animal protein called “keratin” that’s found in the hair, horns, nails, claws, hoofs, feathers, and scales of reptiles, birds, and mammals. In homes, they commonly feed on clothing, carpets, furs, tapestries, blankets, upholstery, piano felts, brush bristles, and many other items.
Moths cannot complete their normal life cycle on clean, processed wool. It must be contaminated with some nutritional supplement such as food, beverage, sweat or urine stains. Such stains provide the proteins, the mineral salts and the vitamin B complex essential to the moth. That’s one reason it’s important to wash or dry-clean clothing before putting it into storage. (The other is so the clothing doesn’t smell bad.)
Stored Product and Pantry Pest Control
At Bugaboo Pest Control, we use a variety of treatment measures to wipe out stored product or pantry pests, depending on the type of pest and location and extent of the infestation. These methods usually include:
Inspection and Consultation
We can help you identify the kind of pest you have and identify infested products so you can discard them.
These traps contain attractants that mimic the chemical messengers that insects use to attract mates. Usually the traps attract the males, who get stuck to them, and therefore cannot mate.
Insect Growth Regulators (IGRs)
These products disrupt the insect’s normal development. Some interfere with the insect’s ability to molt, while others prevent immature moths from developing into reproductive adults.
In most cases, the use of insecticides for pantry pest control is unnecessary and not recommended. Finding and eliminating the source and using the above methods will eliminate most infestations.
Please contact us for more information about pantry pest and stored product pest control, or any of our fine pest control services.