Despite the differences in the biology and habits of the many beetles, weevils, and moths that infest stored foods, the treatment needed to solve these pest problems is fairly similar regardless of the particular insect.
Very often, infestations of stored-food pests can be controlled non-chemically. When pesticide treatments are necessary at all, they should be considered an adjunct to the treatment, rather than the treatment itself. Non-chemical measures are much more important, even if pesticides ultimately are used.
Proper control of stored food pests begins with the following steps
Any foods known or suspected to be infested must be discarded, and they must be discarded in such a way that the infestation can't spread to uninfested food. The easiest way to do this is to discard the products into heavy-weight garbage bags, and then immediately take out the garbage once all the infested foods are in the bag.
If you live in a place where you can only take out the garbage on certain days, then either clean out the pantry on one of those days or seal each individual item to be discarded in a freezer-weight zipper type storage bag before placing it in the trash. Use bags designed for storing foods in the freezer.
Most than likely, there will be some food packages that you're uncertain about. The best way to deal with these from a pest-control point of view would be to treat them as infested and throw them out. At a minimum, you should quarantine these foods. You can use the gallon-sized freezer storage bags as a temporary way to do this.
Because many pantry pests can get through freezer bags if they really want to, they're not a permanent solution. Their purpose is to contain any insects temporarily to give you time to inspect the products before deciding whether to keep them or throw them out. You'll need to inspect the quarantined foods every day or two. If you see signs of insect activity, then discard those items, freezer bag and all.
Completely empty the cabinet where the infested food was stored, as well as the cabinets adjacent to it. Thoroughly vacuum the entire cabinet, paying special attention to the nooks and crannies. Remove any drawers in the cabinets and vacuum both the drawers and the places where the drawers fit, including the drawer slides. Discard the vacuum cleaner bag when you're finished in case it contains eggs, pupae, or adult insects.
Next, thoroughly inspect the entire pantry for pupae that may have adhered to the corners, cracks, and crevices. If you find any, scrape them off.
At this point, you have a decision to make. You can either wash the interior of the cabinet with hot water and a cleaner like Kleen Free Naturally, Green Power Insect Clean, or Pure Cold Pressed Orange Oil Concentrate, any of which have natural insecticidal activity; or you can treat the insides of the cabinets with any conventional residual insecticide that's labeled for use in kitchen cabinets, such as Hot Shot.
The arguments against treating your cabinets with an insecticide are, firstly, that if you discarded all of the infested foods and thoroughly cleaned the cabinets, no insects should be left to kill; and secondly, that no over-the-counter insecticide will kill the eggs or pupae of pantry insects, anyway, making the application an unnecessary and pointless use of a pesticide.
The argument in favor of using an insecticide is that if you missed any infested foods and kept them rather than throwing them away, or if you missed any insects during your cleaning of the cabinets, the residual insecticide will kill those insects once they contact it. Without the insecticide, you'll have to start the whole process all over again and throw away even more food.
My advice is that you consider the use of an insecticide in light of how bad the infestation was and how much you'd hate to do the whole job all over again. If you found bugs in one box of pasta, promptly threw it out, and haven't seen them anywhere else, then maybe you'll want to take the chance and skip the insecticide. But if your infestation wasn't isolated to any single product, probably you're better off treating the cabinet with an insecticide labeled for that use.
Keeping your food free of insects involves a bit of a lifestyle change, and an important part of that is to store all susceptible foods (basically anything that's not in a metal can) in insect-proof storage containers. My favorite insect-proof food-storage containers are airtight large glass jars, stainless steel canisters, or acrylic canisters with tight-fitting lids.
What I do is immediately transfer susceptible foods like flour, pasta, cereal, and so forth to airtight, insect-proof containers as soon as I bring it home from the supermarket. This serves three important purposes: It prevents the food from becoming infested with bugs, it prevents foods that were already infested when I bought them from spreading the insects to other foods, and it prevents me from eating infested foods because the bugs will be obvious when I open the packages. As an additional benefit, I can return any infested foods to the supermarket for a refund if it's worth the trip.
Pantry pest traps are an essential final and ongoing step in any pantry pest-control job. They should be installed only well after the cleaner or insecticide you applied has completely dried. I like to give it 24 to 48 hours because most cleaners and practically all insecticides are repellent to insects. You don't want the trap, which is designed to attract insects, to be contaminated with a solvent or insecticide that repels insects.
Pantry pest traps have two purposes. The first is as a control device to catch any insects that may have slipped past your inspection and cleaning or who may emerge from pupae that you missed. The second is to serve as monitoring devices to quickly identify subsequent infestations.
Insect monitoring traps contain no pesticides, but they do have label instructions that have to be followed with regard to the insects they are designed to attract,their placement, and their effective lives once they're opened. Choose traps that include the pest you're trying to control on their label, use them in accordance with the label instructions, and replace them within the label-specified replacement intervals. Professional exterminators write the installation dates and the replacement dates on every trap they install, and so should you.
Related Page: Commmon Pantry Pests