How do they get there? While it’s possible that pests such as beetles or moths may already be in items we bring home from the store, DeVries says the majority show up after the food goes into your cabinets — “crimes of opportunity.”
Bugs that are attracted to your food may already be inside, or they may enter through open doors, crevices or cracked window screens.
Packages that are partially open, such as bags of flour or sleeves of cookies, are invitations to insects, as are thin cardboard boxes with narrow gaps, such as pasta or crackers. Anything that spills or leaks — looking at you, honey and sugar — can attract them, too.
What do they eat? Some pests can penetrate the seed coat of plants, which is why whole grains are particularly attractive to certain species, DeVries says. Others need the grain to be cracked open, as in many refined flours, pasta, cookies, cereal, crackers, etc. Dog and cat food and bird seed are also common sites of infestations.
“Inside buildings, household ants feed on sugar, syrup, honey, fruit juice, fats, and meat,” says the University of California Division of Agriculture and Natural Resources.
How should you get rid of them? Usually when you come across moths or beetles in the pantry, what you’re finding are the adults, DeVries says. Once you see a lot of them, 10 or 20, you probably have an infestation.
Much as eliminating the breeding site of fruit flies is the only sure way of eliminating those common pests, getting rid of the source is key to saying goodbye to beetles and moths. Systematically sort through all the food in your pantry and open the packages. Sift grains or flours to spot interlopers. Anything that appears to be heavily infested should be tossed. Often, the damage is limited to one or two items, according to DeVries. If you want to try to salvage items — or want to ensure that what appears to be free of pests in fact is — you can freeze them at 27 degrees or, ideally, colder for three to seven days; the longer, the better, says the Illinois Extension at the University of Illinois-Champaign. Or you can heat the food at 140 degrees in an oven for an hour, though keep in mind that most home ovens cannot be set that low.
Getting rid of the infested food can go a long way toward eliminating an infestation, but vacuuming and/or wiping down the shelves with warm, soapy water is never a bad idea.
Much of the same advice applies to ants. Once you find what is attracting the ants, says the University of California Division of Agriculture and Natural Resources, remove it. Vacuum the ant trails and clean with warm, soapy water. This gets rid of the pheromones the insects would follow to get back to the food source, DeVries says. Then try to find and seal up the points where they’re coming in. If they persist, you can use ant bait, either in stations or other forms, such as gel, but try to save it for serious infestations. If you can, use bait outside near the entry points so that you don’t inadvertently attract more ants inside.
What don’t you need? Insecticides, DeVries says. Insecticides, especially sprays, near food and food prep surfaces pose a greater danger to you than pantry pests, which are a nuisance but not a general health concern. For beetles and moths you encounter, use a fly swatter or vacuum to eliminate them, or shoo them out the door.
How can you prevent them? DeVries suggests a three-pronged approach to prevention: turnover of food, stopping the intruders from coming in and hard-sided containers.
First, use the food in your pantry in a timely manner. Beetles and moths take awhile to settle in, so if you’re using your flours, pasta and snacks over the course of a few weeks or even months, you’re probably okay. It’s old items shoved in the back that remain untouched for a long time that are particularly problematic. Periodically sort through what you have to see what needs to be used or tossed (or composted).
Avoid leaving doors or windows without screens open. Patch broken screens and seal up gaps around your baseboards, doors and windows.
Keeping your food in hard-sided, airtight containers is “a very simple, very easy” step you can take, DeVries says. That deters pests, of course, with a side benefit of keeping your food fresher for longer. Containers or not, if you notice a spill, clean it up right away.