Getting rid of spider beetles requires finding and removing whatever they’re feeding on, then cleaning thoroughly to eliminate eggs and larvae you can’t see. These small, round beetles look surprisingly like spiders at first glance, with long legs and a humped body. They feed on stored foods and organic debris, and a single female can lay up to 100 eggs near a food source. The good news: once you remove that food source, the infestation collapses.
What Spider Beetles Feed On
Spider beetles are stored-product pests, meaning they eat dried foods in your pantry and organic matter tucked into hidden spaces. Both the adults and their small, grub-like larvae feed on the same materials. Common targets include grain products, flour, cereals, dried fruit, seeds, sugar, spices, and pet food. They’ll also feed on less obvious things: old rodent droppings, dead insects, bird or rodent nesting material in attics and wall voids, and even accumulations of crumbs behind appliances.
That last category is important because it explains why spider beetles sometimes seem to appear out of nowhere. You may have cleaned your pantry spotlessly and still see beetles crawling around. The actual breeding site could be a forgotten bag of birdseed in the garage, mouse droppings in a wall void, or a dead-insect buildup in your attic. An active or past rodent problem is one of the most common hidden sources of spider beetle infestations.
Find the Source First
Before you do anything else, you need to locate where the beetles are breeding. Start with your pantry and kitchen. Pull everything off shelves and inspect each package of dry goods. Look for small holes in packaging, fine webbing, or tiny grub-like larvae curled into a C shape. Check items you may have forgotten about: that bag of whole wheat flour pushed to the back, an old box of oatmeal, decorative dried flowers, or a bag of dog treats.
If you don’t find anything in the kitchen, expand your search. Check the attic for old nesting material from birds or rodents. Look in crawl spaces, basements, and wall voids where mice may have left droppings. Inspect stored boxes in closets, especially those containing dried goods, wool, or old books. Spider beetles are nocturnal and prefer dark, undisturbed spaces, so the breeding site is almost always somewhere you don’t look regularly.
Remove and Clean Everything
Once you find infested material, throw it away immediately in a sealed bag that goes directly into an outdoor trash bin. Don’t leave it in a kitchen wastebasket. For items stored near the infested material but showing no visible signs of beetles, you have two options: discard them to be safe, or treat them with heat or cold (more on that below).
After removing infested items, vacuum every surface in the affected area. This means shelf surfaces, cracks, crevices, corners, and the undersides of shelves. Spider beetle eggs are tiny and stick to surfaces, so vacuuming is more effective than wiping. Use a crevice attachment to get into gaps where shelving meets the wall. After vacuuming, wipe shelves down with warm soapy water and let them dry completely before restocking.
If the source was in your attic, crawl space, or wall voids, clean out all rodent droppings, nesting debris, and dead-insect accumulations. This step is non-negotiable. Leaving organic debris in hidden spaces gives the beetles exactly what they need to re-establish.
Kill Beetles With Heat or Cold
For items you want to save rather than throw away, temperature treatment reliably kills spider beetles at every life stage, including eggs.
- Freezing: Place the item in a sealed plastic bag and put it in your freezer at -4°F (-20°C) for seven days. Most home freezers reach this temperature. This kills all life stages, including eggs, which are the hardest to destroy.
- Heating: Set your oven to its lowest temperature setting, typically around 150 to 170°F. Place items inside for 45 minutes to one hour. Thicker items like wooden objects may need longer. Turn off the heating element and let everything cool inside the oven for an additional hour before handling.
Freezing works well for spices, dried herbs, flour, and other pantry staples you don’t want to waste. Heating is better suited for non-food items like decorative pieces, books, or wooden objects. Neither method affects the quality of most stored foods when done correctly.
Seal Your Storage
The single most effective long-term prevention step is switching from cardboard boxes and paper bags to rigid, airtight containers. Spider beetles (and their larvae) can chew through paper and thin plastic packaging. Glass jars with screw-top lids, heavy plastic containers with snap-on lids, or metal canisters all work. Every grain product, flour, cereal, dried fruit, seed mix, sugar, and pet food in your home should be in one of these containers.
This does two things at once. It prevents beetles from reaching your food, and if you accidentally bring home a product that already contains eggs (which is how many infestations start), the problem stays contained inside one jar instead of spreading through your entire pantry.
Seal Entry Points for Rodents
Because rodent activity is so frequently linked to spider beetle infestations, sealing gaps that let mice and rats into your walls, attic, and crawl spaces is a critical prevention step. Look for gaps around pipes, vents, utility lines, and foundation cracks. Mice can fit through openings as small as a dime. Steel wool packed into gaps, caulk for small cracks, and hardware cloth over larger openings are all effective.
Even if you haven’t seen a mouse in years, old nesting material and droppings left behind can sustain spider beetles for a long time. Cleaning out these remnants and then sealing the entry points prevents both the rodent problem and the beetle problem it feeds.
How Long Until They’re Gone
Spider beetle development from egg to adult takes anywhere from two weeks to over three months depending on the species, temperature, and humidity. This means you may continue seeing occasional adults for weeks after you’ve cleaned up, because eggs or larvae that were already developing will finish their cycle. Don’t panic if you spot a few stragglers. As long as you’ve removed the food source and cleaned thoroughly, those beetles have nothing to feed on or lay eggs in, and the population will die out.
If you’re still seeing new beetles after two to three months and the numbers aren’t dropping, you likely missed a breeding site. Revisit the inspection steps and expand your search to less obvious areas: behind baseboards, inside dropped ceilings, in stored cardboard boxes, or in the spaces between walls where old rodent nests may be hidden.