Finding a beetle crawling across the floor or sitting on a windowsill doesn't necessarily mean you have an infestation. Many beetles wander indoors accidentally and cause no damage at all. Others, however, can infest food, natural-fiber fabrics or wood—and figuring out which type you've found is the first step toward solving the problem.
Where you find the beetle often provides the best clue. Tiny insects appearing in a bag of flour suggest a very different problem from small holes appearing in hardwood flooring.
Here are several common types of beetles homeowners may encounter and what to do if you find them.
- Carpet Beetles
Carpet beetles are common indoor pests, but the adult beetles aren't usually responsible for damage. It's their larvae that cause trouble.
Depending on the species, adult carpet beetles may be dark-colored or have mottled patterns of white, brown, yellow and black. Adults are frequently noticed near windows because they're attracted to light.
The hairy larvae feed on animal-based materials, including wool, fur, feathers and other natural fibers. They may damage rugs, clothing, upholstered furniture, blankets and stored fabrics. They can also survive on accumulations of hair, lint, dead insects and other organic material hidden in quiet areas of the home.
What to do: Vacuum thoroughly along baseboards, beneath furniture, around heating vents and inside closets. Inspect susceptible clothing and other natural-fiber items. If you repeatedly find larvae, shed larval skins or fabric damage, look for the source rather than simply removing the adult beetles you see.
A couple of adult carpet beetles near a window doesn't automatically mean your carpets are infested.
- Powderpost Beetles
Powderpost beetles are wood-boring insects, and the term is commonly used for several groups of beetles whose larvae develop inside wood.
True powderpost beetles in the family Lyctidae attack seasoned hardwoods and may turn up in hardwood flooring, furniture, paneling, lumber and other wood products. Adults are small and brown, usually less than 1/4 inch long.
The insects themselves can be difficult to spot. The more obvious clues are small, round exit holes and fine, powder-like material produced as larvae tunnel through the wood.
One common mistake is assuming every old hole means there's an active infestation. Old furniture and lumber may retain exit holes long after the beetles are gone. Fresh powder appearing around holes is more concerning and deserves closer inspection.
What to do: Determine whether the infestation is active and identify the type of wood-boring beetle before choosing a treatment. Depending on the situation, control can involve moisture management, replacing infested material or professional treatment. Finished or sealed wood can also affect which treatments are effective.
If structural lumber appears to be involved, professional identification is especially worthwhile.
- Multicolored Asian Lady Beetles
Lady beetles are beneficial outdoors because many species feed on aphids and other plant pests. One species, however, is particularly well known for becoming an indoor nuisance: the multicolored Asian lady beetle.
These beetles vary from yellow and orange to red, and the number of black spots can vary considerably—or spots may be absent altogether. A useful identification feature is the dark marking behind the head that often resembles an "M."
The problem usually develops in fall when the beetles gather on buildings and enter cracks and gaps in search of protected places to overwinter. They don't reproduce inside homes or infest food, fabric or wood.
What to do: Prevention works better than trying to eliminate them after they've entered wall voids. Seal gaps around windows, doors, siding, utility penetrations, fascia and vents, and repair damaged screens.
If beetles appear indoors, vacuum them rather than crushing them. When disturbed, multicolored Asian lady beetles can release a yellowish, strong-smelling fluid that may stain light-colored surfaces.
- Sawtoothed Grain Beetles
If tiny brown beetles are crawling around your pantry, inspect your stored foods.
Sawtoothed grain beetles are small, flattened beetles that infest a variety of dry foods. Despite the name, they aren't limited to grain. They may be found in cereal products, nuts, dried fruit, pasta, seeds and other stored foods. They can also infest dry pet food and birdseed.
Their name comes from the distinctive tooth-like projections along each side of the thorax, although these details can be difficult to see without magnification.
What to do: Don't limit your inspection to the package where you first spotted a beetle. Check nearby dry goods as well, particularly opened packages and foods that have been sitting undisturbed.
Discard infested products, vacuum cracks and shelf edges where food particles collect, and store replacement foods in tightly sealed containers.
Simply spraying the pantry won't solve a problem if an infested bag of cereal or pet food remains on the shelf.
- Drugstore Beetles
Drugstore beetles are another pantry pest with a surprisingly broad diet.
These small, oval, brown beetles infest many dried foods, including flour, rice, pasta, crackers, spices, dried fruit, chocolate and dry pet food. They're also capable of feeding on some nonfood materials.
Adult drugstore beetles can fly, so homeowners sometimes notice them around windows rather than directly beside the product where the infestation began.
What to do: Conduct a careful pantry inspection. Check rarely used baking ingredients, spices, pet treats and other dry products—not just flour and cereal.
Once you've found the source, discard the infested material and clean the storage area thoroughly. Transfer susceptible foods to containers with tight-fitting lids.
Don't Forget Pet Food and Birdseed
When pantry beetles keep returning despite a spotless kitchen, look beyond the kitchen cabinets.
Large bags of dry pet food and birdseed can support pantry pests and may sit open for weeks or months. Beetles can then spread from these products to other parts of the home.
Store these products in pest-resistant containers and periodically inspect older packages. The same advice applies to dried decorative foods, seeds and other plant-based materials kept indoors.
Identification Comes Before Treatment
One of the easiest pest-control mistakes is treating an insect before knowing what it is.
A carpet beetle, powderpost beetle and pantry beetle may all be small and brown, but they require completely different solutions. Spraying baseboards isn't going to eliminate beetles developing inside a package of food, and throwing away pantry goods won't solve a wood-boring insect problem.
Start with three questions:
Where are you finding the beetles? A pantry, closet, windowsill or piece of wood provides an important clue.
What evidence is nearby? Look for damaged fabric, holes and powder in wood, contaminated food, shed larval skins or large numbers of beetles gathering around windows.
Are you finding one beetle or many? A single insect may have wandered inside. Repeated sightings, larvae or visible damage are stronger signs that there's a source somewhere in the home.
Keeping Beetles Out of Your Home
There's no single prevention method for every type of beetle, but good housekeeping and home maintenance can eliminate many of the conditions that allow household pests to become established.
Vacuum areas where hair, lint and dead insects accumulate. Store vulnerable foods in sealed containers. Inspect secondhand wooden furniture and natural-fiber items before bringing them indoors. Seal exterior gaps that allow seasonal invaders to enter.
Most importantly, investigate recurring beetle activity instead of simply killing the insects you can see. Finding the source is usually what solves the problem.
If beetles continue appearing, you're seeing unexplained damage to wood or valuable belongings, or you can't confidently identify the insect, a pest management professional can determine what you're dealing with and whether treatment is actually necessary.
