Series: Insects commonly submitted to the OSU Insect ID Clinic

While you’re sheltering in place at home right now, you’re probably noticing some of the critters sharing your home office with you. A cellar spider up there in the dim corner nooks of your kitchen ceiling. A stink bug crawling along the windowsill, looking for a way out. A crane fly bobbing along the wall. Not all who share your space will be obvious, but there are probably some telltale clues that miniscule busybodies are at work. You might not mind the occasional silk strands spanning a shelf, or the soft batting of a moth trapped within a light fixture. But when you start pulling your spring clothes out of storage and discover someone has been nibbling on a shirt, you do mind!

Who could it be? Certain dermestid beetles, commonly known as carpet beetles, are some of the usual suspects for fabric damage in homes, and apparently they are not well recognized, as they’re one of the more common insects submitted to the OSU Insect ID Clinic. Two species are frequently reported in Oregon homes, the varied carpet beetle (Anthrenus verbasci) and the black carpet beetle (Attagenus unicolor). In the great outdoors, adult carpet beetles are mainly spotted on flowers, munching pollen and serving a minor role as pollinators. Adults take flight in search of food and suitable spots to deposit eggs. Inevitably, they find their way into our homes.

Varied carpet beetle on flower

Carpet beetles aren’t trying to get into your home, but they will accidentally wander in through open doors and windows. Or maybe you carried them inside yourself, hidden in freshly cut flowers or on dry pet food.  Once in, carpet beetles are well-adapted to survive in our dry, barren indoor environments. Females find dark, enclosed spaces (closets, behind furniture, under carpets and floorboards, etc.) to deposit their eggs. Within a week or two, trouble hatches. Carpet beetle larvae set forth, in search of a meal. In the wild, dermestid larvae are scavenging generalists, consuming things like dead insects, beeswax, feathers, and other dead plant and animal materials. Indoors, carpet beetle larvae will feed on any morsel of animal origin, including woolen carpet and clothing, furs, leather, pet hair, lint and dead insects. Females lay their eggs near an immediate food source, but once larvae exhaust their initial meal, they’re capable of ranging relatively long distances in search of the next bit of snack crumbs, dead cricket or forgotten wool sock in the dark corners of your closet.

Varied carpet beetle on carpet

Varied carpet beetle adult, Anthrenus verbasci.

wooly bear carpet beetle larvae feeding on Kibble

“Wooly bear” carpet beetle larvae feeding on dog food kibble (photo © Matt Bertone).

Black carpet beetle adult

Black carpet beetle adult, Attagenus unicolor.

Black carpet beetle larva on carpet

Black carpet beetle larva on carpet.

When carpet beetles become pests

Carpet beetles have the potential to become pests if they start reproducing in your home (repeat appearances of adults, or you find larvae). Here are some basic steps to help with prevention and management of carpet beetles. If you need additional guidance for a widespread infestation, check out some of the additional extension resources listed below, or contact the OSU Insect ID Clinic for advice.

Prevention ideas:

  • Identify and eliminate food sources.
  • Reduce potential breeding sites with regular cleaning of spilled food, accumulated lint and hair, dead insects, etc.
  • Use insect-proof containers when you store food, woolens, furs and other susceptible items that larvae can feed on.
  • Use screen doors/windows to keep adult beetles out during warm months and seal other potential ways in.
  • Watch for telltale damage signs to clothing, furnishings, etc.

Control and management ideas:

  • Remove and destroy or treat infested materials.
  • You can use temperature treatments for infested objects. Kill eggs and larvae by storing small items in a freezer for 48 hours or heat-treat them at temperatures above 120 degrees F for several hours.
  • Infested clothing can be dry-cleaned.