Varied carpet beetles are 1/10-inch long black beetles with irregular patterns of white, brown, and yellow scales on their hard wing covers. The adults are active in early spring after completing their development indoors. Attracted to sunlight, they fly to windows in early spring as they move outdoors to feed on nectar and pollen.
The hairy, caterpillar-like larvae prefer dark, protected places – drawers, stuffed furniture, closets, etc. They feed on a variety of natural products including wool, silk, and cotton; furs, feathers, and hair; processed meals and mixes; spices, cereals, crumbs; and dried pet foods. They also feed on accumulations of dead insects in ceiling light fixtures, wall voids, and attics, and shed pet hair. These insects are common in homes or buildings having problems with fall accidental invaders, such as cluster flies and boxelder bugs.
Carpet beetles are very difficult to control because they can develop on small amounts of food in many obscure places. A vacuum cleaner is the best control measure. Rooms where the insects are found should be cleaned thoroughly. Heat vents, corners, cracks and crevices along baseboards and moldings, suspended light fixtures, and other hard-to-reach areas are ideal for them. Cleaning removes both insects and potential food sources.
Cleaning is always the best strategy long-term; however, areas that cannot be cleaned can be sprayed with an insecticide labeled for indoor use. Use a product that lists carpet beetles on its label and closely follow the directions. Apply insecticides as spot, and crack and crevice treatments. Limit sprays to edges of floor coverings, under rugs and furniture, floors and walls of closets, shelving where susceptible fabrics are stored, cracks and crevices, and in other lint-accumulating areas.
by Lee Townsend, Extension Entomologist