Carpet Beetles are a fairly common pest. We receive many calls us about this insect. Though these insects will do damage to fabric, they may be a pest in food products as well. Carpet beetles occur naturally outdoors and come into building from there. They may enter through improperly sealed or improperly screened doors and windows.

There are two basic groups of Carpet Beetles: the Black Carpet Beetles and Varied, Common and Furniture Carpet Beetles. The adult Black Carpet Beetle, as the name suggests, is black in color and oblong shaped and ranges in size from 1/8" up to 3/16" in length. The other three, though about the same size, will have a variety of different wing color patterns and are somewhat more oval in shape. Carpet Beetles go through complete metamorphosis which includes egg, larvae (crawling stage), pupae (cocoon) and adult (beetle).

Larvae of Carpet Beetles are fairly distinctive. They are quite hairy and are striped tan and white in color. There may be tail bristles (hairs) visible at the back of the insect as well.  Inspection commonly reveals either live larvae or sometimes cast skins of the larvae. It is this stage of the insect that actually ingests the fabric or food.

Finding Evidence

Carpet Beetle larvae may damage carpeting, clothing, hair, fur and animal hides. They will also feed on dead animal carcasses. As stated above, they may also be found in food products including milled products such as pastas, cereals, nuts, etc. Most homeowners spot the larvae crawling along a surface somewhere. They will wander about in areas away from where they feed. They will chew irregular holes in fabrics including carpeting, but often feed at the nap of the fabric without eating the base threads.

A common food source for carpet beetles may be pet hair. In areas around or behind furniture, accumulation of pet hair may provide ample food for this pest.

Although one may find beetles as well as larvae, we frequently see larvae being brought to us as specimens. Cocoons are rarely found as they tend to blend in with the fabric, making them difficult to spot.

Dealing with the Problem

These insect may be difficult to control. You can discard affected items or have them dry cleaned as needed. If a significant number of garments have been affected, ask the dry cleaner about a bulk rate. Removal of pet hair or fur with thorough vacuuming is helpful in reducing possible food sources for the larvae. Carpeting may be dry cleaned as well. You may want to dispose of the vacuum bag afterward as a precaution.

To control both the larvae and/or adults (beetles), a residual insecticide such as Allpro Bug Killer Spray may be applied as a pin stream (jet) to baseboards and along the carpet backing up to six inches from the edge of the carpet using a coarse fan spray. Wall to wall carpeting will need to be pulled off of the tackless strips to permit such application. Also, treat using the pin stream around both sides of the tackless strip itself to control any insects which may be hiding in that area. Finally, treat any other moldings such as around window frames and door frames.

Other harborages such as dressers or night tables should be treated inside around all corners where the larvae may hide as well as inside the corners of drawers and even on the bottom of drawers where gaps are present. Inside closets, treat corners including around window and door frame moldings and gaps alongside and above and below shelving.

If the infestation is severe, monthly applications of AllPro Bug Killer Spray may be needed.  Consider at least one follow up treatment after 30 days based on observation of the situation.

If a large number of beetles are present, Pro Control Plus, a room fogger, may be used to kill exposed insects. One six ounce can covers 5,000 cubic feet (length x width x height) of unobstructed area (a doorway is considered an obstruction).

Finally, we offer Gentrol IGR Concentrate as the least toxic approach for this insect. An IGR is an Insect Growth Regular. This product will affect the larval stage of Carpet Beetles. The result of exposure to Gentrol is that when affected larvae enter the pupae stage of development, their growth stops and they do not emerge as adults. This product has a very low level of toxicity and does not affect people in the same ways that it affects insects. The one ounce bottle of Gentrol will make one finished gallon.

Gentrol may continue to be effective for up to four months so that reapplication is not required on a monthly basis. Gentrol may be combined with the Allpro product to simplify the application, but it will degrade within 48 hours once it is diluted. Therefore, one may choose to mix the Gentrol separately and in smaller amounts to stretch the use of the product.