The black carpet beetle (Attagenus unicolor) is the commonest of the carpet beetle species in the Edmonton area. Shed skins of the larval stage are the most frequently encountered symptom of infestation in the home. The reddish-brown, carrot-shaped larvae may attain a length of 9 mm (a third of an inch), with a distinctive tuft of long hairs at the tail end.

Adult black carpet beetles are oval, dark brown to black in colour and up to 5 mm (a quarter of an inch) long. Unlike their dark-loving larvae, they are attracted to windows or can be seen outside on bright sunny days feeding on the pollen of flowers.

The problem?

The larval diet of the black carpet beetle consists mainly of animal skins or animal based fibres like feathers, fur or woollen products. They often will be found behind baseboards feeding on accumulations of lint and hair or scavenging the remains of dead insects that collect around windows and vents.

Other species of carpet beetle prefer dried plant or stored food products, but are not commonly found here.

What You Can Do?

Infestations of these insects can be managed effectively through a combination of proper food storage and good house-cleaning and maintenance practices. Besides obvious things like food spill cleanup and refuse management, routine crack and crevice vacuuming in clothing storage areas, heat registers, window sills, light fixtures, and along baseboards will help, however, be prepared to dispose of the vacuum cleaner contents afterwards since it may contain live insects.

Check chests of drawers, old trunks, anywhere where woollens, feather, fur or any other animal fibre products may be stored. Infested articles should be laundered or frozen for several days to curb any further feeding damage.

Insect proofing the home against entry of the adult beetles from the outdoors includes ensuring the proper function of external door seals and window screens, especially on sliding windows; caulking external cracks in walls and around window and door frames, and checking if vents to the outside can be screened or valved as in the case of a dryer vent.

In persistent infestations, consider the use of crack and crevice applications of diatomaceous earth, a low toxicity insecticide dust that provides effective long-lasting control of these insects. Diatomaceous earth is available at seed stores, garden centres and other insecticide retail outlets.