During the past couple of weeks many homeowners have been surprised to find tiny brown beetles all over their homes. We have dubbed this beetle the "new house beetle" because it is so commonly reported by owners of newly built houses. The beetle is a common fungus beetle known as the foreign grain beetle.

Foreign grain beetles are oblong, reddish-brown and only 3/32 inch long. A distinguishing feature seen with magnification is the presence of tiny knobs or bumps on the front corners of the thorax, the segment right behind the head. The beetles are strong fliers and they are attracted to lights.

Foreign grain beetle adults and larvae feed on molds and fungi, and not on grain as the name would imply. Almost any mold or fungus growth may support their growth, though they are common in damp or spoiled grain.

However, as indicated above, foreign grain beetles are most frequently discovered as an unwanted house-warming guest in newly constructed homes. The beetles come from inside walls where molds are growing because of moisture that was sealed into the walls during construction. This moisture could come from wood left outdoors and exposed to rain before or during building, rain that blew into the house before it was “closed in,” or moisture from drywall compound applied over sheetrock. Beetles emerge from the new house walls for a period of several weeks until the house completely dries out. Problems with this pest are usually self-limiting as the seasons change and as moisture trapped in new houses dries out naturally.

Foreign grain beetles are a nuisance and annoyance but do not harm anything within the home. They cannot bite or sting, they do not attack plants, furniture or the house structure, and they do not infest stored food products.

Knowing the name and habits of the foreign grain beetle may make them more tolerable, as does knowledge that they will disappear in time without the use of pesticide. Vacuum or sweep up and discard beetles as they emerge. Flying insect aerosol sprays give only very temporary relief from these beetles. Application of residual crack and crevice insecticides is not very effective according to numerous observations, but may offer some benefit.