Plaster beetles are also known as mold beetles because they thrive in damp environments. Scientists call them Minute Brown Scavenger Beetles. There are several species. They are members of the beetle family Lathridiidae.
Plaster beetles are small insects. Adults are usually less than 1/8″ long. The color can be yellowish brown, reddish brown, or dark brown. The adult beetle body shape varies according to the species. There are several rows of tiny holes on the wing covers. The wing covers stay folded over the back, so it looks like the beetles have perforated backs.
Plaster beetles feed on mold. In nature, they are found under logs, in stumps, and in decaying material. They are sometimes found in the nests of subterranean termites because they find dampness and mold there.
These beetles invade homes where there has been a moisture problem. They will move into damp basements and attack moldy items that are being stored. They will move into attics where the roof has been leaking, or into damp crawl spaces.
Controlling moisture and eliminating mold are the keys to controlling plaster beetles. Inside homes, check plumbing for leaks. Bath traps are common high-moisture areas. It is sometimes necessary to install a vent to allow air circulation in the tub trap. Water stains on ceilings are evidence of roof leaks.
If crawl spaces are damp, check to make sure vents are open. Shrubs should not block crawl space vents. A dehumidifier can often help in damp basements. Check gutters to be sure they are clean and working properly. Down spouts should drain away from the foundation.
Many people find it easier to have a pest control professional make the inspection and find the source of the infestation. He or she can advise if a plumber or any other trades are needed.
After the moisture problem has been corrected, it is sometimes necessary to apply insecticide to eliminate plaster beetles. Insecticidal dust can be effective inside walls and in other void spaces. Contact insecticide can be effective for eliminating active adult beetles. The pest control professional will have the products and equipment necessary to make these applications.