Powderpost
Beetles Make your House Look Like it was Shot by Buckshot
If you have a house with exposed wood as joists, or even oak flooring, and you see many little holes as if the area was hit by a shotgun, you may be encountering powderpost beetles. While there are several types of beetles that may be called powderpost, true powderpost beetles are of the family Lyctidae, which includes 66 species. In the U.S., only about six species are of concern. While holes may be present in hardwoods (such as oak) and softwoods (such as pine) lyctid powderpost beetles only attack the sapwood of hardwoods. Lyctid powderpost beetles are easily transported from location to location since they readily infest furniture and bamboo, which is most prevalent as offices and families relocate. There is no state in the US that is free of lyctid powderpost beetles.
The adults, though rarely seen, are small, reddish-brown to black up to just over a quarter of an inch in length. Larvae and eggs are rarely seen as well. In the case of this pest, the damage is the most common sign of infestation.
The infested wood is commonly characterized by small, narrow galleries packed with extremely fine flour-like frass. In active infestations, frass tends to sift from the holes where the adults emerge forming small piles of the dust. Dust may also fall from wood with inactive infestations when jarred so frass alone is not a sign of active infestation.
The reason the lyctid powderpost beetles are only found in hardwoods is due to the need for the eggs to be deposited in structures or pores large enough for the eggs. Such pores are only found in hardwoods. The hatched larvae will then feed on nutrients in the wood but generally such nutrients are only found in wood less than ten years old. While log cabins may have evidence of such infestation, if the logs are softwood, the infestation is not due to this type of beetle.
While lyctid powderpost beetles will generally not affect the structural integrity of buildings, since such structural wood is generally softwood, the beetles may attack doors, decorative pieces, furniture, window frames, and cabinetry, which can lead to expensive repairs.
Treatment for active infestations may be topical or by fumigation depending on the severity and the location. Your pest management professional is trained to look for signs of infestation and can provide a treatment method that is right for you.