This beetle is a native insect in western North America.
The common name of this beetle is a possible cause of confusion with the unrelated “Old” house borer that is found in the eastern U.S. The “New” house borer is a western species found from Canada south to California and most western states, and it feeds only on dead or dying trees. However, because lumbering practices often salvage trees recently killed by fire or bark beetles the New house borer may be present in lumber used in construction. Females deposit eggs only on the bark of a standing tree or a log, and do not reinfest structures once they have emerged. It takes 2 years for the larva to complete its growth in the wood, but once the wood dries the larva cannot survive. Only those larvae that are nearly full grown and can pupate will survive in the milled lumber, and thus will emerge within a few months to a year after the wood is used in a new structure. The beetles infest only conifers, but the adults will bore through any other materials over the infested wood in order to emerge, including sheetrock, paneling, hardwood flooring, or linoleum.
The adult beetle is about 1 inch long with an overall dull dark brown to dark gray color. Its wings are relatively narrow with parallel sides and the thorax is short and rounded. Several raised ridges on each wing cover run from front to back. The antennae are medium length and in males are about 2/3 the length of the body.
Characteristicts Important to Control:
The best control is to allow the infestation to run its course and then to repair any holes made by the adult beetles. If a heavy infestation is causing unreasonable damage a fumigation of the structure may be necessary.