What indicates the presence of powderpost beetles in wood surfaces?

The presence of powderpost beetles in wood surfaces is primarily indicated by the small "shot hole" exit openings. These minute holes are characteristic of powderpost beetle activity, as adult beetles emerge from the wood after completing their larval development. The term "shot hole" refers to the small size of these exit openings, which can be easily overlooked if the wood's condition is not closely examined.

While larger exit holes may be indicative of other wood-boring insects, such as larger beetles or pests, powderpost beetles are known for creating these smaller, more discrete exit holes. Additionally, discoloration around the holes may occur as a secondary effect, but it is not a definitive indicator on its own. Crumbling wood structure could also signify a problem with wood integrity but doesn't specifically point to powderpost beetles without the context of the exit holes. Thus, the small "shot hole" exit openings are the most reliable sign of powderpost beetle infestation in wood surfaces.