Which of the following is an indication that wood is infested with powderpost beetles?

The presence of frass, which is the powdery wood dust that results from powderpost beetle infestations, is a key indicator that wood is affected. This fine dust is produced as the beetles tunnel through the wood to develop their larvae. It is often found at exit holes in the wood where adult beetles have emerged, providing visible evidence of their presence and activity.

The other indicators, such as a soft and crumbly texture, cracked surfaces, and unusual odors, can relate to various forms of wood damage or decay but are not specifically indicative of powderpost beetles. Soft and crumbly texture may suggest fungal rot, cracked surfaces can result from environmental factors, and unusual odors might stem from other wood-destroying organisms or moisture issues. However, frass is a definitive sign uniquely tied to the activity of powderpost beetles, making it the most accurate indicator of their infestation.