Eastern subterranean termites are not the only insect pests that damage structural woods within the state of Massachusetts. Most structural infestations that occur within old colonial era houses within the state are caused by either carpenter ants or powderpost beetles, both of which are native to Massachusetts. However, unlike termites, powderpost beetles are more discriminate about the types of structural woods that they attack. Also, many Massachusetts homeowners notice powderpost beetle damage only after an infestation has taken place, as it is not easy to discern between an active and inactive powderpost beetle infestation.

Powderpost beetle infestations are not always noticed while infestations are active because beetle larvae bore into wood located below the surface of lumber where they cannot be seen. Powderpost beetle larvae bore through structural lumber as they develop. The larvae feed on the starches in wood for sustenance before emerging from the wood as adults. Adults emerge by creating small round “shot holes” in the lumber that they had been infesting. Most powderpost beetle infestations are first noticed by locating these shot holes and surrounding sawdust that had been excavated by the larvae. Therefore, most infestations are noticed only after the beetles have abandoned compromised structural wood. Homeowners are more likely to notice powderpost beetle damage rather than the beetles themselves, as the adults are only active at night.

Powderpost beetles cannot attack wood that has been painted, varnished, stained or waxed, and they are unable to infest softwoods, like pine. Although powderpost beetle infestations can remain in structural woods for several generations, decreasing starch content in lumber normally causes the insects to abandon a site after around five years. Active infestations can be discerned by the fresh look of excavated sawdust near infested lumber, while inactive infestations will feature discolored sawdust that is clearly old. It is recommended that homeowners sweep up all sawdust found around a suspected infestation site before returning later to see if more sawdust has appeared. Doing this allows homeowners to easily differentiate between an active and inactive powderpost beetle infestation.

Have you ever found sawdust near structural wood within your attic, crawl space, cupboards or any other location within your home?