Wood-boring Beetles Can Take Years to Appear

By Chris Williams on June 19, 2013.


Powder post beetle damaging wallsEither I’m going crazy or we have something boring inside the walls of our family room. I found a hole right through the wallboard and I swear I can hear something chewing behind there! Do you think this is just an isolated incident or could we be facing some serious wood damage? Our home is only 6 years old.


You could be dealing with wood-boring beetles. They are not uncommon in new homes. Usually, they have already infested the wood before construction and are built right into the home, emerging years later.

When beetle larvae have completed their development and have become adults inside of wood, they bore holes to the outside which are known as “exit holes.” These holes vary in size and shape according to the beetle involved. The infested wood may look fine on the surface. The real damage to the wood is discovered only if you pry into the wood or split it open. Then you will see many galleries of different diameters, running primarily with the grain of the wood.

The amount of damage that wood-boring beetles can cause in any given location will vary depending on many factors including the type of beetle, the type of wood (hardwood or softwood), the part of the wood involved (sapwood or heartwood), and the environmental conditions (temperature, humidity) at the infestation site.

Wood Moisture Levels Are Key for Ongoing Infestation

Water on wood damage Many wood-boring beetles require a high level of wood moisture for larval development. Newly constructed homes contain unseasoned wood and have a higher level of humidity. However, once beetles emerge in a new home years later, the home has usually dried sufficiently and they are not able to reproduce. Homes that have excess moisture in the basement or crawlspace, or those that are closed up and unoccupied for long periods are at greater risk of ongoing damage from wood borers since they can successfully reinfest the damper wood. Central heating and air conditioning in a home greatly decreases the amount of damage done since it dries out the wood framing and trim.

“Old House Borers” Are Really New House Borers

You need a professional to determine whether you are dealing with wood-boring beetles, and what kind. One possibility is the old house borer which usually emerges from infested wood 5 to 7 years after construction, leaving oval exit holes in the wood. The old house borer is a large beetle that, despite the name, is common in new construction. The amount of damage that the old house borer causes is usually limited, often only a few boards are infested. This beetle causes concern for homeowners because they can often hear the gnawing sounds of the large larvae inside the wood. The old house borer is capable of reinfesting wood in a home after it emerges. But if the home is heated, well ventilated and occupied, a second generation rarely occurs. Serious damage usually occurs only in unheated areas of the home or where there is a moisture problem.

You need to contact a pest management professional to evaluate your situation. A Colonial technician can inspect your home and determine what is causing the damage. We’ll tell you how extensive the infestation is and give you our recommendations for control.

Photo credit: Urban Combing (Ultrastar175g) / / CC BY-NC-SA



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