Powder Post Beetle Infestations
Facts About Wood Destroying InsectsPowder post beetles can infest any item made of wood. Most of the critters I hear about when helping home buyers find a home are the type that like wood with a high moisture content, but there are beetles that prefer to live in dry wood.
What do powder post beetles look like?
Adults beetles are dark brown to black, and only 1/8" to 1/4" long.
How did they get in the wood in my house?
Unsealed wood can harbor beetle larvae, so adults might not emerge until long after your home has been constructed. It could even take several years, depending on the species and individual conditions.
The heat from kiln-drying kills all stages of powder post beetles, and although dried wood is not as attractive to them, the process is not a cure for reinfestation.
How do beetles damage wood?
Adults beetles lay eggs in the crevices of uncoated wood. When larvae hatch, they start tunneling. Sometimes you can see the outline of tunnels near the wood's surface, following the soft areas of the grain, but in many cases you can't see any evidence at all that larvae are present.
As the larvae bore, the tunnels behind them becomes packed with sawdust. They stop near the surface of the wood, where they mature.
Adults break through the surface, leaving tiny round holes where they emerge. Sawdust spills from the hole, and can continue to spill out for some time even though an infestation is over.
How can I get rid of powder post beetles?
There are several chemicals that can be used, but they will not penetrate sealed wood. A more extreme (and expensive) measure is to tent the house and use poison gas to eradicate the beetles.
Ask a professional for advice about your specific situation. In some cases you'll find it's nothing to be overly concerned about. The inspector will tell you to simply watch for further development.
Ways to help prevent an infestation.
- If your house sits on a crawl space, or has a dirt basement, cover the earth with plastic to reduce moisture. Watch the surface of the plastic for sawdust falling from floor joists above.
- Inspect the floor or moldings beneath interior wood walls. Little piles of sawdust indicate beetles have been in the wood, but are not necessarily a sign of active infestation.
- Schedule yearly inspections with a qualified inspector.
If you're buying a home, look closely at wood beams and other structural components for beetle exit holes and sawdust. If you find traces of a beetle infestation, have the home inspected by a pest professional
If the infestation appears to have been severe, you should have an engineer or general contractor inspect the structural integrity of the home.