Deathwatch beetles (Anobiids)

categories: Fact Sheet Wood Destroying Pests

revision date: 2025-12-15 03:05

Biology

Deathwatch beetles or anobiids are reddish to chocolate brown beetles ranging from 1/8 to 1/4 inch long. These beetles are rarely seen by people, but fresh piles of granular or gritty frass (insect excrement) on the outside of joists, mudsills, etc. are a sign of their presence.

The larval form spends 4-5 years feeding on wood before emerging, mating and laying eggs. Their preferred host woods are softwoods including Douglas fir, but some species may be found occasionally on hardwoods. Anobiids can be found in crawl spaces, basements, attics, and other structures with a moisture content of around 14-17%. They can hollow out pier posts, joists, studs and sill plates of homes. They are problematic when crawl spaces are not vented properly and when vapor barriers are either missing or fall into a state of disrepair. They can cause huge economic losses to buildings if not eradicated.

Management Options

Use Integrated Pest Management (IPM) for successful pest management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Infestations die out naturally. Determine if you have an active deathwatch beetle population by cleaning the area thoroughly and checking periodically for fresh accumulations of frass.
• Be sure foundation vents are clear and well-placed around the foundation to ensure good cross ventilation.
• Be certain an intact vapor barrier is in place. The soil beneath the home transpires water up into the substructure at a startling rate.
• If the infestation is localized, replace the infested lumber. Be sure to consult with a professional before doing lumber replacement.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• There are no pesticide recommendations for homeowner use against this pest.
• Consult a Pest Management Professional.