Old house borer
Hylotrupes bajulus
- Identification
- A longhorned beetle whose larvae tunnel in softwood framing; audible rasping chewing and oval exit holes are signs.
- Lifecycle & behavior
- Larvae develop in seasoned softwood for years, sometimes audibly, before emerging as adults.
- When it's active in Central NY
- Encountered in CNY softwood framing and can persist in a home's structural lumber; activity is sometimes heard before it's seen.
- Risk & damage
- Damages structural softwood over long periods; a wood-destroying insect noted in inspections.
- Why DIY falls short
- Deep larval galleries put the pest out of reach of surface products, and diagnosis requires experience.
- How we treat it
- Professional assessment, appropriate treatment of affected framing, and inclusion in WDI reporting.
Old house borer or powderpost beetle?
Old house borer exit holes are large and oval — roughly a quarter to three eighths of an inch — while powderpost beetle holes are small and round. The frass is coarse and gritty rather than flour-fine. Old house borers attack softwood framing; powderpost beetles attack hardwoods.
There is one further sign unique to this insect: in a quiet room you can sometimes hear the larvae rasping inside the wood, a faint ticking or scraping. It is unnerving and it is a genuine diagnostic.
Old house borers in Central New York
Despite the name, old house borers are most often found in relatively new softwood construction — the larvae can develop for years inside framing lumber, so an infestation frequently originates in wood that was already infested when the house was built.
They attack seasoned softwood structural members, particularly in warm areas like attics and framing near heat. Because the larval stage is long, damage accumulates slowly but can become structurally significant in the framing members affected.
Dealing with old house borer?
Our wdi / real estate pest inspection handles it — guaranteed, family-owned, and local.
Old house borer — common questions
I can hear a faint rasping in the wall. Is that insects?
Possibly old house borer larvae, which can be audible as a faint ticking or scraping as they feed inside softwood framing. It is one of the few wood-destroying insects you can actually hear. Worth an inspection to confirm rather than guess.