Old House Borers | Pest ID Guide
Quick Facts About Old House Borers
Old house borers are destructive wood-boring beetles that can cause extensive damage to wooden structures in Tennessee homes. Despite their name, these pests commonly infest newer homes when eggs laid in lumber are unknowingly brought into the property during construction.- Size: 20 to 25 millimeters in length
- Color: Brownish-yellow bodies
- Shape: Elongated body with large mandibles
- Active Season: Year-round, with swarmers most active in summer and fall
- Lifespan: Several years for queens and kings
- Reproduction Rate: Queens can lay thousands of eggs during their lifetime
What Do Old House Borers Look Like?
Old house borers have a distinctive appearance that sets them apart from other wood-boring insects. Their shiny black bodies measure between 20-25 millimeters in length and are covered with a fine layer of white hair. As members of the long-horned beetle family, they feature notably long, black, segmented antennae that can be as long as or longer than their bodies. The wing covers (elytra) are hard and black, protecting their wings underneath.Key Identifying Features
- Long, segmented antennae that are often as long as the beetle’s body
- Black, shiny bodies covered with fine white hair
- Two raised, shiny knobs on the pronotum (section behind the head)
- Distinct exit holes in wood that are oval-shaped, approximately 6-10mm in diameter
- Larvae are cream-colored grubs with powerful jaws for chewing through wood
Related Species
Old house borers (Hylotrupes bajulus) are often confused with powderpost beetles, which are smaller in size (3-6mm) and create much finer, powder-like frass. While both are wood-boring beetles that damage structural wood, old house borers prefer softwoods like pine, while powderpost beetles typically attack hardwoods. Unlike termites, which eat wood for cellulose, old house borers consume the starch and nutrients in the wood.
Property Risks
Old house borers can cause significant structural damage to homes and businesses by weakening wooden structures over time.
- Extensive tunneling through structural wood, weakening support beams
- Reduction in the structural integrity of wooden components
- Creation of exit holes that damage the appearance of exposed wood
- Long-term infestations can lead to costly repairs or replacement of wooden structures
Where to Look for Old House Borers in Your Home
Old house borers primarily infest the softwood used in construction, such as pine. Look for signs in exposed wooden beams, attics, crawl spaces, and unfinished basements. Evidence of infestation includes oval-shaped exit holes, fine sawdust-like frass near wooden surfaces, and a distinctive creaking or ticking sound made by larvae as they feed inside the wood.When to Call Professional Help
Professional intervention is necessary if you spot adult old house borers in your home or discover exit holes in wooden structures. Since these pests develop inside the wood for years before emerging as adults, seeing beetles indicates an established infestation. DIY treatments typically can’t reach the larvae deep inside wooden structures. If you hear crackling sounds coming from wooden beams or notice frass collecting near wooden surfaces, these are warning signs that require immediate professional assessment.
