Round-Headed Borers (Old House Borers; Family Cerambycidae)
Round-headed borers are the larvae of beetles in the family Cerambycidae, often known as the “Longhorn Beetles.” Identification of the species in the larval form can be challenging (see this beautiful photo from a recent study in Scientific Reports). While these species are typically not a problem in homes, there is potential for an infestation to occur with unfinished wood at the right level of moisture, especially in log cabins and vacation homes.
Identification
Larva have slightly flattened elongate bodies, with hardened mouthparts, with very small legs (called prolegs). This factsheet by University of Missouri extension provides an excellent family-level identification guide to common wood-boring beetles that can be found in wood used for construction. More detailed click-through keys can be found on this webpage.
Huge larva of a round-headed borer species.
Pupal chambers in windthrown longleaf.
Click on image to view full-size
Control Information
Factsheets
- Sawyer Beetles – University of Maine Cooperative Extension
- Wood-Boring Beetles Damaging Construction Wood (PDF) – University of Missouri Extension
- Longhorned beetles – University of California IPM
- Roundheaded Borers and Longhorned Beetles – Iowa State University
Dig Deeper – Scientific Studies
- Identification of wood-boring beetles (Cerambycidae and Buprestidae) intercepted in trade-associated solid wood packaging material using DNA barcoding and morphology – Scientific Reports, 2017. Summary: It is challenging to identify the larvae of these species by looking at the morphology alone. DNA barcodes were used to identify beetles to genus or species to aid in investigations at US ports of entry.
[Photo Credit: William M. Ciesla, Forest Health Management International, Bugwood.org; Eugene E. Nelson, Bugwood.org; Timothy Haley, USDA Forest Service, Bugwood.org]