Long-Horned Beetles
Appearance:
Depending on the species, adult longhorned beetles range about 3/8 to 1 inch long and are usually oblong or elongate and somewhat cylindrical. The antennae are very long, usually exceeding the body length and the elytra (hardened front wings or wing covers) usually cover the abdomen.
Depending on the species, mature larvae range from 3/8 to 1 1/2 inch long and have an elongate, cylindrical body with an enlarged, rounded thorax. The larvae are white to ivory colored and are legless or have very short spine-like legs.
Habitat:
Female longhorned beetles lay their eggs in wood or bark crevices during the spring, summer, or early autumn. Eggs are laid singly or in small groups. Larvae hatch in a few days. After finding a suitable entry point, they feed near the surface at first where the protein is in greatest concentration. As they grow, they bore deeper into the wood. The larval stage may last from a few months to several years, being prolonged by a low nutritional value of the wood and any decrease in moisture such as caused by the wood being sawed into lumber. Pupation takes place in a cell near the wood surface. The time of adult emergence depends on the species and environmental conditions. Outside, they mate, lay eggs, and die. Indoors, the only 2 species that can re-infest dry, seasoned wood are the old house borer and the flat oak borer.
Most roundheaded borers require at least 2 years to complete their life cycles (adult to adult), The old house borer requires at least 3 years; the flat oak borer 1 to 2 years.
Log homes present special problems. This is because bark is often left on the logs, especially around knot-holes. The logs are often either green or air-dried at the time of construction; design flaws allow the logs to increase or retain a high wood moisture content. Most log homes are constructed in wooded areas, and the logs are often not rigorously maintained with preservative and sealer. This situation often allows for a series of species of roundheaded wood borer infestations, which can start before the trees are cut and progress through advanced stages of wood decay.
Diet:
All four stages of the life cycle damage the host trees.
Solutions:
What you can do: For adults emerging from firewood brought indoors, remove the firewood to the outside and bring it in just before burning. There is no threat of infestation except from the flat oak borer, which is uncommon in firewood. Rarely is fumigation justified except in cases of widespread infestation, incessant larval chewing noises, or peace of mind. For re-infesting species, such as the old house borer and sometimes the flat oak borer, fumigation is often the appropriate control measure.
For species that do not re-infest wood and occur in low numbers, the damage from emerging adults is not structural but cosmetic. The usual procedure is to fill the exit holes with appropriate wood dowels or wood filler compound and finish to match. Penetrated linoleum and floor tile will often require replacement and roofing usually requires patching.
Professional Solution:
Log homes often require fumigation but this should be done in conjunction with correction of the conducive moisture conditions and followed by proper maintenance procedures. It is usually desirable to make an appropriate application of boron-containing pesticide to reduce re-infestation and retard wood decay before the logs are sealed. All exit holes should be sealed after the boron application but before the sealer application.
