Powderpost beetles
Powderpost Beetles
Powderpost beetle-damaged wood does occur in the Lower Mainland mainly in older homes. Usually these homes are built from old growth Fir.
Visual damage by Powderpost beetles are small, round holes 1/6" to 1/8" in diameter. These are the exit holes of the adult beetles. Tunnels inside the wood are filled with fine powder like sawdust and the excrement of the beetle larvae. This powder may be coming out of the holes and form small piles under the holes. The adult beetles are normally not seen.
Adult beetles emerge from April to July, they lay their eggs in midsummer in cracks and holes in wood. Larvae hatching from the eggs tunnel into the wood and they feed inside the wood for about one year until they emerge.
_ Powderpost beetles will attack the wood beams under the structure, especially if there is an exposed dirt floor, with poor ventilation. Softwood with a high moisture content stored in areas out of direct sunlight can also be attacked. Structural damage to wood is caused by re infestation. Wood can be structurally damaged even if it looks normal except for some exit holes.
Prevention
Powderpost beetles require unventilated dark humid conditions. Keep all exposed wood in your crawl space dry. Cover dirt floors with a plastic or concrete vapor barrier. Ensure proper ventilation and drainage.
Control should be done by professional Pest Managers.
More information
Powderpost Beetles (Lyctidae spp.)
_ The term powder-post is often used for a number of different beetles, including Bostrichidae (false powderpost beetle) and Anobiid (deathwatch beetle). True powder-post Beetles are however members of the Lyctid genus. The name refers to the fine powdery dust formed by the juvenile larvae eating through wood.
_ The life cycle generally takes about one year, most of which is spent in the larval stage feeding within a wooden structure. These larvae are more commonly called woodworm. This larval stage can however last up to 10 years depending upon a number of factors; beetle species and air temperature along with the moisture content, age and type of wood infested. Adult beetles are rarely spotted and people may not realize that their house is infested until the adults emerge from the wood around
June.
_ Over 90 species have been described. The two Lyctid species most commonly found in the U.S. are L. brunneus and L. linearis.
Characteristics:
_
Lyctid adults are about 1/8 inch (3mm) in length and reddish brown in color. The body has an elongated and slightly flattened shape. The head is prominent including antennae with a 2-segmented terminal club. The larvae are white or cream colored, "C" shaped, with the 8th abdominal spiracle enlarged.
Habitat:
_ Lyctid powder-post beetles lay eggs in large pored hard wood, such as oak, walnut, ash, and hickory. Hardwoods with smaller pores, such as birch or maple, are rarely infested. Once hatched the larvae live and pupate within the wood. They tend to live in dry seasoned wood and are most likely to infest wood used for construction, including log homes, conventional homes and
furniture.
_The presence of tiny holes in wood with accompanying piles of fine powder is a sign of an infestation. The exit holes made by the emerging adult and are around 1/16 to 1/8 inch in diameter. Indoors, adult powder post beetles tend to accumulate around windows and lighted areas, looking for an appropriate mating ground.
Foraging and feeding:
_ The larvae or woodworm feed on the cellulose of the wood, creating channels through the wood where they have been. Lyctid powder post beetles prefer the sap of hardwoods such as ash, hickory, oak, walnut and cherry. This wood contains the right amount of starch, sugar and protein in the optimal moisture content (between 10 and 20 percent). The fine powder they produce is called frass. This is a combination of boring dust and fecal material, and is helpful in identifying the beetle causing the damage.
Distribution:
_ Lyctid powder-post beetles are found throughout the United States.
Implication:
_ Powder-post beetles can turn a wooden structure into a mass of powder. In high numbers they do significant damage to log homes, furniture, wood floors and structural timbers.
Management:
_ Powder-post beetles are resilient. Despite the fact that most wood today is milled, kiln dried and often treated, the egg and pupae stages of these insects
prevail.
_ When an infestation is noted immediate action is required to reduce further damage. A non-chemical management may be applied. Cracks and any other entrance points can be filled or sanded down, followed by a coat of paint, varnish or wax. This does not stop the damage done by the larvae already in the wood, but will discourage further egg laying. Lyctid powder-post beetles do not normally reinfest filled
wood.
_ In the case of severe infestation, the wood may need replacing. Where this is not possible chemical methods may be sought. Boracare is an effective insecticide, applied to unvarnished wood by brush or a hand held pump sprayer. It is particularly appropriate for extensive use in the case of log homes. Boracare will penetrate wood from 2 to 4 inches deep and is a permanent treatment unless exposed to constant water. This environment will eventually leach out the chemical. Boracare will also help in the prevention of carpenter ants, carpenter bees, termites, fungus and wood rot.
