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Wood-Infesting Beetles

Beetles That Infest Wood

General Facts

Wood infesting beetles are significant pests of forests. Although most species infest forest trees, a few are important structure infesting pests which attack wood structures and wood products in and around homes. Targeting the nutrients contained within the wood, the larvae of wood infesting beetles can bore into and damage flooring, furniture, and structural supports.

Types of Wood Infesting Beetles in Canada

Wood infesting beetles in Canada include ambrosia beetles, long-horned beetles, wharf borers, metallic wood borers, true powderpost beetles, false powderpost beetles, and deathwatch beetles. Known to invade homes, these species are pests that can cause significant structural damage.

Appearance / Identification

The various species of wood boring beetles can be identified by the type of evidence and damage that their larvae leave behind. Metallic wood borers, for instance, leave behind long oval holes larger than 6 mm. After completing the larval stage of development, wood infesting beetles typically grow to be at least 5 cm in size as adults. While the pests display a wide range of colours and body shapes, every beetle possesses six legs, two antennae, and two pairs of wings. The outer wings, called elytra, are hard and protect the inner membranous wings. image of old house borers
Image of Old House Borers


Found throughout most of the world, wood infesting beetles characteristically inhabit forests, where they bore into the trees to access the nutrients. As a result, the pests often find their way indoors when people unknowingly bring infested lumber or firewood into the home. Each species usually displays a specific preference for either softwoods or hardwoods. Some species even prefer multiple types of wood.


As larvae, wood-boring beetles feed on the wood they infest. The wood contains the moisture and sugars that the growing beetles need in order to develop properly.

Life Cycle / Reproduction

The life cycle of wood infesting beetles takes anywhere from six months to a few years to complete, depending on the species and environmental conditions. Eggs are often laid in pores, cracks in wood, or just on the surface. The eggs hatch into larvae which eventually penetrate into wood by boring into it. They feed and develop within the wood. Following pupation, the fully grown beetles then make their way to the surface of the wood and emerge through tiny openings often known as exit holes to begin the cycle again.

Problems Caused by Wood Infesting Beetles

Larvae are the main perpetrators of damage caused by wood-boring beetles, as the developing life forms burrow into and weaken the structural integrity of wood. However, the adults of certain species also bore into wood to deposit eggs. Larvae sometimes take a few years to develop into adults and will remain in the wood for the entire period of time. As a result, people can unwittingly bring home infested wood from the store and not become aware of the problem for years. Furthermore, the beetles within the wood may then re-infest or seek new lumber around the home. If the pests target structural wood, the home may become unsafe.

Detection / Signs of Infestation

Tell-tale signs of a wood-boring beetle infestation include the sounds of burrowing and the appearance of exit holes in wood. Frass produced by the tunnelling of adult beetles is usually left behind near the exit holes and serves as another sign of infestation. However, detecting an infestation can be difficult for untrained individuals because the presence of exit holes and frass does not always indicate an active infestation of beetles. Furthermore, adult beetles are not usually present in infested wood.

Prevention Tips

Using seasoned lumber and inspecting the wood before beginning any building project is one way to prevent infestations. Applying polyurethane, varnish, or paint prevents wood infesting beetles from boring into timber, as well. De-barking firewood, storing the wood outside, and using it immediately when the need arises also helps keep the beetles at bay. In addition, ventilating attics and crawlspaces while maintaining consistency in the temperature of the areas keeps moisture levels low, which in turn prevents beetle larvae from growing and deters the insects from burrowing.

Control / Removal

For smaller pieces of infested wood that can fit in an oven, exposing the beetles to temperatures of about 50 degrees Celsius or more for at least 30 minutes will kill the pests. Similarly, placing affected wood in subzero temperatures for extended periods may also eliminate the infestation. Removing and replacing the affected wood may solve infestation problems, as well. However, the only way for untrained individuals to be sure of the severity and proper handling of the situation is by using the knowledge and services of an experienced pest control professional.