Wood boring beetles are insects that damage trees and wood products. The adult beetles lay eggs to overwinter in trees or wood. The larvae (caterpillar stage) feed on the newly formed wood under bark (sapwood) and water in the tree before emerging as adults. Some may tunnel into the center of trees (heartwood). They may be metallic colored.

Most wood borers do not harm healthy trees, but instead look for damaged or stressed trees. If not controlled, they can destroy entire forests. Different types of beetles may prefer certain types of trees over others.

Trees may exhibit damage that indicate a specific beetle. Some may leave different shaped and sized holes in wood, scars, or powder outside of infested trees.

The best way to limit damage from wood borers is to prevent infestation. Sometimes, trees are removed from infested areas to prevent further spread of the insects.

To protect trees:

• If found, identify beetles to learn the best control methods. Your local Cooperative Extension Service may be able to help with identification.
• Plant trees adapted to your area. Irrigate trees properly.
• Inspect trees, shrubs, lumber, and firewood for damage. Frass (powdery dust) may show you where to look for beetle damage.
• Prune trees properly. If adult beetles are active during pruning, it may worsen the situation.
• Old, declining trees and those with significant damage to the main trunk may need to be removed.
• Inspect firewood for signs of beetle damage. Moving infested firewood can infect new trees.

To protect indoor wood products:

• Inspect firewood for beetles before bringing it inside. If damage is present, consider only bringing in small amounts of firewood.
• Not all wood boring beetles can damage indoor wood. A few species, like powderpost beetles, can infest furniture and structural wood indoors.
• Do not spray infested firewood with pesticides. Once burned, the pesticide could become a health hazard.
• Infested structural wood may need to be replaced. Consider talking to a professional for advice.

If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email us at npic@ace.orst.edu.

Wood Boring Beetles

• Identify your pest. Contact your Cooperative Extension Service for additional control information.
• Plant trees adapted to your area.
• Inspect trees and wood for damage from beetles.
• Depending on the infestation, you may be able to prune damaged wood.
• If pruned improperly or while adult borers are active, infestations may worsen.
• Some infested trees may need to be removed. Ask an expert.
• Inspect firewood for infestation before moving or using.
• Do not move infested firewood.
• If you choose to use a pesticide, read the label before you buy. Try a lower toxicity product first. Do not apply pesticides to firewood.
• If you have a pesticide product in mind, have your label handy and click here for information about that product.

County Extension Offices

Through its county agents, the Cooperative Extension Service gives individuals access to the resources at land-grant universities across the nation. These universities are centers for research in many subjects, including entomology (the study of insects) and agriculture. Each county within the United States has an Extension office, which is staffed with agents who work closely with university-based Extension specialists to deliver answers to your questions about gardening, agriculture, and pest control. You can find the phone number for your local county extension office in the local government section (often marked with blue pages) of your telephone directory or by clicking on the map below.

Additional Resources:

• Wood-Boring Beetles in Homes - University of California
• Wood-Boring Beetles - University of Missouri
• Powderpost Beetles and Other Wood-Infesting Insects - University of Florida
• Wood Boring Beetles - New Mexico State University
• Emerald Ash Borer - Iowa State University
• How to Handle Emerald Ash Borer (video series) - Iowa State University
• Bronze birch borer - Oregon State University
• Bronze birch borer and twolined chestnut borer - University of Minnesota
• Two-Lined Chestnut Borer - University of Wisconsin-Madison
• Woodborer, Metallic Woodboring Beetle - Texas A&M University