Learn the habits of these wood-eating insects, and how to treat and prevent an infestation.

What Are Wood-Boring Beetles?

Wood-boring beetles serve an important role in nature, which is to break down wood so that it can be utilized by plants as food. There are many species of wood-boring beetles, but they all function the same way. They break down wood by laying eggs inside of cracks and holes in wood and then the larvae eat their way through the wood.

This makes them difficult to control because you don’t know you have an infestation until the damage is in progress, or done. We’ll show you how to identify the damage and ways to prevent or eliminate these destructive bugs from your home.

Wood-Boring Beetle Damage

Left uncontrolled, wood-boring beetles can compromise the structural integrity of furniture, furnishings, buildings, and homes. How can such tiny beetles do so much damage? Because unless you know the signs, you may never know they're present while they slowly eat away at wood for months and even years. It should be noted, though, that not all wood is attractive to wood-boring beetles, and different species will actually seek out different and very specific kinds of wood.

Keep an eye out for these two signs of a wood-boring beetle infestation so you can recognize and prevent them from damaging, or further damaging your home and property.

  1. Wood powder. As larvae eat their way through the wood, they’ll leave behind frass, which is a combination of wood powder and excrement. If you find fine, white-colored powder near wooden structures, then there’s a good chance you have an active infestation. If the powder is clumpy and yellow in color, then it could indicate an older infestation where the larvae may have matured and moved on to reproduce.
  2. Holes and tunnels. Whether it be wooden furniture, the framing of your home, a shed, or even a pile of firewood, finding exit holes and tunnels in wood can indicate an infestation. This means larvae have eaten through enough wood to mature and have left to lay eggs and continue their cycle of destruction. Exit holes can range from 1/8 to 1/2 inch in diameter depending on the species. It can be hard to determine if an infestation is active or not just by looking at the exit holes. It’s best to contact a pest control professional to determine the severity and treatment options.
  3. Stained or blistered wood. This can happen as a  result of the larvae tunneling below the surface.
  4. Clicking sounds. Some species of wood-boring beetles will create an audible ticking or clicking sound as they eat through wood.

How to Prevent Wood-Boring Beetles

Follow these tips to prevent wood-eating insects from infesting your house:

  • Keep firewood far away from your home and never store it against exterior walls. Make sure you only bring in firewood that you're ready to burn soon.
  • Since wood-eating insects prefer a little moisture in the wood they attack, make sure any lumber you buy is kiln-dried.
  • Check wood for exit holes before you take it home.
  • Sanding and varnishing or painting bare wood keeps adult beetles from finding a little crevice to dig into.

Wood-Boring Beetle Treatment

Every species of wood-boring beetle has the same life cycle: egg-larva-pupa-adult. The adults are harmless; the larvae do all the damage. Since the larvae are inside the wood when they eat, they can be difficult to control.

Products that contain borate are effective against wood-boring beetles because they penetrate wood, killing the larvae. They also linger to prevent another infestation. Ask your local hardware store where to find them.

Major Types of Wood-Boring Beetles

There are many different species of wood-boring beetles. Knowing which one you’re dealing with can be a good start to getting rid of them.

Powderpost beetles. These beetles are very small, only 1/8-1/4 inch long as adults, depending on the species. Their exit holes are round and range from 0.8-1.6 mm in diameter. Sometimes, the only way you can tell if you have them is by the small piles of sawdust, or frass, that they leave outside their holes. The dust/frass will contain no pellets and will fall easily out of the exit hole, unlike some of the other species listed below.

Old house borers. These beetles grow to 1/2 to 1 inch long and only attack softwoods, primarily pine. If you see larger holes, up to the size of a dime, this could indicate you have old house borers. Additionally, old house borer exit holes are typically oval with ragged edges.

Deathwatch beetles. These small beetles grow to about 1/8 inch long as adults. One way to identify this beetle is if you see holes in wood and hear a clicking sound coming from it.

Wood-boring beetles are not the only insects that can destroy wood and compromise the structural integrity of buildings and homes. Learn how to kill other wood-destroying insects by reading How to Identify and Control Termites and How to Get Rid of Carpenter Ants.

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