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Firewood insects: An indoor pest or not?

Jeffrey Hahn, Extension Entomologist

It can be common for wood boring insects to emerge from firewood that is brought indoors. These insects can also come from other wood such as decorations made of branches or from new construction. Fortunately, these insects are harmless to people and property and do not reinfest any wood in a home.
A whitespotted sawyer, a type of long-horned beetle.
Photo credit: Unknown

There is a wide variety of borers, including long-horned beetles, metallic wood boring (buprestid) beetles, bark beetles, horntails, and wood wasps, that are attracted to dying and recently dead trees. Parasitic insects, like ichneumonid wasps that attack these borers, can also be found emerging from wood.

When the wood dries naturally (as opposed to kiln drying), these insects are able to survive inside the wood. When wood containing insects is brought indoors, the insects can be fooled into thinking it is spring as it warms up. The insects finish their development and emerge. It is common for these insects to be attracted to
An ichneumonid wasp, a type of parasitic wasp that can be
found emerging from firewood.  Photo credit: Unknown
windows because of the light.

Once the insects have emerged, there are few options. The easiest control is physical removal of the insects as they emerge. If insects are a problem because of firewood, consider leaving the wood outside until it is ready to be burned so the insects do not have time to emerge.

For more information, see the U of MN Extension publication Nuisance wood borers and seed insects in homes.
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