There are a variety of insects that are attracted to dying and recently dead trees. If wood dries normally, these insects often survive, even if the wood is cut up for firewood or processed into lumber (assuming they weren't in the direct path of the saw). These insects then can be found in homes where firewood or lumber used in remodeling or construction projects are brought indoors.
A type of insect, associated with such wood, that people occasionally find inside is the wood wasp, family Xiphydriidae (pronounced zeye-phi-DREE-i-dee). This group belong to the order Hymenoptera which includes the wasps, bees, ants.
A wood wasp has a cylindrical body measuring between about 1/2 inch to almost 3/4 inch in length. It has a round, distinct head with moderate length antennae, often with a noticeable neck between the head and the thorax. The tip of the abdomen possesses a conspicuous ovipositor. Wood wasps are generally dark-colored but can also have white, yellow, or red markings.
There are 8 species of wood wasps that are common in the eastern U.S. of which at least three or four are found in Minnesota. Wood wasps are attracted to hardwood trees with decaying wood, although sometimes they attack trees that are generally sound. In Minnesota, common trees infested by wood wasps include birch, maple, elm, oak, hawthorn, and basswood. The most common wood wasp people find in Minnesota is Xiphydria mellipes (no common name). This wood wasp is about 1/2 - 5/8 inch long with a black body, white markings on the head and abdomen, and red legs. This species attacks birch.
Despite the size of this insect and its sudden appearance, it is harmless to people and property. Although it has an ovipositor, it does not sting. A wood wasp also will not attack any wood or wood products, like furniture, that is in the house -- it would only be interested in a hardwood tree, like birch, with the bark still intact. Wood wasps are short-lived once they are active and you would rarely see more than a few individuals at a time.
If the source of the problem is firewood, you can avoid problems with this insect (and other wood boring insects) by only bringing in as much wood as you plan to burn. Any unused firewood left in the warmth of the home could allow insects inside the wood to become active and emerge. If the wood wasps are in lumber, there isn't much you can do to prevent them from emerging. You can replace infested wood although it would be unusual for it to be severely infested. Otherwise just allow the insects to run their course. They will eventually go away on their own in a fairly a short time.
If you do encounter wood wasps, the only necessary control is physical removal. As they are short-lived and do not reinfest wood, insecticides are not needed or necessary for this minor problem.University of Minnesota Extension Service
