By Stephanie Hughes
OSU Ext. master gardener volunteer
Most people move firewood close or into their homes this time of the year. Along with that firewood, an invasion is not only possible, but probable. People cut firewood from dead, dying, and damaged trees, the ideal place for insects to move in and live. Though most do not pose a threat or damage, they’re annoying. Following guidelines for firewood, along with identification of the insects, goes a long way to head off this invasion.
The popular groups of insects are the wood-boring beetles, whose larvae are whitish, legless grubs. They favor ash, hickory and oak, but any tree can be threatened if conditions are right. The flat-headed borers can also infest the wood pile. Larva tunnels in wood are three times as wide as they are high. Bark beetles and ambrosia beetles also need to be considered. Sugar maple borer activity evidence is sawdust near the woodpile.
The emerald ash borer has invaded our region and is the cause of serious destruction. For this reason, no firewood should be transported or moved, and any emerald ash borer infestation should be reported to the extension office or Department of Natural Resources. The emergent tunnel hole is characteristically “D” shaped, and symptoms of infestation are dieback from the top of the tree down; vertical splits in bark; D-shaped exit holes 1/8-inch wide; S-shaped canals under the bark; heavy woodpecker activity, especially in winter; and new tree shoots at the base of the trunk.
Carpenter ants are attracted to wet, stacked firewood. These large black to reddish ants are 3/8 inch long. They move in with the wood, and come out as the logs dry out, and can be a serious problem in the home, as they migrate to wet, decaying wood in basements, garages or crawl spaces.
Termites infest wood with mud tunnels around the woodpile. They are dormant during winter. Wood can be treated with insecticides, but it is not advised. Termites will infest structural wood, and woodpiles stacked close or touching the home or garage should be inspected by a professional.
Miscellaneous shelter-seeker pests include spiders, other beetles, wood roaches, sowbugs, pillbugs, wasps, ants, small flies, and even queen hornets., and they may move into the home by way of firewood. Spider sacs, praying mantis egg cases and moth cocoons are associated with trees and fallen logs. They usually leave wood after being brought indoors, and the wood warms up.
Homeowners must realize that some nuisance insects are going to come in. When firewood warms up, out they come. Learning to recognize and identify common insects will aid the homeowner in dealing with these pests. Bring in firewood only as needed; don’t stack it against the home or garage; use the oldest wood first; cover the woodpile in summer and fall, shake logs to dislodge insects; don’t treat it with insecticides, and cut wood mid- to late fall when it is less attractive to borers.