What’s in your firewood? A guide to wood-infesting insects and pests
Firewood can host a variety of wood-infesting insects, which occasionally escape into the home when firewood is brought indoors. Most of these pests are only a nuisance and will not hurt people, nor damage furniture or the home. The moisture content in furniture and structural wood is generally too low to support insect infestation. Here’s a guide to what pests may be in your firewood.
Many species of wood-boring beetles infest firewood. Their immature (larval) stage is a creamy white segmented worm with a dark head, and is sometimes found in tunnels when wood is cut or split. Sawdust may be packed in the tunnels or may pile up around the firewood. If firewood is stored indoors for many weeks, the immature insects may continue their development, and in mid to late winter the adult beetles can emerge in the home.
Two wood borers commonly discovered indoors at this time of year are the red-headed ash borer and the banded ash borer. Both insects resemble wasps with their long legs and yellow horizontal stripes. They even buzz when they fly. Fortunately they do not harm people or pets and will not infest wood in the home. A swat with a rolled up newspaper will take care of them.
Another wood borer found in firewood is the notorious emerald ash borer. This half-inch long bright green beetle will not damage furniture or your home, but it is an aggressive killer of ash trees. Emerald ash borer has not been found in Nebraska, but could inadvertently be introduced in the state on firewood from any of the 25 states where it is known to occur. If you think you have found emerald ash borer in your firewood, contact the Nebraska Department of Agriculture or your local county extension educator or forester.
These big black or reddish ants typically nest in decayed wood and are often found in large old trees. Firewood stacked on the ground also may develop decay and subsequently attract carpenter ants. Although dormant in winter, ants nesting in firewood may become active when brought indoors.
Subterranean termites live below ground but feed on aboveground wood. They may infest firewood that is in contact with the soil. Termites retreat to their underground nest when temperatures drop so are unlikely to be carried into homes in winter via firewood. Firewood stacked against a home in summer, however, may become a conduit for termites to infest the home.
Other potential firewood residents include horntails, powderpost beetles, bark beetles and Lepidopteran borers, along with other various shelter-seeking insects such as wood roaches, pillbugs and spiders.
Management of firewood pests
To alleviate concerns, store firewood outside and bring in only what can be burned at one time. Do not treat firewood with insecticides, because toxic fumes may be released when the wood is burned. Most firewood insects are too deep in the wood to be affected by the insecticide anyway. Insects that have emerged indoors can be swatted or picked up with a vacuum.
Since many firewood pests are attracted to freshly cut wood, harvesting firewood in late autumn when few insects are active may help limit infestation. Keep the wood off of the ground and stack it loosely to improve air flow and speed drying. Do not stack against buildings or indoors.
Finally, use local sources of firewood to avoid the introduction of emerald ash borer and other invasive pests. ❖
Laurie Stepanek is a Nebraska Forest Service Forest Health Specialist. This column was printed courtesy of the Nebraska Statewide Arboretum at the University of Nebraska-Lincoln.
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