Firewood Beetles Flare-Up

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This is the time of the year when we get reports of painted hickory borers (Megacyllene caryae) and banded ash borers (Neoclytus caprea) emerging from firewood stored in or around homes.  Both are longhorned beetles (family Cerambycidae); so named because of their unusually long antennae. 

Neither of these native beetles presents a risk to wood furniture, flooring, paneling, or other processed wood in homes, or wood used in home construction.  They are just nuisance pests if they find their way into homes.  However, their sudden appearance can be a surprise and cause concern; particularly inside log homes.


Banded Ash Borer


Painted hickory borers will only infest dead trees that died within one year or raw wood (e.g. firewood) that has been cut for less than one year.  They target a wide range of hardwoods including their namesake host as well as ash, black locust, hackberry, honeylocust, oak, Osage orange, walnut, butternut, and occasionally maple.


Banded ash borers will only infest trees that are dying or recently dead.  They have a narrower host range including ash, hickory, elm, and occasionally, white oak.  Note that both of these native beetles infest ash which means they no doubt appreciate the plundering of ash by the non-native emerald ash borer (Agrilus planipennis).


Both beetles are considered forest products pests because they may infest fresh-cut logs used for lumber or firewood.  However, they also play an important role in forest ecosystems.  Both serve in the "clean-up crew" by starting the biodegradation process to convert large wood fibers into smaller organic particles that ultimately support soil microorganisms important to soil health.


Painted Hickory Borer and Locust Borer


On a final note, this is also the time of year when we get incorrect reports that locust borers (M. robiniae) are emerging from firewood in and around homes.  This is another longhorned beetle that is closely related to the painted hickory borer and both beetles share similar markings.  It is common for homeowners who are relying on online identification resources to make an incorrect ID.  However, painted hickory borers emerge in the spring and locust borers emerge in late summer to early fall at about the same time common goldenrod (Solidago canadensis) is in full bloom.  In fact, locust borer adults are most easily spotted on goldenrod partaking of the pollen and nectar.