Insects and Other Pests Infesting Firewood
Answering Customer Questions - Safety First
Written by Techletter. Reprinted with permission. www.techletter.com.
You might be starting to get calls from customers who are suddenly finding insects inside their homes. If you're in a temperate region, those insects could be fall-invading insects becoming temporarily active, or they could be insects that have hitchhiked inside on firewood and are now making an appearance.
Often it takes a day or two after wood has been brought inside before the hitchhikers warm up and become active, although they're usually moving sluggishly. Before they emerge, firewood insects may push sawdust out of holes in the wood and can make faint noises in the wood, alarming customers. Many of the emerging insects will head to windows or lights.
What Kind of Pests are Found in Firewood?
The types of pests that can emerge from firewood depends on the wood's cute age (dried and seasoned, or not quite), condition (damp and decaying, bark on or off), and how it has been stored (on damp ground or up off the ground). Firewood pests are generally of two types:
- Pests that are actually living in and tunneling in the wood -- carpenter ants and termites are the most common, but also various wood-boring beetles and horntail wasps.
- Pests that are just overwintering or using the wood as a temporary shelter -- includes most of the occassional invaders or nuisance pests that can be found around a home's foundation and that require high moisture such as earwigs, centipedes, sowbugs, psocids, springtails, crickets, scorpions, ground beetles, and cockroaches, but also includes fall-invading and overwintering insects such as Asian lady beetles, stink bugs, plant bugs, and new queen wasps... and look out for black widow spiders that just love wood piles!
Answers to Customer Questions About Pests from Firewood
Q. Will they infest my house? This is probably the most common question when firewood pests end up inside. They rarely survive to become even short-term pests indoors because (1) they're usually brought inside in small numbers, (2) they're sluggish from their semi-hibernation and be easily captured, and (3) most have a hard time surviving in drier, indoor conditions with low wood moisture levels.
Q. Can I spray the wood with pesticide to kill the bugs? No. There are no pesticides registered for direct spraying of firewood. Never spray wood that is to be burned in a fireplace because of the risk of inhalation of potentially harmful fumes. Insects that are just sheltering in the wood will usually move on and larvae, ants, or termites that are tunneling inside the wood usually aren't reached by pesticide spray anyway.
There are a few pesticide products that allow outdoor treatment of the soil underneath firewood piles since some insects move into the wood by this route, but it makes more sense to simply stack your wood up off the ground. This keeps it drier too.
Q. Then what can I do? Because insects emerging from firewood indoors are sluggish and usually appear in slow numbers at random times, you can vacuum or sweep them up or us a fly swatter as they appear. It's possible that just a single piece of wood in your indoor stack is infested. Then just carry it outside and discard it some distance from the house. If for some reason, you have a large number of insects emerging, call a pest management professional. A professional can also treat your indoor firewood "holding area" (not the wood itself) with a residual insecticide that will kill pests as they emerge.
You can always keep your firewood outside, bringing in only the quantity you are going to use at the time. Removing the bark before bringing wood inside also eliminates many pests that hide just under the bark. Don't store extra firewood in a heated garage or basement or insects will emerge there, perhaps unseen.
Q. Can I still burn the wood? There is no reason that you can't burn insect-infested wood that is untreated, but wood that is infested by tunneling insects is probably wet and decaying and of little value in a fireplace anyway. Maybe it's time to invite friends for an outdoor bonfire instead, complete with marshmallows, to get rid of the wood and the ants or other insects at the same time.
Q. Is this going to happen nest year, too? Practicing proper firewood management can eliminate the problem of insect-infested firewood int eh future. Split and stack wood loosely and off the ground for drying. Wood that is properly seasoned will be too dry for most wood-boring insects to survive. Burn older wood first since wood stored for more than two seasons is likely to decay and become infested. Check firewood during the summer; discard any pieces that seem to be infested, rotate and re-stack the pile.
