Question

I was just doing some repairs in my shed and discovered some kind of insect galleries inside one of the joists. How do you tell the difference between termite and carpenter ant galleries in wood? I didn’t find any insects.

Answer

In an outdoor shed that probably has fairly high wood moisture, you could easily find either one of these wood-destroying insects. The best way to describe the difference in their galleries in wood is that carpenter ant galleries are neat and clean, while termite galleries are muddy and messy.

Carpenter ant galleries

Carpenter ants don’t eat the wood but just tunnel into it for a nest site. Their galleries are irregular excavations, often with rounded edges that are smooth and clean. The galleries feel like they’ve been finished off with fine sandpaper. Near the nest site, you may find piles of coarse sawdust and other debris which the ants push out of the galleries. Often these piles will contain the bodies of dead ants or the remains of other insects which the ants feed on.

Subterranean termite galleries

Termites do eat the wood that they tunnel in, so there will be no piles of sawdust or dead insects beneath termite galleries. You may find protective mud tubes leading to the infested wood. Subterranean termite galleries in wood are packed with “mud” (a combination of soil particles and fecal material). In cross-section, the damage seems to be layered since termites avoid the rings of harder, summer wood, eating the softer layers instead.

You might want to have a professional pest control company inspect your shed to identify the pest and determine whether the damage is confined to that one joist or whether other wood in the shed is also involved. Depending on which insect is doing the damage, control may only require replacing the wood or a simple surface treatment of the wood. Or, the damage may be old, requiring no control at all. Give Colonial a call today and get quick answers to your pest questions.

Photo credit: Webb Zahn / Foter.com / CC BY