Keep hunting for interior carpenter ant nests

Question: Judy, sometimes I can easily find a carpenter ant nest in a customer’s house, and other times I can’t. As a result, I’m just killing worker ants, which I know isn’t the way to solve the problem. I’m using baits when I can’t find the nest. Is there anything else I should do?

– Hunting Undetected Nesting Trails

Answer: Thanks for your question, HUNT. It really brings back some memories. Early in my career, about 80 percent of our services for residential customers started out as carpenter ant issues. Because I know the area from which you are writing, I’m going to focus on Camponotus pennsylvanicus. It most likely is the carpenter ant species with which you are dealing.

I’m going to have to assume that the nests you are talking about are in the house, and these carpenter ants are not entering from a nest located outside. Generally speaking, with interior nests, the frequency of sightings, number of ants sighted, and time of day (daytime) are big clues that the nest is inside.

Baits that are labeled for carpenter ants really are pretty good these days, so you are on the right track there. But your instincts are right that finding the nest is the quickest way to help your customer.

The biggest struggles I’ve had finding carpenter ant nests occurred when I focused too much on what is typical: Where are the current water leaks, and where are the old water leaks? Carpenter ants can, and do nest in dry void areas.

The first time I found ants in an interior hollow-core door, for example, I was shocked. I’d like to say my brilliant inspection skills found the nest, but actually I was just standing in the customer’s bedroom thinking, I have no idea where these carpenter ants are coming from, when I bumped the door against the doorstop and a couple of worker ants came out of the bottom corner of the door. Now I always check those doors, even if I don’t suspect them.

At that account, I had the customer help me gently take the door off its hinges. We brought the door outside, and I was able to treat the nest without risking ants running out of the nest and into the bedroom. Some did start to run out when the customer whacked on the hinge pins, but I put masking tape over what appeared to be the only opening on the door, and we got the door outside without ants pouring out.

Why weren’t the ants tunneling in soft wood and creating their own void space in which to nest? Well, finding a ready-made void space allowed the ants to create a nest with a lot less effort. I assume they were getting their moisture from their food sources or something on the exterior, as this house had no water leak issues that we ever found.

The final step was to try to figure out how they got into the house in the first place. At that account, caulking around the windows seemed to do the trick. Try expanding the type of area you are inspecting to find the nest, to include areas you might rule out because they are dry.