Laurie Forbes wrote:

What are the best ways of controlling carpenter ants?

I found an ant spray that's supposed to be ultra bio friendly, uses
wintergreen as one of the main active ingredients. It's quite deadly to
ants, and when sprayed on a trail of ants, those ants not sprayed,
really react when they get near it. Much more so that with regular ant
sprays. If you can find their trail, might try spraying straight
wintergreen oil on them and see if they refuse to cross it.

Jon