Its best to eradicate any infestation(wd-40 or an insecticide) and then plug the holes in the fall- don't plug until the larvae are dead, or the woodpeckers will come get them. Put the traps up in those locations. Carpenter bees always come back to the previous nesting site, so without the opening to the actual nest there, they go right into the traps. I have fought this for many years owning a log home, and this will give the best results. Still have to monitor for drilling in new locations, and place traps as needed.