We have a carpenter bee kit that is our most popular product(s) for carpenter bee control. The kit comes with a dust and a hand duster to apply in the existing holes. The dust will kill any carpenter bees that are in the holes and will kill the larvae when they hatch. After a few days all of the adult carpenter bees that are in the holes will die. You can patch the holes at this point. The kit also comes with a liquid concentrate that you mix with water and apply using a Chapin Premier 2 Gallon Sprayer (#21220). You should treat all of the fascia boards or any surfaces that the carpenter bees seem to be going after. This will prevent any new holes. When a carpenter bee lands on the wood surface to make a new hole, it will pick up the product you sprayed on its body and die when it grooms itself. Carpenter bees are only around for a short time in the spring, and then again in the fall. You will have to apply both times of the year and then after 2 seasons there will not be any more larvae in the wood and the woodpecker activity should subside.
Here is a link to the carpenter bee kit: http://www.domyownpestcontrol.com/carpenter-bee-kit-with-cyonara-97-p-1051.html