I live in NE Alabama and we too have carpenter bees! When I moved into my first house, the wooden fence had dozens and dozens of holes from them. I learned that if a bee hatches at X, they will always come back to that spot to lay more eggs. Fortunately, I had a tornado take that fence away - but of the pieces left that i took to the burn pile, the bees were trying to lay more eggs in those old broken pieces!
I'm a fan of malathion. I mix in a gallon sprayer that every time i see a small pile of saw dust, i shoot a stream of malathion in the hole. within about 5 mins., the egg layer will come out of the hole and i kill her. I've had them cruise my deck and I'd spray them with more malathion - sometimes i'd kill them, sometimes they'd fly away. i've even used expanding spray foam in the hole. the key is to get rid of as many that have laid or are trying to lay. Another thing i do is fill the holes with wood putty and put up those carpenter bee homes. they DO work.
A good place to check is "domyown.com" i buy poisons from them every year or so. where i live now, have a problem with brown cockroaches (not german) and i get chems from do my own, to eradicate them.
HTH