I have in the past had a terrible time around the pool area with Carpenter bees. They are not quite as bad this year, but still have my share. What I do is "declare war on them." I arm myself with a long handled fly swatter and several cheap cans of Hornet spray and a comfortable lawn chair. When they fly into the hole I spray them, if they land near the hole I swat them! Only thing I can tell you if you swat them, when they land step on them. In the past they have laid on the ground a good fifteen minutes and then caught a second wind and took off again. Have also found if you can get them to land you can spray with the water hose and that will kill them also. Believe it or not it doesn't take all that long and you and in control again. Good Luck!