We have a series of three small carpenter bee holes on the North side of my garage right under the roof. We had them treated before with some sort of dust but alas they seem to come back every year (I believe it is in their behavior to inhabit previously drilled nests). I have thought about hiring an exterminator and was told by one to suck them all out with a vacuum at dusk or in the wee hours of the morning (when the female is less likely to sting), spray them in the vacuum and spray their nest and then seal the holes with liquid nails or new painted wood and there will be nothing else to worry about.
A neighbor who used an exterminator for a similar job a while back was told that you need to get in the nest in the "gallery" and scrape the bee eggs out or make sure they are born and active outside of the nest otherwise they just borrow out if trapped and could borrow holes into the living space of your house or attic and make more of a mess.
Anybody have any ideas or experience?