Bees Under Deck

[Mugz]

I have some bees underneath my deck. I continuosly see them going through the cracks between the boards on the surface of the deck. The bees look similar to honey bees but not as big. I was thinking carpenter bees but I wouldn't think they would burrow into PT wood?
I cannot get underneath the deck...it is 8" off the ground with chicken wire all the way around (to keep out critters).
This weekend I took off one 16 ft length of wood....stuck a mirrow down there so I could look underneath in between each joyce bay....NOTHING. No hanging bees nest. So, I think they are in the ground....but I don't want to have to rip the whole deck up to get at it. I know the general vicinity they are in. Is there some sort of bomb, something I can put under the deck to get rid of them without knowing exactley where the nest is?
The bees don't seem to bother us on the deck, but a few people had visited my deck who were allergic to bees and kind of got freeked out.