Easiest way to kill bees is to add some dish detergent (like liquid Dawn) to Mountain Dew or an equivalent sugar filled bright colored soda. Place in a large container near the nest, as the fuckers fly away they will not be able to resist and go in for a drink, at which time they will screw themselves. Toxic for them to drink and I believe they will coat themselves with it, and the dish detergent will coat their wings and not allow them to fly away. So they'll either drown or be poisoned to death. Win-Win.
Makes me wonder what would happen if you just hosed them down with such a mixture, it'd be pretty awesome.
This does work but the trouble with this idea is your going to attract more bee's to the sweet nector than you may have originally had.