This is the only way.
Oh dear lord! Bees! - The Something Awful Forums
Seriously, put an opaque white 5-gallon bucket over the hole upside-down. They can see light so their instinct to dig another escape route doesn't kick in. By the time they figure out they're fucked, most of the hive is dying or dead of starvation. For the sake of neighbors and mailmen, I suggest writing "WARNING: WASPS" on it. If you find another exit, get another bucket.
If that doesn't work, get one of these