We had a nest of the nasty little buggers alongside our driveway where the kids walk to the school bus. After many brave sorties by hubby and I with wasp bombs, powder, other insecticides, we came across a solution that worked!
There is an ingredient in tomato dusting powder that knocks them dead. They take the powder back to the nest and it seems very effective. We like a challenge and did it in daylight (how stupoid are we!!) and put a nice dusting at the entrance and voila! Dead nasties.