Is that just a piece of bread?

OK thanks everyone - leave them be, or use the powder... What is that hanging in the trap?

If you might decide to go with the trap I mentioned, here are some pics. You put the attractant in the trap, they crawl up the inside cone, through the small hole in the top, can't get out, and die. You just hang it up, take it down when you have a bunch of dead ones in it, unscrew the bottom, & dump them in the trash or wherever and repeat until they are gone. No getting near the nest, touching it, disturbing it in any way. You just hang it in a convenient place away from the nest & empty it when it needs it. Easy peasy. I think I got mine from HD for $12 to $15.

http://forums.pelicanparts.com/uploa...1408509807.jpg
http://forums.pelicanparts.com/uploa...1408509843.jpg

Make your own traps: https://www.youtube.com/watch?v=xqMBiEqOI2I

I just got rid of a huge nest. Hundreds, if not thousands. I had the same problem with the spray and only one entrance. I just sprayed every evening into the hole at about dusk (then ran as they tended to swarm out) and there were less and less. Eventually, after about a week, all had died or left. It seemed like it was not working at first...but apparently it was just because there were so many.

Paper wasps, hornets and yellowjackets are highly aggressive insects that may or may not be better left alone. In late summer a yellowjacket colony can grow to 5000 or more insects and an unprepared encounter with these guys can be deadly. Identify which species you have so you know exactly what you are dealing with. If you must eradicate it, do it late at night in a full wasp suit. More info on recommended treatments can be found here:

Urban Entomology [Ebeling Chap. 9 part 2] Pests Attacking Man and His Pets

Years ago we had a large underground yellowjacket nest in our south 40 and the bugs were making it impossible to enjoy being poolside in August. A late night assault of 1qt kerosene down the hole was effective.