If the nest is in a place where you can aviod it untill winter do it. You might not have any idea just how poisonous these sprays are. Give me a minute and I'll post some ideas for you from Organic Gardening.
This first one is concerning wasps.
http://www.ehow.com/how_5873463_rid-...e-poisons.html
Here is one idea! This one is for yellow jackets. A vaccum and Ice! This is from You bet your Garden.
Q. I’m fairly certain I have a yellow jacket colony next to a tree in my front yard. I was mowing, ran over a hole and got stung twice. I’ve heard you recommend getting a professional exterminator to handle this situation. Is there a firm you would recommend?
---Gary in Northern Virginia
A. Yes, Gary; ANY firm that will vacuum them out of the ground. Toxic insecticides are useless in this situation, as the massive underground nests of these hornets are of a design that sheds liquids off to the sides. (Which explains why they don’t all just drown in the first heavy rain.) So reject any firm that wants to come and spray; there’s a good chance the insecticide they’d use would harm you more than the wasps. If you can’t find an exterminator willing to use a high-powered vacuum, contact your local beekeeping society. Some beekeepers have this kind of equipment handy for sucking escaped feral colonies out of the house walls they occasionally occupy.
And if you’re careful (promise me you’ll be careful!), you can even do it yourself. Drop the hose of a shop vac or an old canister-type vacuum cleaner next to the hole in the middle of the night when the guards will either be deep inside or slow to react. (The cooler the air temperature, the more wiggle room you’ll have.) Then turn the machine on the next morning; these aggressive wasps will attack the hose and get sucked inside. Let the machine run all day—remember, you might need to suck up thousands of the stingers before you empty out the nest. Then plug the vacuum hose with duct tape BEFORE you turn the machine off. Then let the machine sit in the sun for a few days before you open it to dispose of the used-to-be-wasps.
But plug the hole to the nest right after you turn off the machine if you can; the queen will still be down in there, giving birth to new workers every day. You’ll find details on how to do this safely in this previous Question of the Week. This ‘ice and tarp trick’ also works well all by its lonesome when the hole leading to the nest is in an open area; I’ve used it successfully several times
But I had nothing near a clear shot at an open area when a late summer nest became apparent near my front door last month. The main entrance was hidden somewhere deep in the middle of a big planting of massive old ferns, AND the wasps had established a ‘side door’ in the opening where a pair of ancient landscape timbers meet. Clearly, this was a ‘sucky’ job.
Luckily, I have an old beat-up canister vac that I keep around for just such a purpose. It took a few days of repeated vacuuming for a couple hours a day, but I got rid of the entire nest without being stung once. OK—I was stung once; but that was my fault and not related to my sucking up the suckers. It happened when one landed in my hair while I was working in the garden and I brushed it away without thinking.
If you use a canister vac, start with a clean bag to insure the best suction. And then make sure you keep the machine turned ON when you open it up to seal the bag shut for disposal, no matter how long you’ve had it sitting in the sun. These creatures can be relentless, and you need to use every caution possible.
peace