This might horrify some, but I've always just tracked the yellow jackets until you find their hole. Then plug the hole(s) in the early morning before they're up with a coke bottle full of gasoline, and leave it for a day or two. Simple, cheap, targeted, and effective.
(coke bottles have more of a tapered neck than most bottles and fit in the hole better.)
If you can't get a vehicle out to a fire ant mound that is out in the open sun, it can be treated similarly but knock the mound flat, a small amount of gasoline, cover with a piece of roofing felt or a black garbage bag weighted down with a few bricks, and let the sun send the fumes through the tunnels. Some people pour gas on the mound and light it, but they're just pyros wasting gas , imo.
I prefer using an engine to pump exhaust fumes through the nest when possible, though.