My experience controlling yellow jackets is always after they become a nuisance and traps have worked well for me but they are hard work when you have to maintain 30 or more traps on a property and even the frozen apple juice expense starts to mount. I have never had any success in capturing queens early in the season- they seem to avoid the traps no matter what the directions may say.
On a property like mine there is no way to locate all the nests or even a significant amount- they can be in the ground, in the trees, on structures and they can be large or small. When I see a nest I don't even worry about stings, I just get out the extendable pole of my pole-saw, fully extend it and attack the nest from a safe distance, prepared to run if I have to. I only get stung when I disturb the nests I don't see.
[NAFEX] yellow jacket control,
Alan Haigh, 07/19/2008