When I first heard about this, we were planning for an outdoor wedding reception for our daughter. Wasp always seem to appear where there is food and drink. A friend of ours told us how she dealt with wasp. We tried it and it worked so effectively that we had no trouble with the wasp.
All you need is a small fish, bucket, water, stick, string and some liquid dish soap.
Fill the bucket about half full of water and add a bit of liquid dish soap. Next place a stick across the top of the bucket and suspend the fish above
the water in the center of the pail. Place the bucket and fish in a spot that is out of the way. The wasps are such "pigs" that they will gorge themselves until they can't fly and will drop into the water-soap solution and drown. END OF WASPS.
Later, after the reception was over I checked the bucket and found dozens and dozens of dead wasps in the pail. All the wasps had gone to the fish and had not bothered us; the reception went very well.