Last summer we had a lot of wasps and yellow jackets in our backyard. Our kids could not go outside for fear that they would get stung. A friend of mine told me that if you put meat or fish outside and put a bucket of water undreneath it then the wasps would eat until they could not fly anymore and they would fall into the water and dround. I was skeptical about this approach, but tried it anyways. Sure enough it worked. I tied a piece of meat on the top of a 5-gallon bucket and put approximately 5" inches of water in the bottom of the bucket. Sure enough it worked. The wasps drownded. Unfortunately it did not kill all of the wasps, so my friend suggested that I put shaving cream in the opening of the wasps nest at night while they are sleeping and they will sufficate. Both of these solved 98% of our wasps and yellow jacket problems.