The trap described below is easy to make & will catch yellow jackets by the 100's!
I get an empty 1 gallon milk jug.
Cut a 3-1/2 inch hole on each side. Make sure the holes are about 2 inches off the bottom.
Fill with about 1-1/2 inces water. Add ONE drop of liquid diswashing detergent. This breaks the waters surface tension.
Hang a pice of meat inside the carton. This can be some lunch meat, fried chicken, chicken bone, pice of steak, anything the wasps will "smell"
Hang on a tree, pole or building.
The wasps will fly in the hole onto the the meat. When they try & fly away they will not be smart enough to exit the hole, hit the side of the carton & drop into the water.
Give it a try & let me know how it goes. It's real fustrating to be outside, open a can of soda & have about 3 yellow jackets helping themselfs to your drink!