You can make a homemade wasp trap using a bucket of soapy water, some string, a stick and a small piece of fruit. Tie the string around the fruit and then tie the other end to the center of the stick. Place the stick across the bucket from one side to the other so that the fruit hangs a few inches the surface of the soapy water. Wasps will be attracted to the fruit, land on it and as they try to fly away they will fall into the water. Place this in the area where the wasps are a problem. Empty the bucket every so often.
Let me know how it works. Take pictures and post them if you can so other people can see.