We have had great results with placing fermones in a bottle and hanging it in a strategic area, they go in and can't get out. These kits are sold at big box stores.
I definitely have to do this several times from spring, summer, and especially fall. We have so many aggressive yellow jackets that we can't eat on the back deck. They also give my honeybees heck. They attack constantly. I usually let nature balance itself out, but these yellow jackets are so vicious around here I have to intervene.
