Last year I used onslaught and cat food for yellow jackets. That is what O.S.U. recomends. This year a friend across the river told me to use fipronil . It's the active ingredient in frontline dog flea medicine . So far I fed two cans of cat food in a cage, laced with 5 drops of fipronil and I have no yellow jackets for the first time ever. I usually loose at least three hives every year to yellow jackets so you can bet I've tried every kind of trap out there.