Unfortunately your time to treat was last year and the year before, not this year...
Unless things have changed the only reliable treatments are preventative, and you waited too long. Your Ash tree is already dead, it just doesn't know it yet.
FWIW, my dad has had good luck treating 5 Ash trees at his house. They provide southern/western shade to the house and he didn't want to lost them. He has been treating every year for 10 years now and they are still alive despite the fact that EAB made it's roaring debut in his area about 8-9 years ago. In his area 99% of Ash trees are not only dead but have now been dead long enough most have fallen to the ground from rot.