Cambistat ?
I bought a house last Oct. and of course the trees all looked the same (no leaves). The one in the back yard is a 72 inch in diameter green ash as best as I can determine from looking on the INTERNET. The tree was obviously injured in an ice storm we had a couple of years ago and had been cut back. I found a tag on the tree "TGR CAMBISTAT 2010". I went on line and found this site. I've tried calling several tree services to come and look at the tree. I have bores in the tree. I've put down Bayer systemic insecticide ground drench; I've inserted Medicap systemic insecticide around the base of the tree and about 6 feet up on the trunk; i inserted medicap fertilizer caps around the base of the tree; I've dug in 9 4 inch inground fertilizer stakes; I've sprayed the tree with spectracide insecticide several times. I don't want to loose this tree. Since the tree services all seem busy I've started cutting off dead limbs to reduce the insect population. I'm old able to get up so high so some of the dead limbs are beyond my reach.
From your knowledge and experience is this an uphill battle with low probability of success.