Ash tree bug found
We have several Ash trees on the west side of our property. The center of one has died (although the outer branches still seem to be ok. Saturday we found several bug shell (skins, ??) stuck into the trunk of the trees. They were light brown, cacoon looking shells. What might these be? Would they be the cause of the one tree trunk dying? And how do we treat them so the other trees do not die?
Utah County Utah
I don't know what these insects are but the tree likely has lilac borers, almost all ashes do, and it's very hard to keep them out. You can't kill the borers that are in the tree now, but you may be able to keep new ones out. You have to spray insecticide on the trunk every year at least once early in the summer to keep them out.