I have a lilac bush which is about 45 years old. Was doing good except for this year. The leaves curled and turned black. I don't see any evidence of a borer. Can you help?
Were any lawn herbicides applied near by that may have drifted onto the lilac?
How has the water changed this year? Black leaves can be a symptom of too much water.
I've seen discharge from new copper gutters do it too.