Will Lilac Blight Come Back Next Spring?

[TravisJN]

We have 4 mature lilacs and the leaves have black spots which seem to indicate blight. It is late October in Colorado so we're not too concerned about the rest of this year, but absolutely want the bushes to survive long term.

My wife thinks we should prune all the affected branches (about 50% of them) right now. I'm thinking we just let it go over the winter and see how things come back next year.

So my question: Is there a chance the blight will disappear over the winter and healthy leaves come back? Or is our best bet to hack out everything now?

Thank you.

[rainbowgardener]

I have a huge old lilac which every year gets powdery mildew and usually by the end of season some other kind of fungus which leads to curling leaves with black edges. I don't prune it or do anything about it. Next year it comes back just fine with fresh new leaves. I think for an established lilac, it's mainly a cosmetic issue.