Question
I have a white powder on the bark of one of my main lilac branches. It covers the bark about two feet high.  Is this a fungus, do I need to do something about it?  I live in New York and winter is coming.

Answer
Patricia,

What you have is most likely powdery mildew and lilacs are usually covered with it by fall.  It should not have any effectson your plant.  If you want to be sure take a sample to your local extension office for some diagnostics.

Good luck

Gary