Answer: This might well be powdery mildew, although it is very early in the year to be seeing it. Generally it happens later in the season so the usual recommendation is to do nothing since it will not usually harm the plant. Since it is so early in the season though, you might want to control it. I would suggest you consult with your local county extension to obtain a definite diagnosis and based on knowing that, determine how to proceed. They will be able to recommend specific control measures if it is in fact powdery mildew -- or something else. Good luck with your lilac.
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