We have lilacs out back and they seem to have something on them. It appears that they have been sprayed with something, but they have not. There is a whitish film on the leaves and the stalks of the largest lilac has some green “dry looking moss.” Is there something wrong with them? What can we do about it?
Lilacs are prone to powdery mildew in hot, dry weather. If this is what is going on, it will not harm the plant's health; it just looks unsightly. The dry moss symptom has me stumpted; a picture is worth a thousand words!