Answer: Unfortunately, based on your description I am not certain what has been happening to your lilac although it may be a scale infestation. Lilacs are subject to mildew infections but in my experience the mildew would not be like grains of rice, instead, it would seem powdery. I would suggest that next season, as soon as you see it beginning, consult with your county extension (696-3500) for a specific diagnosis and suggestions as to what to do. If it is scale, it needs to be treated because it can eventually kill the plant. Mildew on the other hand is unsightly but not lethal. I'm sorry I can't be more helpful.
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