Question
My friend has a seven sisters plant that she has had growing for atleast 3 years. It has done fine in the past but this year a good bit of the leaves are turning white, mostly on the top, but on the bottom as well. It almost looks like someone threw a hand full of chalk dust in the air over them, I was told that if the white were just on the bottom it might be a mite problem but that doesnt apply here, any solutions?

Answer
Powdery mildew looks like a coating of fine white chalk. White to gray growth, often powdery, on the leaves, shoots and buds. It can occur anywhere on the rose bush. Where normally fungal disease like damp or wet areas this one can cause problems even when it is warm. Powdery mildew spreads as wind blown spores. If possible I would use a fungicide spray on it to get rid of it quickly. However you can also try a home made spray.
1 heaping tablespoon baking soda
1 tablespoon Canola cooking oil
1/2 teaspoon of liquid dishwahing soap
Mix in  gallon of water

Here is more information for you.
http://plantclinic.cornell.edu/FactSheets/powdery/powdery.htm