Powdery Mildew can be found on just about every plant there is when the conditions are right for it to grow. The spores are around us all the time. Baking soda is one product often used to contol PM, although Potassium Bicarbonate appears to work better. I have alos used a 50/50 mixture of fat free milk and water to control PM.

Here is a link that might be useful: Powder Mildew Control

Thanks kimmsr! We are 4th generation farmers and STILL love to hear of new ways to use Baking Soda ... God's wonder drug never ceases to amaze me ( that and vinager ). But the question has been brought up that I had not explored ... since this "spotted malady" came on soooo early in the season AND in even thru the plants growth (and continued new shoots) that this may NOT be PM !?! Please ... any other possiblities that could cause such a disgusting foliage on what had been such a handsome specimen?
Thank you again!

Powdery Mildew looks kind of like someone lightly dusted a plant with flour, so if what you have does not look like that it may not be PM. While some people think PM is a late season problem it can occur anytime the temperature and humidity is right. I have seen if in early June on the rare occassion we have had temperatures in the upper 70's and low 80's here then.