whats on these vine maples?

[bigjayfromwa]

I was over at my parents place and my mom was complaining that some vine maples had this white film on them and it was spreading onto some of her other plants. The problem is the vine maples in question are on the golf course property and she isnt allowed to just remove them. If i can figure out what this is maybe i can treat them for her or possibly write a letter to the golf course explaining why they should be removed.
It looks to me as some type of fungi. Is it possible for this to be coming from some something the course put on the grounds, since it looks like it is spreading out from the veins? Any knowledge would be helpfull. I just drop trees, not much into this type of stuff. The maples are in the pacific northwest region.

 

[Elmore]

Looks like Powdery Mildew to me...if in doubt call the county extension office and have them send someone out to evaluate it and make a recommendation. Here is some info on the subject, from Auburn in the Heart of Dixie : http://www.aces.edu/pubs/docs/A/ANR-0407/