Rhododendrons: sick rhodo brow leaves

i was hoping some one could help me ID this problem with my rhodo. i have attached photos of the problem. this started late last summer and has spread from one plant to the next. my gut feeling is that it is fumgal if so what type and is there any control????? please help

 

In the big picture, that looks like sun scald (or wind burn as I forget which is which) to me but It can lead to secondary fungus infection. Have any trees been trimed?

 

if you have lost plants (wind/sun usually isn't deadly) and there has been no change to the garden and you have never experienced leaf/wind burn ... check ramorum leaf blight for your area...