"Stephen M. Henning" wrote in
news
If a leaf has brown areas with white spots, it probably has a
local fungal infection of Pestalotia leaf spot. This is seldom
controlled with fungicides and is best mitigated by good
sanitation and avoiding excessive moisture

I have 2 rhododendrons with very similar symptoms to what the
original poster described. I posted some pics here.

http://img19.photobucket.com/albums/v56/jjjggg/Sick Rhodie/ex1.jpg
http://img19.photobucket.com/albums/v56/jjjggg/Sick Rhodie/ex2.jpg
http://img19.photobucket.com/albums/v56/jjjggg/Sick Rhodie/ex3.jpg

There were three of these plants that were planted a year ago by the
landscaper. I lost one already last summer to root strangulation,
because the lanscaper did not losen the rootball. I fear I am about
to lose the other 2. These plants are north facing and I thought it
might be winter burn too, but as both shrubs growing profusely, so do
the brown spots. The other plant, not in these pics, looks the same.

Do you have any idea what's wrong with these plants and is it
terminal?

2 out of 3 English Spreading yews he planted look sickly too and show
no new growth, but that's another story.

Gary
Zone 6/7