Question
I probably have more than 40 yews planted throughout my yard and noticed as I was fertilizing them a couple of weeks ago that the interior branches are laden with white powdery clumps. Is this some type of fungus or other disease?

Answer
John:
From your description, I suspect an insect- perhaps a type of scale insect. Try to snip off a few of the smaller twigs with these "cottony" things on it and carry it by your local garden center for a positive Id and recommendation. You can also carry to your local agricultural Extension office for an ID also. Best to get an ID first. This will save you some $ when purchasing an effective pesticide.

Regards
Steve