Garden Pests and Diseases: Boxwood in trouble, 1 by betulo

betulo wrote:
I bought and planted a couple of boxwood shrubs in pots last fall, and kept them at entrance to the house. It is not especially sunny because of nearby trees, but both shrubs had been doing pretty well. In fact, they even survived some relentless digging on the part of the squirrels (?), which ended when I placed chicken wire around the base of the stem.

However, the shrub on the picture started to show brownish discoloration a couple of weeks ago, and it is progressing.

What could be the reason for it?