This looks like damage done by boxwood spider mites. Hold a piece of white paper under a branch and tap the branch firmly. If spots appear on the paper and move around, it's likely that you have the mites. I suggest that you take a sample to your local Cooperative Extension office for confirmation and recommendations for treatment. You can find your Extension office at the link below. This is a free service. The publication at this link gives information on spider mites. http://pubs.ext.vt.edu/444/444-221/444-221_pdf.pdf

Sandy

Here is a link that might be useful: Virginia Tech Extension offices