Unfortunately, late blight has been confirmed in Leesburg, VA by the Plant Disease Clinic in Blacksburg. Potato and tomato growers (especially in the northern part of the Commonwealth) should take precautionary actions and increase scouting. For more information on late blight please refer to the extension publication link about this potentially devastating disease. Please let us know if you have any more questions.
http://pubs.ext.vt.edu/ANR/ANR-6/ANR-6_pdf.pdf