PP264, a 2-page ID sheet by M.M. Dewdney, J.D. Yates, M.E. Rogers, and T.M. Spann, provides images for identification and comparison chart for Citrus Variegated Chlorosis (CVC), Leprosis, Citrus Black Spot, Sweet Orange Scab (SOS) and Citrus Tristeza Stem-Pitting (CTV-SP). Published by the UF Department of Plant Pathology, May 2009.
http://edis.ifas.ufl.edu/PP264