Photo from Iowa State University Forestry Extension Website. 
Bacterial Leaf Scorch on Pin Oak
Photo by Jim Peter, The Plant & Pest Diagnostic Laboratory at Purdue University
Bacterial Scorch on Pin Oak
Photo by Jim Peter, The Plant & Pest Diagnostic Laboratory at Purdue University
Bacterial Leaf Scorch on Oak Photographer Edward L. Barnard, Florida Department of Agriculture and Consumer Services
Peony blotch on peony (Paeonia) Image from Missouri Botanical Garden, Kemper Center for Home Horticulture Web Site