Sooty blotch is a fungal disease that shows up in the damp shaded areas of the canopy.
Orange rust most commonly appears on the underside of leaves, but can infect canes as well. This disease can stunt plants and reduce fruit set.
Orange felt, also known as orange cane blotch, is caused by a parasitic algae Cephaleurons virescens. Orange felt occurs on blackberry floricanes in extremely wet, hot, and humid climates common in coastal areas of the southeastern United States. Canes have orange blotches and leaves can be white if the infection is severe.
Antracnose appears in spring on primocanes as small purple spots, later in the season they become gray in the center with purple margins. In this first picture they are yellow areas on the leaves and browned areas on the canes.
Cane canker caused by Botryoasphaeria dothidea is most often found on thornless blackberry cultivars
Spur blight start as infections on the leaf margin, move inward, and eventually through the petiole to the node. Infected leaves shed prematurely.
Cane reddening (go to virus section)