What causes black spots on sweet potatoes?
I just dug a wonderful harvest of large sweet potatoes. I hadn't planned to dig them just yet, but the deer have eaten nearly all the tops. They started eating the tops about 10 days ago, but I left the plants hoping they would recover. Well, the deer kept coming back and now I have to dig them. Its actually okay because the potatoes are quite large, smooth and brightly colored except for the few with dark spots. The spots are spread out on the surface, almost completely covering some of the potatoes. The spots are not indented, rotting or scaly. It looks almost like mildew. Could this have been caused by the deer because the tops of the plants were eaten? This is the first year I've grown sweet potatoes in this sandy, humus rich soil. Thanks!