QuestionsHow to growVegetable GrowingPotatoesBlack patches on potato plant 0 Vote Up Vote Down Sheleen Johnston asked 15 years ago One of my early potato plants has black/brown bits on leaves, could this be blight? Its only one plant, the rest seem fine. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Impossible to tell from the photo, but it could be. Sometimes blight appears on one plant first. There have been Met Eireann blight warnings already. You can often tell blight by a white fungus on the leaf back.Â