QuestionsHow to growTrees and ShrubsPests and Diseasespyracantha 0 Vote Up Vote Down Mary O Mahony asked 15 years ago I have a pyrantha planted on a bank in a very open situation for a few years. Unfortunately it seems to have lost its leaves and is not thriving,any idea what the problem could be. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago This is probably pyracantha scab disease, which is like apple scab disease, and it svery common. You can either remove the bush or spray it three or four times in spring and early summer with a rose blackspot spray.