Get better Fruit Tree Fungus Treatment from Black Knot Be Gone and safely promotes healing of the whole tree for Black Knot disease contains all organic plant ingredients. You can apply our black knot be gone fungus spray, any time the tree is absorbing nutrients up through the root system, early spring to late fall. The best time is any time you see the black knot disease on the tree. Contact: 607-343-7781. Visit our website: https://www.blackknotbegone.com/