Prune diseased branches. Prune out all affected branches and burn or remove them from the site. Prune in late winter when it is sunny and the trees are dry. After pruning, oil blades to prevent rust. Avoid injuries to bark and stems.
Wounds can provide entry point for the fungus especially during wet periods.
Improve plant health. Water during dry periods and aerate the soil around the tree to relieve soil compaction and facilitate water and nutrient penetration. Fertilize the tree in the fall. Maintain good air circulation. Chances of infection are greater on plants that are crowded together.