
Brown rot infected leaves of a cherry tree
Key Points
Disease Progression
- If the infected blossoms do not drop off, the fungus can grow through the flower stem (pedicel) and into the twig below.
- Twigs develop elliptical cankers with profuse gumming at the margin between diseased and healthy tissue.
- Leaves on these infected shoots turn brown and wither, but remain attached.
- Sometimes, twigs are girdled and killed.
- During wet weather in May and June, the fungus sporulates (produces spores which spread disease) on the surface of infected twig cankers.
- Cankers enlarge from season to season, and sporulation may continue on large cankers for 4 years or more.
- In rainy weather, the appearance of powdery tufts of brown-gray spores are visible on the outside of infected flowers, infected fruit, or twig surfaces.

Management
- In ornamentals, this disease is a relatively new problem and the control has not been studied extensively.
- Pruning blighted (diseased) shoots back to healthy tissue during dry weather may help, but is difficult if there is a large number of them.