Also known as:
Bacterial blight (Philadelphus)
Also see:
Horse chestnut bleeding canker
Bacterial canker (Pseudomonas syringae). Bacterial disease common to stone fruits (drupes): cherry tree, plum, peach: it affects the stems and leaves of Prunus, especially plums and cherry trees. Also apricots, peaches and Prunus ornamental trees are susceptible. Sometimes found on horse chestnut: Pseudomonas syringae aesculi.
High humidity in spring and fall promote the infection. It starts in the leaf and moves to the bark. The bacteria penetrate the tree through pruning wounds and frost cracks.
Often gummosis occurs as a secondary infestation.
Affected plants
-
- Mock orange (Philadelphus)
- Cherry Tree
- Horse Chestnut
- Plum Tree
- Peach
- Tomatoes
- Japanese cherry
Control
Once infected, the bacterial canker is difficult to to control; sometimes removing the infected parts helps.
Prevention
Prevent infection by:
– prune during dry weather
– seal pruning wounds
– remove prunings
