Bacterial canker

Bacterial disease common to stone fruits (cherry, plum, peach).

Also known as:
Bleeding Canker (Horse Chestnut)
Bacterial blight (Philadelphus)

Recognize bacterial canker
Bacterial canker, photo: Jerzy Opiola - CC BY-SA 4.0

Bacterial canker (Pseudomonas syringae). Bacterial disease common to stone fruits (cherry, plum, peach): it affects the stems and leaves of Prunus, especially plums and cherries. 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

    • Philadelphus
    • Cherry Tree
    • Horse Chestnut
    • Plum Tree
    • Peach
    • Tomatoes
    • Japanese cherry

Remedy

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