Problem: Bacterial Canker
This plant disease, also known as bacterial gum-mosis or bacterial blast, is found on various fruit and nut trees but is most severe on cherries. This disease is caused by bacteria (Pseudo--monas syringae). Splashing rain spreads the bacteria to dormant buds, twigs, and branches. Infection occurs through wounds in the twigs and branches, and bacterial decay causes cankers to form. During the fall, winter, and early spring, large quantities of bacteria-containing gum ooze from the cankers. Bacter-ial activity decreases in the summer. Slowly developing cankers may encircle a branch, however, and by midsummer, affected branches and limbs start to die back. With the onset of cool, wet, fall weather, bacterial activity in-creases again. This disease is most serious on young trees.
Bacterial canker is difficult to control. Prune out diseased branches. Disinfect pruning. Prune in late winter or early spring rather than early in the dormant season.