Bacterial canker is a fungus particularly common on cherries and plums. The disease weakens the plant and can cause extensive die back if not treated. Plants growing in poorly drained soil are more susceptible to this disease.
These vary depending on the plant but generally seen as damaged bark on the stem. Look for swollen stems oozing sap.
Treatment and control
Spray with a suitable fungicide: For canker on plums and cherries treat with a copper fungicide (containing copper oxychloride) three times a year: mid-August, mid-September and mid-October. For other plants prune out the affected area. Maintain good hygiene and burn all prunings. Copper fungicides also control peach leaf curl, bacterial canker (plums, cherries), rust (currants, gooseberries), cane spot and prevents damping off in seedlings.