How to Treat Bacterial Canker on a Cherry Tree

Bacterial cankers cause cherry tree orchards to lose up to 75 percent of their crops, according to Oregon State University. Symptoms of this highly destructive disease include bark discoloration, sunken areas, oozing, leaf yellowing and girdled trunks. The overall health of the cherry tree declines if proper treatment is not employed. Cherry trees younger than eight years old are at the highest risk of succumbing to this bacterial disease.

Pruning saw

Fixed copper spray

Bordeaux spray

Propane burner

Sterilize the pruning tool with a mixture of 70 percent denatured alcohol and 30 percent water. Make 45 degree, downward pruning cuts into the healthy branches to remove diseased wood. Cut four inches on either side from the diseased portion. You can remove an entire branch by making a pruning cut next to the branch collar of the cherry tree. The swelling that attaches the branch to the main trunk is the branch collar. Clean pruning tools after every cut.

Pick up all debris underneath the cherry tree. Remove all grass growing underneath the tree by hand pulling them out of the soil. Grass can harbor the bacteria that causes the infection.

Apply a fixed copper or Bordeaux spray to your cherry tree in the spring and again in the fall before bud break.

Cauterize the branch canker with a propane burner in early to mid spring. Hold the burner up to the canker for 15 to 20 seconds.

Burn the canker again in two to three weeks. Make sure that the underlining bark tissue crackles before removing the flame.

Prune your cherry trees in the summer to prevent future bacterial canker infections. Pick a time when you are experiencing dry weather.

Avoid fertilizing your tree with excessive amounts of nitrogen, which encourages winter injury and bacterial cankers.