How to Treat Apple Tree Cankers

Apple tree canker is a fungal disease of apple trees caused by Nectria galligena. The disease is also referred to as European canker and is characterized by the appearance of sunken areas on the bark. The fungus can infect apple trees during all stages of growth. Infected trees grow poorly, and the wood becomes highly prone to fracture during periods of high wind. There is an appearance of red spores in the cankers during fall. These resemble the eggs of red spider mites. The fungus usually enters the tree through wounds or pruning cuts made during fall. You can manage and treat apple tree cankers through a number of ways.

Sharp pruning scissors
Sharp knife
Bordeaux fungicide

Instructions

- 1
  Prune out all infected tree areas. Use a sharp, clean pruning tool and do not use an infected tool on healthy tree areas or other healthy trees without proper cleaning.
- 2
  Cut out the smaller shoots entirely if cankers are on shoots. If cankers occur on larger branches, carve out all the brown infected tree tissues with a sharp knife. The branch is then able to regain its health.
- 3
  Burn all pruned, infected tree parts. This minimizes spread of fungal infection.
- 4
  Treat infected trees by spraying affected areas with fresh bordeaux mixture at the rate of 10-10-100. Use the treatment during early fall prior to rains.
- 5
  Apply fungicide again after the tree has lost three-fourths of its foliage during fall. This is often necessary when trees are seriously infected. Bordeaux is an organic fungicide for treatment of apple canker.

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