DISEASE?? japanese maple

Mixborders mixborders at aol.com
Sat Jan 11 09:24:54 EST 1997


I believe that the spots on the trunk of your Japanese maple indicate the
presence of Cercospora canker, which is a common disease of these trees.
Generally, these cankers are the result of some sort of prior injury to
the trunk, perhaps an old wound (from an improper pruning cut, or other
damage caused by cold temps, etc.) I don't think there is any real cue for
it other than to prune the branch off cleanly at a spot below the canker,
where there is green tissue that completely surrounds the trunk. A book on
pruning would be recommended if you rae unsure how. Be sure to sterilize
the saw after the cut is made with a bleach solution, and don't apply any
wound dressings on the tree. Promote good tree health by watering during
drought and avoid the excess use of fertilizer. A good mulch will also
benefit.



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