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Pagoda Dogwood Branches Infected with Golden Canker Are Unlikely to Leaf Out

M. Grabowski, UMN Extension

Photo 1: Pagoda dogwood only partially leafed out. Dead branches were killed by golden canker.

M. Grabowski, UMN Extension Educator

Golden Canker, caused by the fungus Cryptodiaporthe corni, can easily be seen on the branches of Pagoda dogwood trees (Cornus alternifolia) this time of year. Infected branches and stems turn bright yellow with raised orange blister like spots. This diseased plant tissue clearly contrasts with the purplish green bark of a healthy Pagoda dogwood. Unfortunately branches infected with golden canker are unlikely to leaf out. The disease can continue to spread through infected branches and even into main stems. It can kill all above ground parts of the tree but will not kill the roots.

M. Grabowski, UMN Extension

Photo 2: Orange bark killed by golden canker contrasts sharply to healthy reddish purple bark.

The best time to prune out branches infected with golden canker is in March or February when fungal spores are less likely to be present to infect pruning cuts. If cold weather and deep snow prevented this from happening on time, however, branches can be pruned out on dry day. Make the pruning cut at least two buds below the visible discoloration of the bark. Be aware that in some case a canker spreads irregularly and discoloration may extend several inches longer on one side of the branch than on the other. Remove infected branches from the area. They can be burned, buried or taken to a municipal compost facility.
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