Just Call Me Doctor

Dr. Chokecherry, that is.  Today I played doctor to our favourite chokecherry tree.  The birds love the berries produced by this tree and they make delicious jam.

While waiting with Liam for the school bus, I noticed some black fungus spots had appeared on two of the tree's branches.

Black Knot, caused by the fungus Apiosporina morbosa, is a common disease affecting chokecherry and other trees in the genus Prunus.  These include:

Amur Cherry	Mayday Tree
Apricot	Mongolian Cherry
Black Cherry	Nanking Cherry
Chokecherry	Pin Cherry
Dropmore Cherry	Cultivated Plum
Flowering Almond	Wild Plum
Flowering Plum	Prunus Hybrids
Japanese Plum	Sand Cherry
Korean Cherry	Sour Cherry

We have plum and cherry trees planted nearby so I want to try to keep the Black Knot under control. The most distinguishing symptom of Black Knot is the characteristic black, tar-like swellings that develop on branches of the infected plant. 

To control Black Knot it is recommended to prune out all knot-bearing branches during late fall, winter or very early spring when plants are dormant and knots are easy to see. I cut the infected branches back to the tree trunk and put them into a compost bag. I will put them out for the friendly neighbourhood compost man next week.

Well done, Dr. Chokecherry. 

Reference:

Alberta Agriculture and Forestry.  (2003). Management of Black Knot.  Retrieved from: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/faq7622?opendocument

What?!  Did you think I had actually finished my doctorate?