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Black Knot fungus of Cherry Trees PDF Print E-mail
Written by Dawn   
Wednesday, 25 March 2009 22:30

Black Cherry Tree blossoms Black Cherry Tree Bark  black knot of cherry

Black knot fungus on Cherry Trees becomes active in the spring right around the time of budbreak.  This disease, cosmetic at first, can severely distort and weaken cherry trees.  It is often found in natural wooded areas as well as in our landscape and even our cherry orchards.  I see it all the time in Oakland County.  We are lucky to have many native black cherry trees.  In fact it's one of my favorite trees.  Characteristic dark scaly bark, thin whispy branches, beautiful little flowers and fruit for wildlife.  An important tree ecologically.  I have several on my woodlot and I noticed one small tree in particular that was infected with a couple knots last spring.  I never got around to pruning them out.  I am amazed at how quickly it multiplied.  It is the end of March now and it has been a warm month.  Maple trees were in full bloom on the first day of Spring!  Buds are breaking, which means the spores will be active on days that are wet and over 60 degrees - spring in Michigan.  We had a few warm dry days, so I went out and pruned mine off, disinfecting my pruners in between cuts.  The pruned out infected branches must be removed and burnt, or disposed of.  I would not compost or chip it - those spores will survive almost anything.  The infected trees are best pruned during winter dormancy, but I figure -  the sooner the better and better late than never.  If pruning after the dormant season - disinfect your tools after every cut and don't do it on a rainy day!