BLACK KNOT OF PLUM

DISEASED CANADA RED CHERRY

BLACK KNOT OF PLUM

LAST SNOW PHOTO OF THE WINTER

Tuesday,  8:30 AM.  32 degrees F, wind calm.  the sky is overcast but clearing and there is still haze and snow in the air.  The barometer stands at 30.08 in. and the humidity is 91%.  We got about five inches of slush dumped on us this morning that was too wet for even a large snowblower, so I shoveled  one side of the drive and the rest can melt.  I am taking no more photos of snow until next winter, assuming we ever have a summer.
   The reversion to winter has made us all want to go somewhere warm and sunny, so we are considering a Caribbean cruise, but really can't afford it.  Perhaps we could all be employed on a cruise liner; buddy as security, and Joan and I most likely as ballast.
   Black knot of plum is a serious fungal disease of most species and varieties of  plums and cherries, including some that are  used as street trees, such as the Canada Red Cherry shown here,  located at Ten N. Third Street.
   An infected tree or shrub develops large, pulpy tissue on new twigs, which eventually develops into hard black "knots" which girdle branches and  kill or seriously compromise the plant.  Early detection and removal of the fungal growth by pruning is necessary for control, as well as spraying with the proper fungicide.  When pruning infected growth it is essential to prune well below the knot, and then sterilize the pruning tool in bleach or alcohol before making another cut.  The fungus is technically named Apiospourus morubus.
   The above tree is so badly infected it must be taken down, and it will be buried or burned to prevent the spread of the disease, which spreads by arial borne spores.  We no longer plant Canada Red Cherry because of its susceptibility to the disease.