tar spots of maple

Signs and Symptoms: A Tale of Two Tar Spots

  As noted earlier (http://bygl.osu.edu/node/525) there are two common tar spots of maple seen in Ohio.  One, that occurs commonly on silver and red maple results in dense, tarry spots caused by the fungus, Rhytisma acerinum. A second tar spot disease is typically found on Norway maple, with multiple tiny tarry spots that eventually coalesce into a larger spot, not quite as “tarry” but nonetheless black in color, caused by the fungus  Rhytisma punctatum.

 

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Published on
Authors
Jim Chatfield

Tar Spots of Maple

  Tar spots of maple, caused by species of the Rhytisma fungus, are prominent now, although mostly not as severe as in wetter summers. There are two different tar spot diseases of maple, one affecting silver and red maples, caused by Rhytisma acerinum, resulting in dense, tarry spots that truly reflect the “tar” spot name (first picture below).
Published on
Authors
Jim Chatfield