tar spot

noun

Definition of tar spot

  1. 1a :  a leaf-blotch disease of maple, willow, or oak caused by fungi of the genus Rhytisma that produces raised black stromatic cushions on the foliage b :  one of the spots produced

  2. 2 :  a disease of many grasses caused by a fungus (Phyllacora graminis) and resembling the tar spot of trees

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Origin and Etymology of tar spot

1tar


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