Meaning of sooty blotch

soot'y blotch'

Pronunciation: [key]
— Plant Pathol. Plant Pathol.
  1. a disease, esp. of apples and pears, characterized by sootlike spots or blotches on the fruit, caused by a fungus, Gloeodes pomigena.
  2. a disease of clover, characterized by black, crusty blotches on the underside of the leaves, caused by a fungus, Cymadothea trifolii.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.