sooty blotch

noun Plant Pathology.

a disease, especially of apples and pears, characterized by sootlike spots or blotches on the fruit, caused by a fungus, Gloeodes pomigena.
a disease of clover, characterized by black, crusty blotches on the underside of the leaves, caused by a fungus, Cymadothea trifolii.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018