Meaning of crown rust

crown' rust"

Pronunciation: [key]
— Plant Pathol. Plant Pathol.
  1. a disease of oats and other grasses, characterized by the formation, on the leaves, of orange or black spores, caused by a rust fungus, Puccinia coronata.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.