Meaning of stem rust

stem' rust"

Pronunciation: [key]
— Plant Pathol. Plant Pathol.
  1. any of several fungal diseases of plants affecting the stems, esp. a disease of wheat and other grasses characterized by pustules of red and then black spores.
  2. any of the fungi causing such a disease.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.