apple rust

noun

Definition of apple rust

1 : any of several diseases caused by fungi of the genus Gymnosporangium especially : a destructive fungal disease especially of the apple but also attacking pears and quinces that is caused by a rust (G. juniperi-virginianae) having its pycnial and aecial stages on the leaves and fruit of the apple and the telial stage on species of Juneperus, especially a common red cedar (J. virginiana)
2 : the fungus causing apple rust

called also cedar apple rust, cedar rust

— compare cedar apple

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Comments on apple rust

What made you want to look up apple rust? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to fake an opponent out of position

Get Word of the Day daily email!

Test Your Vocabulary

Where in the World? A Quiz

  • peter bruegel tower of babel painting
  • What language does pajama come from?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Citation

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!