The spores are generally reddish brown, orange red to orange, and dry and dusty. Many plants, from grasses to pine trees, get rust diseases. A common experience is to walk through tall grass infected with rust and emerge with shoes coated in orange-red spores. The rust diseases produce several different spores, each spore capable of infecting a different plant. The cedar-apple rusts are a good example.
Rusts generally infect healthy, vigorous plants in preference to weak plants.
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