Common Plant Diseases
Rust
Characteristics:
Most of the fungi known as "rust" attack ornamentals. They are named for the dry reddish, yellowish, or orange spore masses or pustules that form on the undersides of leaves. The spores are spread by wind and splashing water; avoid overhead watering.
Moderate populations apparently do not harm plants, but severely infected plants are stunted and may die. Remove rust-infected leaves and clean up fallen debris. Choose resistant plant varieties.