Rust Disease: Identification, Control & Prevention

Rust is a fungal parasite requiring living hosts. It rarely kills but reduces vigor, health, and flower production across many woody and herbaceous plants. Spores spread by wind and water—wet surfaces enable infection. Mild, moist conditions favor outbreaks.

Identification

• Yellow/white spots on upper leaf surfaces.
• Reddish-orange pustules (blister-like) on leaf undersides.
• Orange/yellow streaks on undersides.
• Spores within spots.
• Leaf distortion and defoliation.

Think of the rust on an old bicycle—that's the look.

Control

• Remove and destroy all infected parts. For brambles, remove entire plants and replant resistant varieties.
• Clean debris between plants.
• Avoid splashing water on foliage.

Prevention

• Dust with sulfur early season.
• Space plants for air circulation.
• Water soil, not leaves.
• Consult local nursery for effective rust fungicides.