Ornamental Rust is a fungal disease that affects ornamental and edible plants in wet and humid conditions. It is caused by many different species of fungi in the genus Puccinia. Some types infect only one type of plant.
Rust is identifiable by powdery, orange- to red-colored spores grouped in pustules on the underside of affected leaves and sometimes stems. Yellowish spots also appear on the upper leaf surface. Roses, Chrysanthemums, beans and Snapdragons are some of the common plants that can be infected with Rust.