Rust
Puccinia and uromyces sp.
- Small yellow, orange or red raised blisters on leaves and stems
- Powdery orange spores brush off infected leaves and can be seen on a white tissue
- Leaf tissue around the rust spots turns yellow and sometimes brown
- In severe cases rust spots may merge together to form large yellow or orange streaks or blotches
- Severely infected leaves may turn brown, dry up and die
- Rust spots become dark brown or black late summer and early fall
