Southern Rust
Symptoms:
- Pustules are circular to oval, and light cinnamon brown to orange
- The pustules will be mainly scattered on the upper surface of the leaf, however a few pustules may be seen on the lower leaf surface
- Pustules may also appear on husks, ear shanks, stalks, and leaf sheaths
Pathogen Involved:
- Puccinia polysora (a fungus)
- Overwinters in the southern U.S. and Mexico (not in the corn belt)
- Urediniospores serve as the repeating stage of this fungus and are blown north to the corn belt in the early summer
- This pathogen most often is present in the southwestern United States, but spreads to the U.S. corn belt in some years
Time of Occurrence:
- This disease occurs most often after the silking of corn
- june to August
Conditions Favoring Disease:
- Warm temperatures and high humidity
Disease Management:
- Primarily is controlled by planting resistant corn hybrids.
- A protectant fungicide or a locally systemic fungicide may also be used against southern rust