Fungal disease
Corn (Maize) Common Rust
A rust fungus that covers maize leaves in small cinnamon-brown pustules, usually in cool, humid weather.
Symptoms
- Small, oval, cinnamon-brown powdery pustules on both sides of the leaf
- Pustules turning darker later in the season
- Yellowing and drying of heavily affected leaves
What causes it
Rust spores blow in on the wind and infect leaves during cool, humid weather with heavy dew.
What you can do
- Choose resistant varieties.
- In a home garden, rust is often minor; remove the worst leaves if needed.
- Clear fallen leaves and plant debris at the end of the season, where the disease survives winter.
Not sure it's common rust?
Photograph one affected leaf and Plantulus will suggest the most likely problem, with a confidence score. It's free and needs no sign-up.
Check a leaf photoOther corn (maize) problems
General guidance only, not a diagnosis. Check product labels and local rules before using any treatment, and ask a horticultural specialist if a valuable plant is struggling. See the disclaimer.