- Sunken, circular patches that measure several inches.
- Patches turn from brown to straw color and may eventually coalesce, forming irregularly shaped areas.
- May display small lesions that turn from yellow-green to straw color with a reddish-brown border.
- Lesions can extend the full width of the leaf.
Conditions Favoring Disease:
- Continuous high humidity at temperatures between 59F and 86F.
- Favored by warm days, cool nights, and intense dews.
- Infects areas with low levels of nitrogen.
- More severe in dry soils.