Photo and text used courtesy Clemson University
Cooperative Extension Service.

There are several different leaf diseases caused by different species of this fungus. The spots often enlarge and increase in number to cause severe leaf blighting. Such damage can ultimately lead to increased stalk lodging as well as reduced yields and quantity of grain. The damage is more severe in fields where conditions are wet and humid, with poor air movement for extended periods of time.

The fungi survive on old corn debris and may be carried on seed.