Leaf diseases can rob your cornfields of significant yields if left unchecked when environmental conditions favor disease development. One big piece of the puzzle to preventing yield loss is to be able to identify which diseases are in your fields.

“You need to catch foliar diseases through routine scouting so you can make informed decisions about spraying fungicides on a field-by-field basis,” says Nick Dame, U.S. product manager for fungicides for Corteva Agriscience.

A key to making correct product choices once you’ve decided a field should be sprayed with a fungicide is to identify the diseases in the field correctly, Dame continues. Different fungicides offer varying levels of control against specific diseases. Read label information carefully and determine which active ingredients a product contains. Make sure the product is effective against the diseases you are most concerned about.

To help you identify diseases, here is a slideshow with photos of some of the more common foliar diseases in corn. Thanks to Corteva and Ceres Solutions for providing these photos.

Information for identification of these diseases included in the captions is provided by the Purdue University Corn & Soybean Field Guide. It’s prepared by the Purdue Crop Diagnostic Research and Training Center, directed by Purdue agronomist Corey Gerber.

The 2020 edition of the guide is now available. Order at edustore.purdue.edu. The Corn Field Guide app and Soybean Field Guide app for cellphones are available at nominal cost from app stores.