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Don’t Let Disease Dock Corn at the Elevator

October 7, 2016

Pulling a full semi of corn into the elevator should be a time to bring in the big bucks. But some Illinois growers are getting hit with devastating dockage fees – up to 70% – for having such severe disease prevalence on their kernels. Diplodia, Gibberella and Nigrospora, or cob rot, are the top three disease corn growers are facing this harvest season. When crop scouting, make sure to inspect at least 10 ears across multiple locations before calling your field clean. Here’s how to identify if one of these diseases is an issue:

  • Diplodia: Diplodia is causing most of the disease damage for Illinois growers this year. Marked by a coating of white, non-toxic mold, the pathogen starts toward the bottom of the ear and works its way up. Diplodia can even be marked by white mold on the outside of the husk. Taking a closer look at Diplodia-infected grain and corn cobs, small black dots, signs of disease spores will be present. Although genetics play a role for this disease, weather is the greatest factor. High amounts of rain during early pollination increases the chances of Diplodia development.
  • Gibberella: While Diplodia is white, Gibberella is pink when the disease is fully developed. This disease works its way from the top of the corn ear to bottom. Spurred on by cool, wet weather during the first 21 days after silking, Gibberella mold can grow between the husks and ear, as well.
  • Nigrospora: Also known as cob rot, Nigrospora is deceiving because it can’t be detected from the outside. Rather, the cob is spongy, and the disease is brought on by a stress-induced environment, such as frost, drought, root injury, leaf blight or stalk rot. Since spongy cobs are more difficult to harvest, growers need to adjust their combines to maximize kernel removal and minimize cob breakup. This is best accomplished by finding the right combination of rotor speed and concave opening.


The corn ear on left is infected with Diplodia, while the ear on right is not. Rotating from corn to soybeans each year helps reduce the possibility of Diplodia disease outbreak.

To prevent Diplodia, Gibberella and Nigrospora, rotate from corn to soybeans to break the cycle of pathogen buildup. When it comes to controlling leaf diseases, spray an application of Trivapro® fungicide at R1, when necessary. With three active ingredients, including Solatenol® fungicide, Trivapro delivers long-lasting disease control and crop enhancement benefits to maximize yield potential.

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All photos are either the property of Syngenta or are used with permission.