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Sponsored: Control Ear Mold to Protect Yield

Untreated, corn ear mold can slash yield and open the door to mycotoxin development, potentially making the harvested grain unsuitable for consumption.

Properly identifying and managing molds, such as Diplodia, Gibberella, Cladosporium, Fusarium and Aspergillus, will help preserve your corn yield and allow you to deliver a high-quality crop to the elevator.

Identifying corn ear molds

To correctly identify ear molds, it is important to first consider the conditions in which the crop was planted, field history and environmental conditions at tasseling, silking and pollination. Also, consider husk type. Some molds are more prevalent on hybrids with tight or loose husks.

The ideal environment differs for each type of mold. Aspergillus, a grayish-green powdery mold, and fusarium, a white to pink cotton-like mold, often develop on damaged corn ears in hot, dry weather conditions. In comparison, cladosporium, a gray, black or dark green mold, and gibberella, a white to pinkish mold, develop in cool, moist conditions. Development of diplodia, a dense white to grayish-brown mold, often occurs when warm, moist conditions are present during silking.

According to Iowa State University recommendations, cornfields should be properly scouted to determine whether ear mold is present and, if so, the level of infection present. When scouting a field, growers should select a scattered sample of 100 plants or more. If more than 10 percent of the ears are found to have mold covering at least 25 percent of the ear’s kernels, that field should be considered infected with ear mold.

Minimize toxin development and manage moldy grain

Once an infected field is harvested, that field’s corn should be dried down to a moisture level of 15 percent or lower to prevent further disease development. Quickly reducing the moisture content also will aid in minimizing mycotoxin development.

Delaying harvest also can reduce toxin development if mycotoxin-forming diseases are present in a cornfield.

Moldy grain should not be stored. Instead, it should be immediately sold or moved through the appropriate channels. Grain destined for livestock should be tested for mycotoxins.

Plan for future years

To avoid ear mold development, growers should select a corn hybrid with ear rot resistance, reduce plant stress when possible and avoid planting continuous corn.

To learn more about corn ear molds and other agronomic topics, visit For guidance on variety selection, talk to your local Mycogen Seeds commercial agronomist or seed sales professional.

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