Gray leaf spot in corn.

Disease pressure varies from year to year, and as planting approaches, you may wonder which diseases could potentially damage corn in 2021. According to researchers at the University of Minnesota, gray leaf spot (GLS) is typically the most serious foliar disease in the Corn Belt.

GLS occurs nearly every growing season and was reported in 13 counties in IL alone last year. Because your bottom line could take a hit from GLS, we’ve provided answers to a few FAQs to help you prevent this disease from causing damage and yield loss.

When Could My Fields be at Risk for GLS?

The fungus causing GLS can survive on corn debris for more than a year, making the disease more severe in corn-on-corn acres. Additionally, stay mindful of your area’s weather conditions. GLS infection requires 11-13 hours of dew or fog while temperatures are warm.

How do I Identify GLS?

Early stages of infection appear as small lesions with yellow borders and are often confused with other diseases, such as anthracnose leaf blight, eyespot or common rust. Lesions become longer brown or gray-colored rectangles with yellow halos that run parallel to the leaf veins. As the legions spread across the entire leaf, the photosynthetic area is reduced, which can lead to stalk rots and lodging.

When Should I Apply a Fungicide?

Researchers at the Illinois University Extension say a pathogen, plus a susceptible plant host and a favorable environment, must be present at the same time for disease development. So, if a susceptible hybrid is planted in a field with a history of GLS, a preventive fungicide application between VT-R2 is recommended.

This season, consider a fungicide with broader disease control like Miravis® Neo fungicide. Packed with 3 modes of action, including Adepidyn® technology, Miravis Neo provides longer-lasting residual control and plant-health benefits for greener, cleaner corn crops resulting in more bushels more often.

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