Tar spot in corn

With the corn and soybean growing season coming to a close, it’s important to look back on 2020 to gain insight for next year. By identifying key diseases from this season, you can plan for diseases that overwinter and will likely reappear next year. Read more below to see the diseases identified at one of our Grow More^TM Experience sites.

Corn Diseases in 2020

One corn disease found at our Yarmouth, IA Grow More Experience Site was tar spot. Tar spot can lead to significant yield loss, weak stands and an early dry down. A sporadic threat in past years, tar spot continues to spread in the Midwest with reports of infection in IL, IA, IN, MI, MN and WI.

Gray leaf spot (GLS), a more common threat, was also found at the site, and according to the researchers at the University of Nebraska-Lincoln, by early August it was increasing in severity in NE. Because crops can be infected for a long period of time before lesions appear, you may not be able to rely on scouting alone in 2021 to stop this disease before it impacts yield.

Both tar spot and GLS pathogens overwinter on corn residue and could emerge next season to infect new plants. When you add in long latent periods and devastating yield effects if left unchecked, these diseases can be a significant threat, and we encourage you to plan for a preventive fungicide application in 2021.

Soybean Diseases in 2020

A widespread disease, it was no surprise frogeye leaf spot (FELS) appeared in our IA site’s trials. What may be new to you is many of the FELS infections in IA were strobilurin-resistant. Common in the South but spreading to the Midwest, there were 73 cases reported in IA in 2019, according to Iowa State Extension plant pathologists.

To help you reap more bushels in 2021, we recommend Miravis® Neo fungicide for preventive disease protection. With excellent efficacy when applied early at V4-V8 or later at VT/R1 in corn and at R3-R4 in soybeans, Miravis Neo delivers consistent, broad-spectrum disease control to protect corn and soybeans from tough diseases like tar spot and strobilurin-resistant FELS. Plus, it’s the only product on the market with 2 active ingredients that provide plant-health benefits for cleaner, greener crops you can see.  

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