Adapt to Evolving Disease Pressure in the Corn Belt

For many corn growers, 2025 was a tough year for foliar diseases, as unrelenting rain and high humidity levels fueled extraordinary pathogen pressure. One notable anomaly was the widespread, extremely high severity of Southern rust into the northern Corn Belt. In 2025, Southern rust was reported in 20 states and as far north as Minnesota and South Dakota, leading many extension specialists and agronomists to name it a top threat to corn yields.

Southern rust wasn’t the only disease wreaking havoc on corn yield. Tar spot, Northern corn leaf blight and gray leaf spot were reported in many fields; and Fusarium/Gibberella ear rot became an increasing concern when heading to the grain elevators. For added complication, this intense disease pressure appeared sooner than usual, requiring many growers to spray a yield-saving fungicide earlier in the season. High demand also created difficulty in finding applicators available to spray quickly.

Ben Van Roekel, a second-generation farmer in Iowa, experienced these challenges firsthand. “On July 7, we found tar spot, Northern corn leaf blight and Southern rust already in our field, which was early for us,” he says.

Fortunately, Van Roekel was able to respond quickly with an application of Miravis^® Neo fungicide to help protect his corn yields. “We’ve had record rainfalls for July and August, so getting applications out there was really challenging,” he says. “After that, we had high humidity and strong dews in the morning along with the constant rainfall, causing probably one of the strongest disease years that I have ever seen in my entire career.”

The Benefits of a Proactive Fungicide Strategy

The movement of Southern rust and the reality of unpredictable weather conditions serve as reminders for how important it is to stay ahead of diseases. Instead of waiting to see what diseases show up each year, planning a proactive fungicide approach can give you peace of mind that no matter what diseases the growing season brings, your yield will be protected.

Syngenta has a portfolio of fungicides that help fight diseases, increase plant health and boost yield potential — even in low pressure years. One top choice is Miravis Neo fungicide, which contains the unique powerhouse carboxamide SDHI molecule ADEPIDYN^® technology. Miravis Neo fights all key corn diseases, dominating spots and blights as well as protecting grain and silage from mycotoxin-causing Fusarium/Gibberella ear rots.

Another proven option is Trivapro^® fungicide, a long-lasting corn fungicide that delivers preventive and curative control of diseases through three modes of action, including SOLATENOL^®.

Recent data from the University of Kentucky shows Miravis Neo and Trivapro both continue to outperform other fungicides at reducing Southern rust severity.¹

Yield Protection With or Without Disease Pressure

As important as it is to anticipate disease pressure, there are always years with drier conditions and fewer diseases to contend with. Fortunately for growers, research shows that Miravis Neo and Trivapro are still good investments in years without heavy disease pressure, protecting plants from stress and boosting yield potential through unrivaled plant-health benefits like more efficient uptake of water and nutrients.

Cleaner & Greener* fungicides give growers dual-yield protection from disease and stress like drought, in both heavy and low disease pressure. (References to “cleaner and greener” indicate plant health benefits (e.g., less disease and increased crop efficiency and productivity) from foliar fungicides and the visible color of the plants.)  Data across six years and over 700 strip trials show that Cleaner & Greener fungicides were profitable 80% of the time, regardless of whether it was a dry or wet growing season.²

“Quality fungicides, like our Cleaner & Greener portfolio, are really the most important tools out there for preserving yield potential,” says Tyler Harp, technical product lead at Syngenta. “These tools also help protect the investment growers make in their crops each year, so they can get more bushels per acre at the end of the season.”

Under the heavy disease pressure and unfavorable growing conditions seen in 2025, Van Roekel’s Miravis Neo-treated corn yielded 30–50 more bu/A than his two untreated checks.

In recent years, Van Roekel’s acres have struggled with drought instead of disease, and he still credits the stress-relieving properties of Miravis Neo with helping his crop thrive.

“I’ve always liked Miravis Neo with the ADEPIDYN technology in there to keep the plant green and keep it healthy,” Van Roekel says. “I’ve really liked Miravis Neo on those aspects of plant health.”

*No claim is being made herein about the environmental attributes of any product. References to “cleaner and greener” indicate plant health benefits (e.g., less disease and increased crop efficiency and productivity) from foliar fungicides and the visible color of the plants.

¹ Trial USNG0F325-2025, University of Kentucky, Dr. K. Wiess, 2025.

² Based on application + product cost and corn price $6.00/bu. Data from 709 on-farm grower/strip trials from 2016-2022; AR, IA, IL, IN, KS, MN, MO, NE, NY, OH, SD, WI. Trivapro and Miravis Neo at 13.7 oz/A