Season 1, Episode 8
Harvest Insights: Lessons, Data, and Disease Takeaways from 2025
The 2025 growing season is wrapping up but the learning never stops here at Renk Seed. In this episode of Renk Seeds of Innovation, Max Renk is joined by Karl Bobholz, Alex Renk, and Jeff Renk to share what they saw across the Corn Belt this year.
As Alex mentioned, “this year was all about top-end yield,” while last year was all about stress. And together, they tell the story of what stable genetics can really do.
From Southern Rust and Sudden Death Syndrome to nitrogen management and emerging biologicals, the Renk team breaks down the wins, surprises, and lessons shaping seed performance. They also unpack what plot data reveals about hybrid performance, product selection, and stress-year testing—and how we can turn these insights into smarter decisions for your acres in 2026.
A Season of Stability—With a Few Surprises
This year, many Midwest growers experienced what could be called a “normal” season, with less weather drama than previous years. However, there were notable disease outbreaks—Southern Rust and Tar Spot—especially in the Corn Belt. Karl noted that fungicide timing made all the difference: fields sprayed too early ran out of protection, while products like RK773TRE and RK8585TRE stood out for their disease resilience and yield in trials. Another new product, RK4545AV, shows strong promise in Wisconsin and Minnesota.
...fungicide timing made all the difference: fields sprayed too early ran out of protection, while products like RK773TRE and RK8585TRE stood out for their disease resilience and yield in trials.
Disease Pressure and the Importance of Timing
Jeff recounts his “windshield farming” travels across the region, observing that disease was the year’s defining story. Additionally, he calls for urgency in harvesting the crop in a timely manner given the large crop hanging on the stalks. The main advice: “Get it in before it’s on the ground.”
On the soybean side, Alex recounted high rainfall resulting in solid yields—some topping 100 bushels—but sudden death syndrome (SDS) arrived late to remind everyone that not all varieties can overcome every challenge. Curiously, white mold was less of an issue, likely due to a hot and wet summer, an environment in which the fungus doesn’t thrive.
Karl and Jeff emphasized that both the timing and method of fungicide application were critical.
Lessons in Fungicide Application and Nitrogen Management
Karl and Jeff emphasized that both the timing and method of fungicide application were critical. Many growers sprayed early to protect their best fields, but this left them exposed later in the season. Equipment limitations and reliance on custom applicators resulted in not all acres receiving timely treatment. Spray drones, while promising for targeted rescue applications, aren’t a full replacement for ground or aerial rigs—especially when large acres are at stake.
Nitrogen management also played a role, with some growers cutting back due to rising costs. This added stress to the plants, leading to more stalk issues. We can all agree that balancing input costs and plant health is a delicate act.
Plot Data: Two Years, Two Extremes
Looking at plot data, Alex and the team emphasize the importance of comparing products across both stressful and high-yielding years. Last year’s stress tested genetic resilience; this year’s favorable conditions revealed yield potential. Combining both datasets helps identify varieties that are not only top performers but also reliably stable—ideal for building a robust lineup for growers.
Product Selection: Balancing Yield, Disease, and Grower Needs
The team agreed that product selection is about more than just chasing the highest yield. Disease package, stress tolerance, and fit for specific environments all matter. Renk Seed’s decision to keep or cut a variety depends on consistent performance across years and growing conditions, as well as, the practicalities of storage and production.
Breeding and Genetics: Learning from History
Jeff and Karl discussed the long game in breeding—great hybrids emerge only every five to ten years. DroughtGard®, for example, became a staple because it delivered both stability and yield, particularly in challenging conditions. The lesson: look for products that perform not just in good years but also when times are tough.
...look for products that perform not just in good years but also when times are tough.
Beyond Seed: Value-Biological Innovation
Karl shared some behind-the-scenes research into biological seed treatments and their potential to unlock soil fertility and reduce input costs. Early data is promising, but repeatability and consistency are key before recommending these products broadly. The team is also evaluating how such treatments impact disease resistance, particularly for stalk rot.
Key Takeaways for Growers
Scout and Act: Monitor fields for disease and harvest in a timely manner to prevent losses.
Fungicide Strategy: Prioritize correct timing and coverage, avoid relying solely on new tech like drones for large-scale application.
Genetic Diversity: Choose your seed from products proven effective over multiple seasons and various stress environments.
Input Management: Balance cost-saving measures with the need for plant health and resilience.
Stay Curious: Follow ongoing research into biologicals and other value-added practices that may soon benefit your operation.
Final Thoughts
Every season offers new lessons. By combining plot data, field observations, and a willingness to try new approaches, both Renk Seed and our growers are better positioned for success—whatever next year may bring.
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