Tar Spot, Southern Rust and What Comes Next


By Tara Desmond February 19, 2026

On the latest episode of IL Corn TV, host John Klemm welcomes Ryan Gentle, Agronomy Manager with Wyffels Hybrids, for a wide-ranging discussion on what 2025 taught Illinois corn farmers and how those lessons should shape decisions heading into 2026.


Gentle, who covers the western half of Illinois from Galena to St. Louis, saw firsthand how dramatically different disease pressures impacted yields across the state. North of I-80, late-season tar spot and crown rot thrived after timely rains, with some fields seeing significant yield losses when fungicide timing didn’t align with disease onset. In some cases, growers who adjusted timing or made a second application saw 20–50 bushel differences.


Farther south, southern rust proved to be the bigger challenge arriving late and spreading rapidly. With a shorter disease cycle than tar spot, southern rust caught some growers off guard, leading to notable yield hits where fungicide strategies weren’t aggressive enough.


As farmers make hybrid and management decisions for 2026, Gentle cautions against reacting to a single year. “Look at multiple years of data,” he advises. Hybrids that excel against southern rust may not be the same ones that perform best in a tar spot year.


Beyond disease pressure, soil moisture is top of mind. Much of Illinois entered winter with significant subsoil moisture deficits. Gentle encourages growers to monitor soil conditions closely this spring, especially when evaluating planting windows.


For those using conservation practices like cover crops or strip-till, he recommends patience and awareness. Terminating cover crops ahead of planting, allowing soils to warm adequately, and avoiding sidewall compaction can help prevent early-season setbacks. He also reminds growers to scout for cutworm and armyworm, particularly in fields with heavy residue or winter annuals.


The key takeaway? Don’t abandon proven evaluation methods, just understand how changing conditions and management practices may shift your optimal timing.


Watch the full episode for deeper insights into disease management, planting strategy and protecting yield potential in 2026.


Not a member?

Become one today!

SHARE THIS

Latest Posts

shane and Andrew on il corn tv
By Tara Desmond June 18, 2026
What Illinois Farmers Should Know About the People Opening Global Doors for Their Grain
agronomy angle
By Matt from Becks June 18, 2026
Fungicide Timing and Today's Disease Challenges
milkdonation
By Tara Desmond June 18, 2026
In honor of National Dairy Month, Illinois farmers and IL Corn helped deliver thousands of pounds of milk to food-insecure families.
Evan Leeper
By Lyndi Allen June 17, 2026
Meet Evan Leeper, a fifth-generation farmer working ground in Macon County that his family has farmed since the 1850s. A former infantryman who farms alongside his father and brother-in-law.
U.S. Department of Agriculture Building
By Lyndi Allen June 17, 2026
U.S. Secretary of Agriculture Brooke Rollins announced a historic $125 million annual investment in agricultural research infrastructure across America, an opportunity for Illinois Universities
Baby with Corn Plastic Food Containers
By Pearl McDade June 12, 2026
Explore how corn is converted into PLA bioplastic for cups, food packaging, and 3D printing as demand grows for sustainable materials.
PCMthumbnail
By Tara Desmond June 11, 2026
PCM's 2026 Data Book, featured in this week's Prairie Farmer, shares 11 years of field data proving conservation and profitability go hand in hand.
By Tara Desmond June 11, 2026
How much do you know about the farmers who came before you and the decisions that still shape Illinois agriculture today? That's what University of Illinois student Lyndon Shi set out to explore during his internship with IL Corn . What began as an archival research project became a deeper look at the history of farmer leadership, innovation and advocacy in Illinois. While digging through university archives, Lyndon uncovered an undigitized manuscript from agricultural economist Harold Guither explaining the case for checkoffs. When he mentioned the discovery to IL Corn Director Rod Weinzierl, he got an unexpected response: "Oh yeah, I know him. We worked with him." It was a reminder that agricultural history isn't as distant as it may seem. Lyndon's research connected two eras of the IL Corn Growers Association: the original organization founded in the 1890s and the modern ICGA established in the 1970s. He learned how University of Illinois agriculture dean Eugene Davenport helped organize corn growers and sent professors across the state on "Corn Gospel Trains" to share the latest farming research. One story stood out in particular: the adoption of hybrid corn. Farmers who once judged corn by the appearance of the ear had to shift their focus to yield. Lyndon sees a similar transition today, as farmers increasingly balance yield with profitability amid rising input costs. "Illinois corn farmers are very good at organizing, and they are genuinely very grassroots," Lyndon said. "They've had a much more active role in shaping policy rather than just being on the receiving end." This Summer and Fall, Lyndon will travel to Taiwan on a federal scholarship to study food security. He'll do so with a new appreciation for Illinois agriculture's global connections, including Taiwan's longstanding role as an important trading partner. Watch the full conversation on IL Corn TV to hear Lyndon's research firsthand and discover how Illinois corn's history continues to influence the future.
Matt at USAPEEC Strategic Conference
By Tara Desmond June 11, 2026
IL Corn director Matt Raben was elected to USAPEEC's executive committee at the organization's 37th Annual Meeting this week.
Green world map with black curved arrows linking North America to Europe and Asia
By Lyndi Allen June 11, 2026
As one of the nation’s top agriculture exporters, Illinois ships corn to buyers across the globe—but where is it all going
Show More