By Andi Anderson
In 2024, Midwest oat farmers faced a surprising disease threat—Fusarium Head Blight (FHB). While crown rust is a common concern, unseasonably warm and wet conditions triggered FHB outbreaks, particularly across southern Minnesota, northern Iowa, and southwest Wisconsin.
The fungus Fusarium graminearum, which causes FHB, thrives on warm, humid days and survives in corn and grain residue.
That’s why rotating oats after corn can increase disease risk. Many oat samples showed high levels of deoxynivalenol (DON), a toxin that remains undetectable externally but can contaminate grain above safe limits. Some samples exceeded 4 parts per million, far above the 2 ppm market standard.
Jochum Wiersma, a small grains expert at the University of Minnesota, explained that oat panicles typically dry quickly, preventing FHB infections. But the consistent wet weather in 2024 allowed the disease to take hold. Cleaning infected oats didn’t lower DON levels much, unlike wheat. This means farmers must prevent FHB, not rely on post-harvest strategies.
Currently, few oat varieties are tested for FHB resistance. Without resistant options, farmers should use fungicides like Miravis Ace and Sphaerex, especially when weather risk is high.
However, timing is tricky—fungicides for crown rust are usually applied earlier than for FHB. Applying once for both diseases may not be effective, but applying twice may be too costly.
Fungicide coverage is essential. Using forward and backward nozzles ensures the oat head is well-coated. Farmers are encouraged to consult guides like North Dakota State University’s FHB spray application recommendations.
Organic farmers face greater challenges since fungicides are not allowed. However, new research is underway. Jochum Wiersma and Kevin P. Smith received funding in 2025 to study FHB prevention and resistance breeding in oats.
With better understanding and preparation, oat farmers can manage FHB risks and protect future harvests.
Photo Credit: gettyimages-shotbydave
Categories: Iowa, Crops, Weather