Part 3: Vomitoxin – Wheat’s Formidable Foe

Grain Quality Part 3

Many factors impact your wheat yields throughout the growing season. Disease and weather can impact profits and factors such as grain damage, foreign materials, vomitoxin, test weight and moisture all play important parts in determining profits.

In part three of our five-part “Grain Quality” series, we discuss how Fusarium Head Blight (FHB) and its byproduct deoxynivalenol (DON), or vomitoxin, can impact profits and what you can do to lower risk from the disease.

If you missed our previous two pieces within the series, you can find them at the links here: Grain Damage and Foreign Materials.

Infection from FHBFHB and Vomitoxin

FHB typically infects wheat crops during wet weather periods and occurs during flowering. Purdue University says ideal temperatures for infection are between 75°F and 85°F. Long periods with high humidity can allow infection at lower temperatures. Infection can result in crop-quality issues like shrunken kernels, yield reductions and lighter test weights.

These quality reductions can also result from fungal mycotoxins produced during an infection.  Mycotoxins affect grain quality and can make it unacceptable for certain end-use production, thus demanding lower prices on the open market.

According to North Dakota State University, vomitoxin is the most common mycotoxin to affect wheat. As one would expect, this can be problematic when heavily contaminated grain is not fit for human consumption and can be discounted or completely turned away at market.

The impact of heavy DON outbreaks like that can be damaging. Reuters said that heavy outbreaks of the disease can be destructive to wheat growers, citing outbreaks that cost the U.S. wheat and barley industry $2.7 billion from 1998 to 2000 and then $4.4 billion in 2011.

Making matters worse, FHB may exist in a field for quite some time without clear symptoms during routine scouting. This makes handling FHB and DON difficult for many growers. But there’s a lot growers can do to reduce risk from DON and maintain high-quality grain.

Proactivity Proves Best

Agronomists and extension professionals agree, a proactive approach to DON prevention is the best way to limit losses. Brad Ruden, Director of Agronomy Technical Services,, says planning is your best friend for managing DON.

“There will always be a risk of FHB on winter and spring wheat, and growers that have an effective plan in place can limit their risk,” said Ruden. “Growers need to choose the best possible varieties available. Great choices are ones that provide the highest possible yields and strongest resistance to FHB.”

Ruden also suggests that growers examine their crop rotations to minimize wintering of FHB in crop residue. Planting wheat is better following crops that don’t play host to the disease like sunflowers, soybeans or peas. Yet, planting wheat after corn is risky because it holds a much higher level of FHB.

Another best practice that Ruden stressed was the use of strong fungicides, preferring Prosaro® over other products.

“During my time as a researcher at South Dakota State University, we saw the most effective control of FHB using Prosaro on both winter and spring wheat crops. The use of a premier product like Prosaro gives growers a competitive advantage over FHB.”

- Brad Ruden

In addition to using a premier fungicide, Ruden conducted multiple studies on fungicide applications at flowering, finding that full rates with high water volumes improved coverage multiple percentage points. “Cutting rates is a recipe for disaster. I recommend that growers apply fungicides with at least 15 gallons of water per acre in ground applications; 5 gallons in aerial situations.”

Thorsten Schwindt, Fungicides Product Manager for Bayer, stressed the importance of timing for a fungicide application.

“Fungicides like Prosaro should be sprayed early in the flowering stage to prevent disease from occurring in the plant. If weather interferes with ground applications, make an aerial application to limit crop damage, especially when disease pressure is high. The window for application lasts about 7-10 days.”

Schwindt also noted that Prosaro is the #1 product in the US in reducing DON levels in wheat crops making it a proven performer that growers can apply with confidence. This is due to a unique formula that contains multiple modes of action. “Growers should stay away from fungicides that include only a strobilurin ingredient as it can actually increase DON levels in wheat crops,” warned Schwindt.

Beyond timing, Ruden noted that obtaining 100 percent control for DON in your crop is not a realistic expectation. But there are other useful tools and best practices available to growers that limit damage, like increasing blower speed during harvest to expel lighter, shrunken kernels or using FHB risk predictors like those found at the US Wheat & Barley Initiative.

Check back next month, when we take a look at managing moisture levels in wheat.

Have a grain-quality story about wheat to share? Tweet us - @Bayer4CropsUS.

For more information about grain quality in wheat visit www.CropScience.Bayer.us, call 1-866-99-BAYER (1-866-992-21937) or talk with your local sales representative.

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