Since 1993, wheat growers have battled scab and DON in an attempt to preserve yield, quality and profit, but little has been understood about how the infected grain affects food production.
After years facing the risk of hefty dockages at delivery, the entire wheat value chain is paying more attention to deoxynivalenol, or DON as it is commonly known, and the available weapons to fight against it.
DON is a toxic substance produced by Fusarium fungus that causes a disease in wheat and barley known as Fusarium head blight, or ‘scab.’ Because DON could pose a health risk to humans if consumed in high amounts, the U.S. Food and Drug Administration has set guidelines for maximum DON levels allowed in finished wheat products.
Any flour, bran, germ or other wheat product entering the food industry should not exceed a DON concentration of 1 part per million.
As vice president of grain supply for Siemer Milling in Teutopolis, Ill., Carl Schwinke takes on wheat quality as a priority. “We process all the wheat we purchase into flour for human consumption — cookies, pastries, pancakes, all kinds of batters,” he says. “Frankly, we eat, too. We want the safest food products reaching the end-user, so we want those DON levels to be as low as possible.
“DON affects everyone in the wheat value chain,” says Schwinke. “Producers' yields decrease, and they see more discounts for quality and grain damage. Marketing grain becomes a struggle for grain elevators as they may need to bin grain separately according to different levels of DON. Milling yields fall, as well as millers' profit margins. And the end user faces a higher cost for flour.”
When dealing with a wheat supply affected by a DON epidemic, the challenge for millers to maintain quality intensifies. Screening, airflow and gravity table equipment help separate smaller, under-developed scab infected kernels from the rest of the grain but at an expense and slow pace.
Adding the cleaning step to the milling process or at the elevator, though, won't eliminate DON from the grain supply. Late scab infections may show no visible kernel damage but could still cause elevated levels of DON.
Additionally, millers will need to source wheat from other regions when DON is not properly managed in their normal buying regions, which leads to additional transportation and freight costs. And compounding the issue of imported wheat is matching flour consistency — because imported wheat may not have the same milling characteristics as the regional wheat normally used. All these extra expenses add to the discounts growers receive when they sell scabby wheat and how ultimately, the end consumer is affected.
Randy Myers, Bayer CropScience fungicide product manager, says a growing number of U.S. wheat and barley producers are relying on annual fungicide use as a proactive measure for overall crop protection.
“Annual, proactive approaches to disease management are the most effective because scab on cereals cannot be cured,” he explains. “If warm and humid climate conditions along with a moist soil surface are present as grain heading approaches and the Fusarium pathogen is present, disease will develop. You don't want to wait until you can see signs of the disease to spray, because then it's too late to get the most out of your fungicide applications.”
Mark Huso is a retailer and crop advisor with Lake Region Grain in northeastern North Dakota. He makes recommendations to his growers based on what will provide an economic advantage to them and what will produce a high quality crop for his company to sell.
In 2008, Huso administered a strip field trial to observe the new Prosaro fungicide from Bayer CropScience.
“Although the season was virtually disease-free, the gains in yield, protein levels and test weight gave the wheat treated with Prosaro an economic advantage over non-treatment and the other fungicide,” says Huso. “In my view, my customers need to look to this level of control to produce the highest quality wheat they can in their fields.”
Across all kinds of conditions, Prosaro has been proven to reduce mycotoxins by 50 percent to 60 percent. “In years of heavy scab pressure, this level of reduction could mean preserving the marketability of a crop,” says Myers. “In years of lighter pressure, it means producing an even better crop than expected and helping to secure premiums for high grades.