A Wheat Growers Perspective of DON

LL photo_blogDeoxynivalenol (DON) outbreaks have a significant impact on farmers today and can be very challenging and complex to manage. To gain some insight on managing these outbreaks appropriately, Neogen recently talked with Laird Larson, a wheat farmer who provided his perspective from his 20 years of experience dealing with DON outbreaks.

Q: Can you describe the tools available to wheat and barley growers to potentially prevent and/or reduce DON?

A: First and foremost, it’s important to understand that DON is a mycotoxin that appears as a result of the fusarium head blight (FHB) disease. Usually, the correlation between the two is that with the higher levels of FHB, you will have higher concentrations of DON. That being said, controlling FHB, or scab, is most important to reducing DON levels.

To accomplish this, the use of FHB resistant varieties of crops would be my first choice. Most breeders give a rating of resistance to their varieties and it’s also important to avoid planting on corn residue ground, as corn is a host for the fungus.

In addition, approved fungicides that have been proven effective against FHB should be applied at anthesis or flowering of the crop heads, which is a very timely application.  There is a scab forecasting tool also available that watches the weather forecasts and predicts the potential risk of getting scab, which farmers should pay close attention to. Weather has a strong influence on the amount of FHB and DON, therefore even the best defenses can be broken.

Q: What are the challenges with the tools listed above and how successful can they be?

A: While these are all helpful tools, these practices will only be 60-80% effective. However, anything done to reduce FHB will also reduce the mycotoxin DON levels to where they can be managed throughout the food chain.

Q: If DON is inevitable in the crop, is it possible to reduce DON levels and what are these practices?

A: Research science is constantly studying and testing for methods that can reduce DON.  In fact, the U.S. Wheat and Barley Scab Initiative (USWBSI) spends over $5 million dollars each year to gain insight on this devastating disease. However, time and money are still needed to further understand its complexity and relationship to mycotoxins, for developing the best practices that can achieve control.

Q: How challenging are these practices and how successful can they be?

A: Understanding both the wheat or barley plant and the disease seem to be crucial for achieving anything close to complete control.  Although fungal control can be aided with fungicides, resistance from within the plant appears to be the best form of control at this time.

Q: What do you think the future holds for managing DON?  Do you think this is something that can be eliminated or significantly reduced with new technologies, tools and/or practices?

A: I believe we will find ways to significantly manage and reduce infected crops in the future, but will probably never be able to completely eliminate DON. However, in the 20 years I have been studying and working with the disease, many advancements have been made.  For example, we have identified and eliminated severely susceptible varieties, found approved practices to lessen infections or the spreading of the FHB, and discovered which fungicides work best and with what application practices.

Although progress comes slow, we are already much better off today than we were 20 years ago. By remembering past events such as those that caused the burning of thousands of acres of infected crops and threatening to never plant wheat or barley again, we have come a long way. Now, as genome work continues to advance, we will be able to learn more about what breeders can do to build resistance to the disease at even higher levels.

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