Wheat School: Don't be too eager to spray for fusarium

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Fusarium head blight is one of the most harmful diseases of wheat and also one of the most challenging to manage.

Researchers are continuously trying to figure out the best control methods since it’s one of those diseases that if you see it in your crop, you are most likely too late.

In this Wheat School episode, Kelly Turkington, research scientist at Agriculture and Agri-Food Canada, tells Kara Oosterhuis that the tools that are currently available only really provide suppression at best.

“In a situation where you have high risk, even if you have a combination of resistant variety, a fungicide application, and avoiding wheat on wheat, producers still see significant challenges in terms of yield reduction, grade reduction, and mycotoxin contamination,” he explains.

When it comes to yield reductions in your crop, Turkington notes that it comes down to at what crop stage the pathogen begins its infection.

“If it’s right close to, or shortly after (head) emergence, right at the start of anthesis, the impact can be quite significant. You are probably looking anywhere from 10 to 30 per cent yield loss, but more importantly, you’ll have a lot of downgrading due to the presence of fusarium damaged kernels in your harvested grain.” (Story continues below player.)

Currently, fungicide timing is recommended starting at 75 per cent head emergence, but Turkington says that is something they are looking at changing.

“The issue with that window is that I think it starts too early. And at that stage, you still have 25 per cent of the head in the boot, which means that 25 per cent of the heads — if you spray at that stage — are not protected at all,” he emphasizes. “I think the key is ensuring that you get good coverage on the tissues that you want to protect, so the head tissues themselves. I would be inclined to say don’t be too eager to put on a fungicide, you should wait until you have full head emergence, and then hit that target with good application technology and a good chemical.

Recent research from our neighbours to the south has furthered the research showing the fungicide timing window should potentially be altered.

“If you put it on too early, you might see that your level of efficacy and control is not what you want to see. If you look at some of the recent research out of the United States, actually delaying application is not going to be a negative. In fact, the level of control and reduction in DON can be quite comparable, if not even better, than putting a fungicide on right at the start of anthesis.”

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