Ontario farmers continue to wage war with fusarium head blight (FHB). The battle is far from over, as evidenced by the disease’s impact on the provincial wheat crop in 2013. But with an ever-expanding management toolbox farmers are now in a much better position to defend their crops, says University of Guelph Associate Professor David Hooker.
Vivid memories of 1996, when only 10% of the wheat crop made milling grade, are still burned in growers’ minds; as are images of 2013 when weather conditions helped FHB make a significant comeback, affecting about 50% of the crop.
“We still have wheat that can be infected with fusarium if it’s mismanaged and given the right weather conditions,” says Hooker. “But the risk of infection and downgrading for higher amounts of toxin is much lower today if the disease is properly managed.”
In this episode of Wheat School, Hooker shares his thoughts on the role genetics, fungicides and other management strategies have played in helping farmers better manage FHB. He even offers a top ten list of tools that have enabled farmers to gain an upper hand on the disease.
At the top of Hooker’s list are resistant varieties. “We don’t have complete resistance yet, but we do have a lot more varieties that are moderately resistant compared to those that are highly susceptible,” says Hooker. “Fifteen years ago most of our varieties were highly susceptible, and now very few are highly susceptible to the disease.”
The availability of effective fungicides has also given farmers an edge, says Hooker. “They don’t give 100% control of fusarium, but it’s a very important management strategy to use fungicides, especially when the genetics are a little bit on the weak side or when the weather is favourable to disease development.”
Research shows that genetics and fungicides actually combine for an effective one-two punch to give farmers some knockout power. In 2013, when weather conditions were very favourable for FHB infection, Hooker says the Ontario Cereal Crops Committee trials show that highly susceptible varieties with no fungicide had an average Deoxynivalenol mycotoxin (DON) level of 4.7 ppm. In comparison, higher levels of management – moderately resistant varieties with a fungicide application – had DON less that 0.7 ppm. “That’s about one-sixth of the toxin,” says Hooker.
The DON cast prediction model, better fungicide timing and sprayer application methods also play a role in the success story, but farmers need to remain vigilant and follow best management practices to keep FHB at bay.
“Every year in Ontario, we still have pockets that have higher levels of fusarium we should consider unacceptable,” adds Hooker. “We still have to manage the disease. It’s still around. It just needs the right weather conditions. If a grower relies on susceptible varieties and there’s a lack of management it could create an epidemic in a particular field if the pathogen is available.”