Be prepared for FHB this growing season

By: Dallas Carpenter

Thanks to the dry conditions across much of the province, the prospect of a fusarium head blight (FHB) outbreak may not be top-of-mind for many Saskatchewan wheat producers.

In spite of the current weather not seeming to favour the development of FHB, FHB cannot be ruled out and producers must be prepared to manage it in 2019. With many crops hitting the heading stage soon, it will be important for producers to have their management strategy in place to minimize FHB infection, with the frequent scouting of fields and consideration of applying fungicide during the optimal timeframe being key elements of an effective management strategy.

Mitchell Japp, Provincial Cereals Specialist with the Saskatchewan Ministry of Agriculture, believes it pays to be prepared for FHB as it is a consistent threat. “Although it was dry in 2017 and 2018, FHB symptoms were present in 26 percent of spring wheat and 53 percent of durum fields included in the 2018 disease survey,” he says. “The severity was low in spring wheat but higher in durum wheat than in 2017. Dry conditions resulted in lower severity and incidence levels than experiences in 2016 or other wet years.

“However, since FHB symptoms were present, we know there will still be inoculum out there. If the conditions are right at the right time, leading up to and during heading/flowering, FHB could still be a problem in 2019.”

FHB can strike quickly and can have a major impact on yield and grade while potentially leading to the development of the mycotoxin deoxynivalenol, or DON, which can impact the export prospects for Canadian wheat. Growing a variety of wheat with good FHB resistance is important to minimize the development of FHB and DON, and according to the Canadian Grain Commission, over 81 percent of Saskatchewan producers now grow CWRS varieties with an intermediate to moderately resistant rating to FHB.

Growing a wheat variety with good resistance and being prepared for the possible application of a fungicide provide the foundation of a good FHB management strategy. “FHB is a challenging disease to manage for because it is a mono-cyclic disease, which means you can’t scout for the disease in advance,” says Barb Ziesman, Provincial Plant Disease Specialist with the Saskatchewan Ministry of Agriculture. “You have to scout for the conditions that may lead to disease and weigh the risk of disease with the potential value of the crop.”

Ziesman believes that scouting for conditions favourable to FHB development is worthwhile for producers, even if the weather has been dry. “In 2018, many producers observed that when they walked through their wheat fields, their pants were getting wet,” she says. “That indicates high relative humidity and at least some of those growers opted to spray based on that assessment, even though there was no rain and atmospheric relative humidity was not high enough to trigger a warning from the risk maps.  

“FHB thrives under wet conditions and high humidity may provide enough moisture to drive disease development if the pathogen is present, particularly is moisture is present within the canopy.”

One of the key FHB management tools for producers will be the FHB risk maps, which will be live on the Sask Wheat website in June and July. This year, there will be one map to cover all crops. Adjustments were made to the model last season and the model will be evaluated and adjusted as needed this year, as well.

FHB Management Resources

Sask Wheat Fusarium Risk Map and Resources: http://www.saskwheat.ca/fusarium-resources

Saskatchewan Ministry of Agriculture: www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/crops-and-irrigation/disease/fusarium-head-blight

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