A new management tool is available to help Saskatchewan producers assess fusarium head blight risk and decide how to manage it.
Faye Dokken-Bouchard, the provincial government’s plant disease specialist, unveiled risk management maps at the Saskatchewan Wheat Development Commission semi-annual meeting held during Canada’s Farm Progress Show.
She said the maps will be updated daily, so it’s important producers check them often, particularly as their crops get closer to flowering and the time of potential infection.
Dokken-Bouchard said there are steps to take before using the new maps. Producers need to first determine which pathogen might be present and whether it’s established in a region or a field.
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“I think it’s safe to say that fusarium is prevalent in the province, but it might be not as bad an issue in certain fields,” she said.
Producers should consider whether wheat grown in a particular field was downgraded before and what the seed tests showed.
Seed containing more than five percent fusarium graminearum or more than 10 percent of other fusarium types should be treated.
Fusarium found on seed is an indication that the disease was at least in the field. It might not have caused downgrading but could have infected the seed, she said.
Root rot in other crops such as peas and canola is another indication that fusarium might have been present.
“Fusarium is a type of pathogen that can act as a saprophyte and is able to feed on dead material, or it can be a pathogen on other crops causing root rot,” said Dokken-Bouchard.
“It might not be fusarium graminearum.”
Surveys in Saskatchewan last year found that fusarium graminearum was the dominant pathogen for the first time ever.
“The severity took a big jump last year, especially for our durum,” she said.
The second step is to stage the crop to estimate when it will be flowering and how evenly that flowering is occurring. Seeding date and an estimate of growing degree days can help narrow down a date.
“Try to get the best idea of when 75 percent of heads on the main stem will be fully emerged,” she said.
The third step is to watch the weather and use the new fusarium head blight risk maps.
The maps began as a project of the Pest Management Centre and Canadian Wheat Board several years ago. They were validated using actual field tests and survey data, said Dokken-Bouchard.
However, changes at CWB ended the involvement of its agronomists. Weather Innovations Consulting stepped in, and the Saskatchewan Wheat Development Commission committed to getting the maps up and running, she said.
About 420 weather stations gather daily data to update the maps and help producers make their decisions.
Producers can go to the online map, select the date of full head emergence and see the risk. The maps offer a five-day outlook from the date selected.
It’s important to select the right map, as the tool is available for both winter wheat and spring wheat.
It’s also important to check daily because weather will change the risk.
“If we have at least 12 hours of precipitation or high humidity, the spores will germinate and can cause infection,” Dokken-Bouchard said.
“As well, temperatures ranging from 16 to 30 degrees (increase risk), but the higher temperatures are really favourable for fusarium graminearum.”
Green on the maps indicates the lowest risk, orange is moderate and red is high.
She cautioned producers to not just rely on the risk maps.
“If you know what your risk levels are, you still want to look at the crop itself and see how bountiful that crop is going to be at the end of the day because your yield is what’s going to pay for your fungicide application,” she said.
Producers can determine an estimated net return by multiplying estimated yield by estimated savings from fungicide application and the selling price for the crop, less the fungicide costs.
“If you feel you have a higher risk and you’re in the positive in terms of net returns, then your application will pay,” said Dokken-Bouchard.
Producers who decide to spray should consider recommendations for getting the best coverage, which includes angling nozzles forward at greater angles and using coarse sprays and a low boom. Slow speeds are usually recommended, but Dokken-Bouchard said research is now showing that fast travel speeds are fine for vertical targets.
However, she said there are no guarantees, even if everything is timed perfectly. The fungicides registered for fusarium head blight can protect and suppress but not cure the disease.
Commission chair Bill Gehl said producers should also use resistant varieties and practice good rotation.
Durum crops also need protection, he added, but there is a way to go on that front.
For more information, visit www.saskwheatcommission.com/producer-info/fusarium-risk-assessment-map and links to the agriculture ministry’s fact sheets on the pathogen and disease.
karen.briere@producer.com
