Weeks of rain and hot, humid weather have put Manitoba crops at serious risk of fusarium head blight infestation.
David Kaminski, Manitoba Agriculture’s manager of farm production extension services in Carman, said although the recent cool weather has improved conditions somewhat, the risk of fusarium ranges from moderate to extreme across the entire province.
“Fusarium risk depends on heat and humidity. For a while there, we were getting those in spades,” he said.
Should July turn hot, moisture in the damp soil could create humid conditions in the crop canopy that might prove favourable for the growth of fusarium graminearum.
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Present in isolated pockets in the province since 1923, the first serious outbreak occurred in 1984. The culmination of several growing seasons with hot, humid conditions, which left a great quantity of spores on crop residues, sparked the first widespread epidemic in 1993.
“I don’t believe that we are going to have a year like 1993,” said Kaminski.
“The reason is that there has been a lot of improvements in resistance in the varieties that are commonly grown.”
In that year, the most common variety grown was Roblin, which was “ultra-susceptible” to fusarium. Now, farmers are planting a more diverse mix of cultivars such as 5602HR, Domain, Barrie and Superb, which offer improved resistance.
Also, the last two years have seen lower levels of infection, which has reduced the quantity of spores on the ground.
“We could still have a pretty serious epidemic, but I would say it’s not yet time for the alarm bells. We’re not projecting anything like 1993,” said
Kaminski.
Fusarium infection can occur at any time when the crop is flowering and the temperature is between 15-30 C with humidity near 100 percent.
It is probably already too late to treat winter wheat, but there may yet be time to suppress the disease on spring wheat.
Hitting fields with preventive fungicides such as Folicur and Proline needs to done within a tight window, when the crop is headed and is about to flower. The critical stage can be three to seven days. After that, it is probably too late, he said.
Andy Tekauz, a senior research scientist at Agriculture Canada’s Cereal Research Centre in Winnipeg, said oats and barley could also be at risk if hot, humid conditions persist.
However, treating barley at current prices with Proline may not be cost effective, he said, and oats have no registered fungicide.
“Everybody is on pins and needles with respect to fusarium right now,” said Tekauz.
Additional moisture this week could send the risk level soaring, from high to extreme in spring wheat, barley and oats.
“At the moment, those crops are on the cusp.”
Myriam Fernandez, a plant pathologist with Agriculture Canada in Swift Current, Sask., said the overall risk of fusarium in Saskatchewan is low.
“It will all depend on what happens in the next couple of weeks,” she said. “It’s a combination of temperature and humidity and the combination hasn’t really been there.”
Saskatchewan hasn’t had a serious fusarium epidemic since 2001, when the disease struck the southeastern corner of the province and isolated pockets in the northeast.
The province’s soil type and environment, especially with regard to humidity, are less favourable for fusarium.
“Our situation is very different from that of Manitoba,” she said.
Paul Laflamme, branch head of Alberta Agriculture’s pest management division, said fusarium has been kept under control in the province.
A survey last year of 740 wheat fields found only three infected in the irrigated areas south of Highway 1, and all of them were at low levels.
“It still isn’t a major problem here in Alberta,” he said.
