Despite dry weather in 2015, fusarium head blight was found in almost twice as many counties as it was in 2010.
A province-wide survey conducted by provincial scientists detected fusarium graminearum — the pathogen that causes fusarium head blight in cereals — in 22 counties in Alberta, up from 13 counties in the 2010 survey.
While not surprising, it is alarming, said research scientist Michael Harding.
“Fusarium graminearum has been a concern for a lot of producers in Alberta for a while now,” he said. “We found fusarium graminearum in the same counties that we found it in the 2010 survey, but we also found it in some new counties on the eastern side of the province, north of the traditional areas for fusarium graminearum.”
And other parts of the province are at risk.
“We can tell you where we detected it in our random survey, but just because we don’t detect doesn’t mean that it isn’t there,” said Harding.
The 2015 survey showed that incidences of fusarium in southern Alberta are still “much higher” than in the central part of the province, but the disease is moving north.
“We haven’t detected it in the Peace Country in our surveys. That’s not to say the graminearum isn’t there — it’s just to say that we haven’t detected it.”
While it’s too soon to tell if fusarium spread even further in 2016 — the results of this year’s survey are still being compiled — “it would be very surprising if we didn’t see higher levels of fusarium” based on the wetter summer seen in most areas of Alberta.
“2015 was a year where we’d be less likely to find fusarium graminearum,” said Harding. “It was extremely dry during the anthesis period in most parts of the province, which is the window of infection. Because it was so dry at that time, most everyone predicted we’d see much lower levels.
“There was much more fusarium graminearum in Saskatchewan and Manitoba than there was in Alberta, and that’s due in part to the dry conditions that we had in Alberta.”
Both farmers and surveyors reported “quite a few symptoms” in the field this year.
“The prediction is that it would be a year where we would be able to detect it in areas where we didn’t detect it last year, and in the areas where it’s well established, it’s likely to have been more severe,” said Harding.
“That will be borne out as growers start to deliver and have samples evaluated for fusarium-damaged kernels. If they do have a significant amount of fusarium head blight, it will show up in their grain samples and they could be downgraded for it.”
Use all management tools
Fusarium head blight is costing farmers big dollars. Since the early 1990s, when the disease caused its first severe outbreak on the Prairies, estimated losses have ranged between $50 million to $300 million annually in Canada.
“Downgrading is the primary way it takes money out of the pockets of grain producers,” said Harding. “It also reduces yield. Oftentimes, shrunken kernels end up blowing out the back of the combine. They’re not harvested, and when they are, they’re lighter.”
Fusarium produces fungal toxins — called mycotoxins — that can cause death in livestock and humans and create market access issues for Canadian cereals.
And once it’s in the field, fusarium can be “very challenging to manage.”
“That’s one of the reasons that there’s a lot of messaging around avoidance — trying to stave off the advance as best we can for as long as we can,” said Harding. “Once we do get it, there aren’t a lot of great management options.”
But there are some things producers can do to prevent fusarium and reduce its spread — using seed with non-detectible levels of the fusarium pathogen, using disease-tolerant varieties, lengthening crop rotations, not irrigating during the anthesis stage, and applying a fungicide at early anthesis when the infection risk is highest.
Ideally, producers should stack those management tools, said Harding.
“Where fusarium graminearum is well established and is causing significant disease pressure, producers need to be aware that there isn’t just one thing that they can do that’s going to prevent the disease,” he said.
“If you’re growing a tolerant variety and there’s a lot of disease pressure, that’s not enough to completely avoid getting fusarium head blight.”
The 2015 survey shows producers in other areas of the province need to be prepared to manage it once it becomes established.
“Those foundational principles of clean seed, crop rotation, genetics, and fungicides when the risk is high are important for producers to keep in mind,” he said. “But even then, there’s no guarantee that you’ll avoid getting fusarium head blight.”