A devastating wheat disease is on the rise in Alberta — and spreading quickly.
“Over the past few years, (fusarium) has increased considerably, and it’s fairly prominent now,” said Trevor Blois, disease diagnostician with 20/20 Seed Labs.
“This year, around 16 per cent of samples that are submitted for a fusarium test in Alberta are testing positive. That’s the highest we’ve ever seen.”
But the trend is clear: In 2007, only one per cent of samples sent to his lab tested positive for fusarium, he said. That figure jumped to nine per cent in 2012 and hit 13 per cent for the last crop year.
“It’s been going up considerably,” said Blois, who will be giving a presentation on fusarium’s spread at Agronomy Update 2015 in Lethbridge on Jan. 20.
“With the exception of 2011, when the conditions weren’t conducive to fusarium head blight infections, we’ve seen a really steady increase.”
But the news gets worse — the disease has spread to areas of the province where it’s never been seen before.
“Back in 2007 when we started testing a lot more fusarium samples, it was pretty much restricted to five counties in southern Alberta,” said Blois, adding it’s now becoming common in central and northern Alberta.
“Right now, 57 per cent of counties that we test seed in are testing positive. It’s quite widespread.”
Fusarium head blight can cause “severe economic impacts” in wheat crops, said Blois. Losses in Canada from fusarium head blight have ranged between $50 million and $300 million annually since the early 1990s, when fusarium outbreaks began in Eastern Canada.
“Not only does it impact your yield, it also causes a decrease in the quality of your seed,” said Blois. “You’ve got a lot of shrivelled seeds, and they contain mycotoxins.”
That reduces the value of the crop, and at high levels, the mycotoxins make the grain unfit for both human and animal consumption.
And while Fusarium graminearum is “the big concern” in Alberta, other fusarium species are also on the rise.
“Generally speaking, Fusarium graminearum causes the most severe losses, but we are seeing the highest levels of other fusarium species as well,” said Blois, adding those species can cause seedling blight, root rot, and crown rot in other crops as well.
“Those ones can also produce harmful mycotoxins, and the average sample that comes in has a 6.44 per cent infection of fusarium species, which is quite high.”
This sudden rise in fusarium in Alberta has been caused, in part, by tighter rotations, a shift toward zero-tillage farming, and “a general increase in the inoculum.”
Environmental conditions also need to be right for fusarium to spread, and over the past three growing seasons, they have been.
“High levels of rainfall and high temperatures during the flowering period are important for that infection,” said Blois. “That’s really when the infection takes hold, and unfortunately, we usually do get quite a bit of rainfall during that period.”
An uptick in corn acres has also played a role in spreading the disease.
“Corn is an important part of the life cycle of Fusarium graminearum,” he said. “It will probably survive for a couple of years in the corn stubble, and it can spread to nearby fields that way.”
But the biggest issue is infected seed.
“One of the most important things is testing your seed and ensuring that you’re using clean seed,” said Blois.
“There’s a lot of field-to-field spread and the planting of infected seed. If you plant infected seed, you’re more likely to see an infection occurring.”