Trouble looming if there’s another cool, wet spring

Four to Watch: Increasing disease levels over the last few years could lead to 
big-time outbreaks if the environmental conditions are right

clubroot affected plant
Reading Time: 3 minutes

This much is known.

“We’re not going to have a disease-free year — that’s for sure,” said Michael Harding, a research scientist with Alberta Agriculture and Rural Development.

“The environment will determine how much we see and which pathogens have the ability to cause the most serious issues.”

And just what kind of environment — a.k.a. weather — is Harding hoping for?

“It would be great for us to have a warm, dry spring,” he said.

The opposite has been the case in recent years; conditions that “play into the hand” of root rots, stripe rust, and even ergot, which can start in native grasses and move into cultivated cereals.

On the other hand, some diseases — including a new strain of root rots found this past summer in pea fields — are a greater risk during warmer, drier springs. But overall disease issues should be reduced under those conditions.

The “big three” to watch out for in canola this year are blackleg, sclerotinia, and clubroot.

Michael Harding
Michael Harding photo: Jennifer Blair

“In 2014, the surveillance that was done revealed 383 new cases of clubroot, and there were four new counties or municipalities that joined the ‘clubroot club,’” said Harding.

“In addition to that, there was a new clubroot pathotype that was identified in the Edmonton area that has overcome the resistance in all of our available cultivars. That’s been a big concern.”

That’s the other known — clubroot is going to continue its grim march across the province.

“Clubroot isn’t showing any signs of slowing its movement into new fields. It’s being found in hundreds of new fields every year and in new counties every year, and we’re not seeing the curve level off.”

In cereals, fusarium head blight and stripe rust are starting to emerge as “commonly occurring problems” that producers need to be on guard against.

“Stripe rust has been a disease that we’ve been watching for and seeing significant levels building for the last few years,” said Harding.

“It’s a disease to be on the lookout for and scouting for, especially for producers who aren’t growing resistant cultivars. You need to catch it quick and be ready to intervene with a fungicide.”

Fusarium head blight is “really on the rise” in Alberta, he said, and now it’s moving into areas where it hasn’t been commonly seen.

“Seed-borne levels of fusarium graminearum have reached record highs over the last couple of years — not just in southern Alberta, but in all cereal production areas across the province,” said Harding.

“It’s definitely something for producers to be on the lookout for and to be ready to manage.”

In the past, ergot was a “sporadic issue,” but levels have been steadily increasing.

“The last few years, ergot levels haven’t been dropping back down,” he said. “It has become a real serious problem for some cereal producers because of the downgrading issues that accompany it.”

Root rots are also becoming more widespread, especially in peas.

“The survey that was done in 2014 showed that 88 per cent of 150 pea fields surveyed had some level of root rot in them. And within fields, about 67 per cent of roots had some symptoms on them.”

And a new root rot pathogen will continue to be a problem heading into 2015.

“The main problem in most pea fields is fusarium, but aphanomyces appears to have found its way to Alberta,” he said, adding that the new strain was confirmed in 17 fields in southern Alberta this past year.

For all crop types, conditions in the past several years have been “really conducive” to diseases like root rots, clubroot, and stripe rust, leading to a buildup of spores in the soil.

“We’ve had three or four years in a row where a lot of these diseases have been quite prevalent,” said Harding.

“The higher the disease levels, the more abundant the inoculum is the following season to initiate new infections.”

This type of ramping up could lead to disease outbreaks — or even epidemics — if the environmental conditions are right.

“We certainly don’t need to push any panic buttons, but we do need to be aware that these organisms are out there, and they can take a real serious bite out of the economics of farm operations,” said Harding.

“Being aware and being prepared to deal with these things can really help the bottom line.”

About the author


Jennifer Blair

Jennifer Blair is a Red Deer-based reporter with a post-secondary education in professional writing and nearly 10 years of experience in corporate communications, policy development, and journalism. She's spent half of her career telling stories about an industry she loves for an audience she admires--the farmers who work every day to build a better agriculture industry in Alberta.



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