Tis the season for disease scouting

With harvest underway, canola growers are reminded to look for signs of blackleg, clubroot and sclerotinia

Lacombe, Alta. — Canola growers ready to swath should watch for abnormalities in the field — diseases like blackleg, clubroot or sclerotinia could be rampant, say agronomists.

In fact, now is the best time to be on the lookout, according to Clint Jurke, agronomy director with the Canola Council of Canada.

“Swathing is your prime time,” Jurke said during a Canolapalooza tour near Lacombe on Aug. 29. “It’s really important to do it because you need to know whether or not you are successful at actually managing these diseases.”

Scouting will also give growers a sense of how to manage crops next year, and help determine when they should grow canola again.

“Is it going to be a two-year rotation, three or four?” said Dan Orchard, an agronomist with the Canola Council of Canada, who represents the northern Alberta region. “It’ll help you understand what variety to choose and, more so, choose when you’ll grow canola next.”

During the tour, farmers were told what to look for and what to do when they encounter diseases during harvest, with many farmers still having a ways to go before crop is in the bin.

Agronomists first discussed blackleg, which is caused by fungus and blackens the core of crop where the stem meets the root.

When swathing, producers can locate blackleg by looking for crops that seem browner than the others, and ones that have kinked over, Jurke said.

“If you see this, now is the time to get off the swather and pull those plants out of the ground and determine which diseases you’re dealing with,” he said.

“For blackleg, it’s good to have a pair of sheers and cut through that base part of the stem.”

As well, farmers should look for clubroot.

The disease, which produces club-like galls at the roots, was recently discovered in the Peace region. It’s spreading so fast producers are having a hard time keeping up, Orchard said.

“Roughly, it’s spreading at a rate of 30 kilometres per year, and we’re only managing it at 20 kilometres per year,” he said.

“We have to be ahead of it, not behind it.”

However, both clubroot and blackleg can be effectively managed by growing resistant varieties and having longer crop rotations.

“Scouting and keeping in touch with your crop is your front-line defence,” Orchard said. “If you don’t see clubroot, it can really ramp up.”

Others ways producers can help stop the spread of clubroot include minimizing the movement of soil, cleaning equipment thoroughly, and reducing tillage.

But another big disease to watch for is sclerotinia, which causes stem rot in canola.

Although the disease better flourishes in wet environments — which largely isn’t the case this year — it’s always wise for producers to spray fungicide, said Keith Gabert, also an agronomy specialist with the Canola Council of Canada representing south central Alberta.

“Pretty much spray every year,” he said. “It can rob yield easily.”

And like clubroot or blackleg, determining the amount of scler-otinia on the field can give farmers an idea on how to manage operations next year.

“If you had a real wreck in the field, I would extend that rotation,” he said.

“There are good genetics on the market where they’re not as prone to sclerotinia, but that’s not the same as having genetic intolerance.”

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