Crop Scene Investigation: Late-Flowering Canola

Wednesday, March 22, 2023

By Stacy Berry

In the summer of 2022, producers across the Prairies witnessed a rare event which left many questions unanswered, and, as Dale Litke, a farmer near Crossfield, Alta., says, "the answers … left more questions."

What was this mysterious event?

Canola had been seeded as normal and on schedule. It had emerged well enough, with some appreciated early-season moisture. Early spring was a bit cooler than desired, but again, nothing wildly out of the ordinary. And yet, mid-July rolled around, and many farmers' canola was simply … not flowering.

In a normal year, "typically, by the last week of June canola has begun to bolt, and by (mid) July, fields are in full flower," explains Alex Shuttleworth, a Pioneer Hi-Bred sales representative near Airdrie, Alta.

Last year, "canola grew to the four-leaf/bolting stage, and then just sat there. No flowers. When things finally did start to bolt and flower, buds on the main stem were malformed, and there was abortion of the first stems and buds."

Litke, who has been actively farming for over 15 years, saw the same symptoms.

"Canola seeding was completed on schedule, emergence was good – albeit not perfect. Ample moisture in June allowed the canola crops to develop at a normal rate. Into early July is when the budding and flowering issues became evident."

This made for a strange scene for farmers and agronomists. All over south and central Alberta, "fields that should have been bright yellow by mid-July continued to fail at producing flowers," explains Litke.

Possibilities of what was going wrong flew around on Twitter, other social media platforms, and at meetings conducted with the Canola Council of Canada (CCC).

Shuttleworth initially assumed "the problem was due to the lack of heat we had last spring. June had been exceptionally cold in my area." Except, the problems were widespread, and cool temperatures were not experienced across the entire area.

Litke recalls seeing "similar symptoms in 2015, followed by a localized frost in early July but … there'd been no sub-zero temperatures in 2022."

Some producers speculated about herbicide residues and fertility issues, as well as the possibility of insect feeding, as relatively high insect counts had been seen.

An observation that Litke saw on his farm and neighbouring fields was "the fields located on the south and west sides of trees or other sheltered areas seemed to be affected less severely and flowered more 'normally.'" In many minds, this opened the idea of a wind-borne disease.

By July 11, all these possibilities were ruled out.

The CCC then released an explanation for this strange event: hormone imbalance caused by environmental stress.

Shortly afterward, "the plants had recovered from the aborted buds and produced substantial side branching that resulted in 'full bloom' crops," explains Litke.

In August, farmers got the warmth they had hoped for earlier, but unfortunately little to no moisture followed. In fact, August 2022 was ranked as the fifth-hottest month on record around the Calgary area.

The continued dry and warm weather "caused the crop to suffer and mature much earlier than anticipated," says Litke. "The end result was a very underwhelming canola yield."

It's difficult to calculate how much yield was lost due to the flowering delay, versus how much yield was lost due to the lack of moisture through July and August.

Shuttleworth says "it can be reasonably assumed that there was a yield loss because of this. It's hard to know how much, because every field showed these symptoms to some degree." On top of that, the plants "wasted two weeks of soil moisture" during the time buds and flowers weren't forming but should have been, explains Litke.

This was an unusual occurrence for Shuttleworth, but she plans to take the experience forward. "Last year showed that sometimes the best thing to do is have patience."

However, Shuttleworth doesn't want to suggest that the best course of action is to always turn a blind eye to your crop. "This issue (was resolved by) allowing canola to grow through its hormonal imbalance, (but) other issues in the future may not be so easily resolved. It is important to develop good relationships with your local seed sellers, agronomists, and peers to know what else is going on in your area to grow the best crop that you can."

Litke still has questions. "Which stressors were to blame? What potential solutions are there? Should we be prepared to see this next year?"

This is something that most producers have never seen before, and unfortunately, no one knows what new challenges might present themselves in 2023.

Regardless, Litke and his fellow farmers will continue preparing for another growing season, and Litke is hopeful that given time, "some can be found." BF