Canola School: The value of a pre-seed scout for weeds


We’ve all experienced those fields where the weeds have gotten out of hand. Sometimes weeds getting away on us is because we didn’t have a great handle on what was out there to begin with.

RongRong Xian, technical service manager with BASF, says scouting before you get into the field with the drill is key. It’s also key to make note of the field history  before you scout — are there any herbicide resistant weeds? Are you seeing reduced efficacy? What are typically the troublesome weeds on the field?

Canola, in it’s early stages — between cotyledon and up to four-leaf stage — isn’t a competitive crop at all, says Xian.

“It’s pretty vulnerable to all the external stress. So, when there’s weeds that showed up early ahead of the emergence of canola, the canola doesn’t have any defence mechanism to really fight for resources, moisture, and nutrients,” she explains. “That’s why you really want to clean up your field before canola seeding.” (Story continues below video)

It’s also important to keep in mind that all weeds don’t respond to herbicides the same way, so you’ll need to identify the amount of broadleaf vs. grassy weeds, and whether they are perennials, winter annuals, or annuals.

Across the Prairies there is a wide spectrum of moisture availability — from too wet to too dry — but for the areas that are drought stricken, eliminating that competition is even more crucial.

“There’s some weeds that you would never expect to pop up, especially in a dry spring. But one example I can think of is kochia. It’s the first thing that usually shows up in the field before anything else,” she explains.

If you are in a field where you are dealing with volunteer canola, Xian recommends a three-layer herbicide approach.

“You go in with the pre-seed herbicides in addition to glyphosate, so that really leverages the multiple modes of action to target not just the challenging weeds, but also run-up that weed spectrum. Later, follow up with an in-crop herbicide application to remove that weed competition for good,” she says.

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