Field scouting needs to be the first step in deciding whether a pre-seed burnoff is warranted in canola fields this spring, says Arvel Lawson, program manager for crop production with the Canola Council of Canada.

“The burnoff decision is tricky this year since cool conditions have limited weed growth in many areas,” says Lawson. “However, growers need to make sure to get down on their hands and knees to scout, since many seedlings may be just poking through the ground”.

Canola plants are not very competitive when they are small and weeds that emerge before or with a canola crop will cause greater yield losses than weeds that emerge after the crop is established at approximately the 4- to 6-leaf stage. The purpose of a pre-seed burnoff is to protect a young canola crop from yield losses that result from early season weed competition for moisture and nutrients.

For example, average yield increases of 15% have been observed when comparing a pre-seed burn-off treatment to a no burn-off treatment in direct seeding situations.

In fields where weed pressure does warrant a pre-seed burnoff, remember that glyphosate is a systemic herbicide that requires time to work for maximum control. Formulation and target weeds must be considered when deciding on the time required between application and disturbance from tillage or seeding. Additionally, with temperatures getting close to or dipping slightly below zero at night in some areas, Lawson recommends only spraying glyphosate after temperatures have warmed the following day. A hard frost will require a longer recovery time as plants must be assessed for new growth before applying the herbicide. Weeds must be actively growing to ensure herbicide uptake and maximum kill.

If volunteer canola is a target species in a field, the only option before canola is a pre-seed application of glyphosate and carfentrazone. This product will control all types of volunteer canola if used at the proper stage (1- to 3-leaf). Light rates of 2-4,D or MCPA are not recommended to control volunteer canola or other hard to control winter annuals prior to canola since this is not a registered use and may result in herbicide injury to the crop.

In fields with minimal weed growth, growers may want to consider using a post-seed, pre-emergent strategy. Post-seeding, pre-emergent applications of glyphosate can be effective when well managed. “Be aware of the risk of injury to an emerging canola crop with this approach. With some herbicide tolerant systems, the application will have to occur before the crop emerges,” says Lawson.

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Media may contact:

Arvel Lawson

Program Manager for Crop Production

Canola Council of Canada

204-982-2124

For more information in your area, contact:

Derwyn Hammond, Manitoba Region, 204-729-9011

Jim Bessel, North Central and North Eastern Saskatchewan, 306-373-6771

Tiffany Gutzke, Eastern Saskatchewan, 306-231-3663

Doug Moisey, East Central Alberta and Northwestern Saskatchewan, 780-645-9205

Matthew Stanford, Southern Alberta and Southwestern Saskatchewan, 403-345-4852

John Mayko, West Central Alberta, 780-764-2593

Erin Brock, Peace Region, 780-568-3326

This media release is supported regionally by:

Alberta Canola Producers Commission; Saskatchewan Canola Development Commission; Manitoba Canola Growers Association; Canola Council of Canada; Peace River Agriculture Development Fund; B.C. Ministry of Agriculture & Lands.