Pre-seed burnoff
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Weed competition is costly
Pre-seed burnoff
Weeds that emerge before the crop can be highly damaging to crop yield potential because they out-compete the crop for moisture, nutrients and sunlight. When the crop emerges, all early weeds need to be dead.
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Weed considerations for early May
Pre-seed burnoff
For best results, spray winter annuals when they’re small. They’ll be growing fast this week.
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Tank mix options for pre-seed burnoff
Pre-seed burnoff
Tank mixing is an important step in preventing herbicide resistance in weeds, and the pre-seed window is a good opportunity to use a tank mix rather than just straight glyphosate. Tank mix options for glyphosate ahead of canola are:
–bromoxynil
–Aim/CleanStart (carfentrazone)
–clomazone
–Conquer (bromoxynil and carfentrazone) -
Why add a tank mix to pre-seed glyphosate?
Pre-seed burnoff
Of all the glyphosate applied in the pre-seed window in Western Canada in 2017, 73% was applied alone. Only 27% was tank mixed. That’s according to data Monsanto presented at meetings this winter. Tank mixing multiple modes of action is generally considered one of the best ways to avoid herbicide-resistance, so we want to see that tank-mixing number grow.
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Seeding is two weeks away. Should I spray now?
Pre-seed burnoff
Even if seeding is two or three weeks away, a pre-seed burnoff now could keep these weeds from getting too big to control. We have reports of gigantic winter annuals in fields where they haven’t been sprayed.
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Seed first or spray weeds? A situation
Pre-seed burnoff
A farmer is seeding Roundup Ready canola and the field has a lot of winter wheat volunteers and some perennials. Is the farmer better to seed or spray first?
Answer: In this situation, with Roundup Ready canola being able to take a glyphosate application at any time up to the 6-leaf stage, the farmer may want to take advantage of good seeding conditions and seed, then spray as soon as possible after seeding. Reasons…. -
Pre-seed volunteer canola control: Before canola, before other crops
Pre-seed burnoff
Volunteer canola is a weed and competes with the crop for nutrients and water and sunlight. Volunteers in a canola crop do not make a positive contribution to yield. Growers also have other reasons to get rid of them: Volunteers do not have seed treatment, so they can introduce seedling diseases and increase flea beetle pressure. Also, volunteers in non canola years provide a host for blackleg, clubroot and insects, reducing the effectiveness of crop rotation for managing these issues.
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Spraying in the post-seeding, pre-emergence window
Pre-seed burnoff
If choosing to seed before spraying, weeds present will have a minimum five days — usually more — before the crop emerges. These weeds can advance very quickly in good conditions, which is why growers who seed before spraying may choose to apply in the narrow post-seeding pre-emergence window.
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Weed management timing — scenarios
Pre-seed burnoff
Early weed control is preferred because nutrient and moisture taken up by weeds means less for the crop. Weeds emerging before the crop also compete for sunlight, which is an issue if those weeds canopy over the crop. Ideally, growers want crop emerging in a clean field so it can get ahead of the weed competition. That is why pre-seed and early in-crop control are so valuable.
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Weeds growing strong again
Pre-seed burnoff
Growers will be eager to seed with the return of warm weather but early weed control also remains a priority — especially for fields that have not received any yet. Spraying those fields now and seeding three days later will have an economic benefit given that weed competition remains a major factor in crop yield potential.