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Top 10 weed management practices

Herbicide resistant weeds are no longer a novelty, they’re the norm

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Top 10 weed management practices

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Photo: Lisa Guenther

Hugh Beckie, a research scientist with Agriculture and Agri-Food Canada, said it’s a challenge to get farmers to implement herbicide-resistance best management practices (BMP) because growers are diverse, and one size doesn’t fit all. But Beckie has found that growers who use BMPs tend to have less herbicide resistance.

So, in the spirit of David Letterman’s top-10 lists, Beckie presented his top-10 BMPs.

Related: VIDEO: Herbicide resistance spreading in Western Canada

10. Sound record-keeping

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Photo: File

Include weed populations in each field, not just herbicide use.

Related: We need to get our herbicide resistance response right

9. Strategic tillage

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Researchers found that growers who included some tillage, even infrequently, had less resistance. Beckie said there is a place for some tillage, especially with weeds such as kochia. Vertical tillage and rotary hoes are two options.

Related: Keeping volunteer canola out of soybeans

8. Site-specific weed management

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Photo: Charles Geddes

Manage resistant patches early, before they spread through the field.

Related: Crop Advisor’s Casebook: Cleaver in canola a mystery

7. Weed sanitation of equipment

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Farmers with weed infested fields should begin with their cleanest field and work their way over to the most heavily-infested. Then thoroughly clean equipment once the worst field is complete.

Related: Waterhemp knocking at Canada’s door

6. Don’t use wheat-selective in-crop herbicides every year on wild oats

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Wild oat uses the same enzyme system to break down herbicide as wheat. Using wheat-selective herbicides repeatedly will select for resistant wild oats.

Related: VIDEO: Canada ranks high in global herbicide resistance ratings

5. Rotate herbicide groups

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Every time a crop is sprayed, selection pressure is applied to that population. Spray often enough with the same chemistry, and soon the population of non-resistant weeds will be wiped out, with all that is left are the resistant weeds.

Related: VIDEO: The potential for post-harvest weed control in Western Canada

4. Use tank mixes

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Photo: iStock

Growers need to closely following their herbicides’ label directions on timing, specific controlled weeds and correct rates. Deviating from this may reduce herbicide effectiveness and increase weed seeds going back into the soil.

Related: Heading off Group 2-resistant weeds

3. Pre- and post-herbicide scouting

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Producers need to watch for weed patches and any performance issues that look suspicious, then mark those spots and use various methods to contain the weeds from spreading further.

Related: Weed control in a dry summer

2. Select competitive crops and implement practices that promote competitiveness

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Good agronomy, such as higher seeding rates and the 4Rs of fertilizer application, help establish a competitive plant stand.

Related: Multi-species cover crops help control weeds

1. Crop rotation

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Photo: Allan Dawson

Overall, Western Canada does have relatively diverse crop rotations, despite canola being grown frequently. “And I think that has kept the lid on resistance in Western Canada, along with some of the other practices.”

Related: Controlling seeds post-harvest

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