Tips for managing fall weeds in Ontario

Oct 05, 2017

OMAFRA lists three ways to utilize your window for herbicide application

By Kaitlynn Anderson

Staff Reporter

Farms.com

In this week’s field crop report, OMAFRA offered a few tips for farmers to use their herbicide application window to the best of their advantage.

First, farmers should “choose the most effective products, rate and tank mixes for the perennial weed that you are targeting,” according to the field crop team.

A team in the department of plant agriculture at the University of Guelph provided the following table in the report, which outlines the “best herbicide option for each targeted perennial plant”:

Perennial Plant	Product(s)	Product Rate	Average Control (Range in control)
Dandelion	Glyphosate (540 g/L)	1.34 L/ac	90% (84 - 100%)
Perennial sow-thistle	Glyphosate (540 g/L)	1 L/ac	90% (85 – 100%)
Canada thistle	Glyphosate (540 g/L)	1.34 L/ac	90% (85 – 100%)
Alfalfa	Glyphosate (540 g/L)+ 2,4-D Ester (564 g/L)	0.67 L/ac + 0.5 L/ac	95% (90 – 100%)
Wild carrot	Glyphosate (540 g/L)	1.34 L/ac	82% (49 – 100%)
Burdock	Glyphosate (540 g/L)	1.34 L/ac	90% (85 – 100%)
Red clover	Glyphosate (540 g/L)+ Distinct	0.67 L/ac + 200 g/ac	99% (96 - 100%)

Second, farmers may want to consider applying herbicides in the late morning or during the middle of the day, when air temperatures are above eight degrees Celsius for at least two hours following application. This ensures that the “targeted plant is taking up glyphosate during the heat of the day,” according to the OMAFRA team.

Third, the team recommends waiting two to three days after a frost event to evaluate weed growth.

“Depending on how cold (temperatures were), the plants may be damaged and no longer growing,” said Dale Cowan, a senior agronomist with AGRIS and Wanstead Cooperatives. “Plants need to be actively growing to take in herbicide.”

By waiting for the plants to resume growth before applying herbicide, the weeds will then be able to take up the product, he said.

If the plant that farmers are wishing to control looks fine, then they may want to consider resuming herbicide application once the temperatures have again risen above eight degrees Celsius.

The team also encourages producers to wait 72 hours to till the soil after a herbicide application.

“The longer that you can wait after application before making a tillage pass, the more the herbicide will translocate within the plant and do a more effective job controlling the species,” stated the report.

Learn more about weed management in the Farms.com field guide.

Photo: La Corivo / iStock / Getty Images Plus

Video: Seeing the Whole Season: How Continuous Crop Modeling Is Changing Breeding

Plant breeding has long been shaped by snapshots. A walk through a plot. A single set of notes. A yield check at the end of the season. But crops do not grow in moments. They change every day.

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This conversation explores:

• What continuous crop modeling is and how it works

• Why traditional field observations fall short over a full growing season

• How scale and repeated measurement change breeding decisions

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• Why data, not hardware, is driving the next shift in breeding innovation As data-driven breeding moves from research into real-world programs, this discussion offers a clear look at how seeing the whole season is reshaping value for breeders, seed companies, and farmers, and why this may be only the beginning.