Why Fall Weed Control Matters

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How to choose the product that is right for your farm.

With smaller weeds and a lack of nighttime freezes, a fall herbicide spray offers improved herbicide efficacy, reduced weed competition and better uptake of nutrients and water.

Kevin Cochrane, Corteva Agriscience territory manager in the Pacific Northwest, illustrates his best-case scenario for fall weed control in winter wheat: An early September planting is followed by the emergence of a healthy stand of wheat and then, with any luck, a good rain.

“When the wheat comes up well, so does the cheatgrass,” Cochrane says. “A herbicide application made four to six weeks after planting will deliver maximum efficacy against these small weeds, primarily cheatgrass.”

Fall herbicide selection is driven by weed presence, especially in wet fall conditions. And with the cereals herbicide portfolio offered by Corteva Agriscience, wheat growers have a plethora of options for their fall herbicide program.

To fight annual grasses present in fall fields, Cochrane often recommends PowerFlex® HL herbicide if broadleaf weed control is not paramount. PowerFlex HL is also an appropriate option if a crop rotation is planned with a crop such as canola or potatoes.

OpenSky® herbicide and Tarzec herbicide also will control annual grasses, and they will deliver more bang for your buck if broadleaf weeds are present. 

“OpenSky shines when prickly lettuce, marestail or kochia are the targeted weed species,” Cochrane says. “OpenSky also offers friendly plant-back options for crop rotation, allowing for most crops to be rotated within 10 months or less. And growers have flexibility in package size options, which is especially convenient for larger farming operations.”

With Tarzec, he says, the best fit may be found with those dryland production areas requiring control of Russian thistle or mustards. 

When a fall spray is part of a proactive burndown program designed to begin the spring season with a clean seedbed, Cochrane recommends including Quelex® herbicide in the tank to control broadleaf weeds. “This is a great option if you are in a no-till or minimum-till production system, or the field being treated has been fallow for the previous season or even for the year,” he says.

Resistance management should also be considered when choosing a fall herbicide program. “Glyphosate has been included in burndown treatments for 20 years or more. Now, marestail, kochia and prickly lettuce all have some measure of tolerance to glyphosate,” Cochrane says. “That’s where the Arylex active in Quelex really shines. A tank mix of glyphosate plus Quelex herbicide will control resistant broadleaf weeds and help manage resistance development.”

Ask your local Corteva Agriscience representative for more information about the benefits of the Corteva Agriscience™ portfolio of cereals herbicides.

™ ® Trademarks of Corteva Agriscience and its affiliated companies. OpenSky, PowerFlex® HL, Quelex® and Tarzec are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Arylex® is a registered active ingredient. Always read and follow label directions.