7 Ways U.S. Farmers Can Delay Herbicide Weed Resistance

Nick Seibert

May 24, 2023

The number of herbicide resistant weeds continues to grow every year. As of May 2023, the U.S. has 131 unique herbicide resistant weeds and Canada has 55. (1)

To proactively delay resistant weed development, farmers should prioritize creating and implementing a weed resistance management strategy across every acre they plan to plant. Here are seven considerations to incorporate into such a strategy. 

1. Use Herbicide Group Numbers Strategically

Each herbicide group number corresponds to a site of action of an active ingredient. When multiple herbicide groups are applied to control a targeted weed, the weed is less likely to escape a spraying, as it must tolerate many different functional disruptions. (2)

An example of this would be a weed in your area that is known to resist both glyphosate (Group 9) and ALS inhibitor (Group 2) active ingredients. To effectively address the weed pressure, you could apply herbicides from other groups such as GCS Metola Plus 8EC (Group 15) and Willowood Sulfen 4SC (Group 14).

For more details on herbicide groups, see this chart from the United Soybean Board. 

2. Know Adjuvant Requirements

Proper adjuvants can increase the efficacy of your burndown and preemergence herbicides. Consult your label to see which adjuvants are required, recommended or a potential option for use. 

Whether you need a surfactant like IN-Zorb ADV, a crop oil like FBN Crop Oil Concentrate, or a drift inhibitor like Miller Mist-Control®, take the time to familiarize yourself with the products that can help you get the most out of your herbicide shot while limiting unintended impacts. 

3. Include Tillage as a Weed Management Tool

By controlling emerged weeds and burying non-germinated seed, tillage can help reduce seed banks as part of an integrated weed management program with herbicide applications. (3)

4. Enhance the Crop Canopy

Changing planting and fertilizer strategies through experimentation with narrower rows and banding fertilizer could hasten the growth of a crop canopy, shading out competitive weeds.

5. Clean Your Equipment 

Avoid spreading weed seeds by cleaning equipment before leaving each field. Plus, the work that you do to control troublesome weeds in the fence rows adjacent to your fields will also reduce the spread of weeds.

6. Rotate Crops

In addition to improving soil health and increasing crop yields, crop rotation can also help break weed cycles. Rotating crops, including row crops, small grains, and cover crops, on a regular basis can prevent certain weeds from becoming dominant.

7. Rotate Herbicides

While there are many herbicides labeled to control the same weed species, using the same herbicide year after year may initiate resistance and decrease your ability to control the weeds. Herbicide diversity plays an important role in fighting weed resistance.

Shop For Herbicides 

FBN Direct® offers a diverse product portfolio to provide a wide range of herbicide options for growers like you to develop an integrated weed management strategy.

Top Preemergence Herbicides at FBN®

Herbicide Group

Crop

FBN Product

Group 9

*Preemergence Corn/Soybeans

AgSaver™ Glyphosate 53.8%

Group 10

*Preemergence Corn/Soybeans

Willowood Glufosinate 280SL

Group 15

Corn & Soybeans

GCS Metola Plus 8EC

Group 5

Corn ONLY

Atrazine 4L Value Pick

Group 15, Group 27, Group 5

Corn ONLY

Meto 1.7+Meso 0.22+Atrzn 1.66

Group 14

Soybeans ONLY

Willowood Sulfen 4SC

Group 14, Group 2

Soybeans ONLY

Willowood Sulfen Cloran

*Group 9 Postemergence on Glyphosate-traited crops ONLY

*Group 10 Postemergence Glufosinate-traited crops ONLY


Sources:
  1. https://www.weedscience.org/Pages/GeoChart.aspx

  2. https://crops.extension.iastate.edu/encyclopedia/effectiveness-using-multiple-sites-action-manage-resistance

  3. https://hracglobal.com/prevention-management/best-management-practices


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Nick Seibert

May 24, 2023

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