Production Blog

Today's herbicide trade names can be challenging enough to pronounce. What's more important is keeping track of what actives and sites of actions those names represent.

There's a free resource to help. The Herbicide Classification Chart from Take Action (https://iwilltakeaction.com/…) groups herbicides and herbicide premixes by their modes of action. This helps you in selecting herbicides to maintain greater diversity in herbicide use and rotate among effective herbicides with different sites of action to delay the development of herbicide resistance.

Sponsored by the United Soybean Board, the chart has recently been updated. The chart was created and is maintained by Michigan State University weed scientist Christy Sprague and has two important sections:

-- A color-coded chart Mode of Action chart, listing every herbicide site of action group and:

1: The number of resistant weed species to that site of action.

2: Active ingredients within that site of action.

3: Examples of branded commercial products containing each active ingredient.

-- A Premix Herbicide Product chart, which lists commercially available premix products and:

1: The active ingredients in each premix.

2: The trade name of each active ingredient.

3: The site of action groups for each premix.

SPRAY BY THE NUMBERS

The site-of-action group numbers listed in the chart correspond to numbers on every herbicide label. It's part of a system developed by the Weed Science Society of America (WSSA). Premixes containing more than one site of action will have multiple numbers listed. The numbering system makes it easier to see the sites of action in many of these products are the same.

It's still important to know and understand the activity of the individual herbicides on weeds present in the field to make sure the product has good activity on the target weeds. For example, a Group 2 herbicide (ALS inhibitors such as Classic and Pursuit) would do little to control waterhemp, since most waterhemp is resistant to these herbicides. A Group 15 herbicide (very long fatty chain/VLCFA inhibitors such as Dual II Magnum and Outlook) would provide little control of giant ragweed or other large-seeded broadleaves due to an inherent poor activity on these weeds.

ONLINE OR ORDER

The chart is a powerful tool for farmers who are facing a growing epidemic of weeds with resistance to one or more herbicide sites of action. The chart can help producers create a herbicide program that incorporates multiple herbicide sites of action within tank mixes and across seasons.

Thanks to the USB's sponsorship of Take Action, the Herbicide Classification chart is available online or for complimentary print orders, up to a certain amount.

Visit the Take Action website resources page (https://iwilltakeaction.com/…) to order or place orders here: https://docs.google.com/….

GROW is a public weed management network managing Take Action's outreach efforts. Learn more about the group's efforts to fight herbicide resistant weeds here: https://growiwm.org/…

Pamela Smith can be reached at pamela.smith@dtn.com

Follow her on social media platform X @PamSmithDTN

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