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Six Tips to Manage Herbicide Resistant Weeds in Soybeans

January 13, 2017
Agronomic image of herbicide resistant weeds in soybean fields

A herbicide resistance problem doesn’t develop overnight. Usually, it’s the result of high selection pressure put on a weed population over the course of several years. By repeatedly applying the same herbicide or several herbicides that use only a single effective mode of action (MOA), or applying a herbicide at less than a labeled rate, growers can accidentally create that pressure.

The results of herbicide resistance can be extremely costly. In the long run, taking a proactive approach to weed management is the most effective and economical way to tackle this challenge. To help manage herbicide resistant weeds, we recommend the following best management practices:

  1. Plant in a seedbed free of problem weeds, especially where Palmer amaranth is the major issue. In this case, use tillage or chemical burndown with products like Gramoxone® SL 2.0 herbicide (Geography: 100 mile radius (AR, West TN, Bootheel MO).
  2. Use full rates of herbicides with different mechanisms or effective MOA prior to planting and throughout the growing season.
  3. Optimize soybean growth environment with a combination of cultural and management practices that promote healthy vigorous plant growth such as CruiserMaxx® Beans with Vibrance® seed treatment, a combination of separately registered products, and appropriate nutrition.
  4. Overlap residual herbicides from burndown to canopy-closure applications to ensure minimum escapes during the growing season. As demonstrated in the photo below, Boundary® 6.5 EC herbicide pre-emergence provides residual activity with 2 MOA and excellent activity on most problem grass and broadleaf weeds.
  5. Use overlapping residuals by combining glyphosate post-emerge together with a product like Prefix® herbicide that has 2 MOA and is effective on most problem grass and broadleaf weeds.
  6. Use registered formulations of Dicamba, if necessary, at the recommended rate to clean up escapes of weeds like Palmer amaranth before they exceed 2” in height.

An agronomic image showing weed management.

A field in Memphis, TN, treated with Boundary and Prefix (left) compared to a field with only glyphosate (right).

Well-developed resistance management plans help growers protect yield potential and maximize profit, protecting the grower’s bottom line.

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All photos are the property of Syngenta or are used with permission.

©2017 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status. Gramoxone SL 2.0 is a Restricted Use Pesticide. CruiserMaxx Beans with Vibrance is an on-seed application of CruiserMaxx Vibrance alone or with Apron XL. Apron XL®, Boundary®, CruiserMaxx®, Gramoxone®, Prefix®, Vibrance® and the Syngenta logo are registered trademarks of a Syngenta Group Company.