Reducing Errors in Herbicide Applications

As herbicides and combinations of herbicides become more numerous, there are greater chances of errors and off-target chemical drift in herbicide applications. Herbicide tolerant crops have been developed that allow certain non-selective or broad spectrum herbicides to kill weeds without injury to the crop. The use of non-selective herbicides on tolerant crops presents special challenges to insure crops without the trait are protected from accidental mis-applications and off-target movement.

The University of Arkansas Cooperative Service is promoting “Flag the Technology” program.  This program consists of placing color-coded bicycle flags or similar markers at field entrances or other conspicuous locations to indicate the use of different herbicide technologies.  The system, which is gaining popularity in the Midwest, can make a difference between a healthy crop and a damaged or dead one.  Missouri agricultural retailers who make custom applications are beginning to use the system.

When an applicator pulls into a field to make an herbicide application, the flags help to assure them that they have the correct chemical in their tank to match the traits in the field.    Also, they might be able to look at fields across the road, and if there are different colored flags in nearby fields, then applicators may reconsider before spraying in windy conditions.

Preferred flag size is a minimum 11in X 17in for maximum visibility on a 8ft X ¼ in fiberglass pole.


1. RED flags signify conventional varieties with no herbicide technology traits.  Extreme caution.

2. WHITE represents the Roundup Ready Technology that is tolerant to glyphosate herbicide.

3. BRIGHT GREEN indicates the Liberty Link Technology.  This technology is tolerant to glufosinate (Ignite) herbicide

4. BRIGHT YELLOW is the color chosen for Clearfield technology.  This technology is tolerant to imazethapyr (Newpath) and imazamox (Beyond).

5. TEAL is the color that indicates tolerance to both 2,4D and FOP (Accase) herbicides or the Enlist® technology. The white stripes indicattolerance to glyphosate. For Enlist cotton and soybean fields, a green flag should be added to denote tolerance to glufosinate (Liberty).

6. BLACK indicates tolerance to dicamba herbicide or Xtend®. The black and white checks indicate tolerance to both dicamba and glyphosate (Roundup). A green flag should be added for cotton to denote glufosinate (Liberty) tolerance.

The flag method is gaining significance because of the crops with new herbicide-resistance traits entering the marketplace. Farmers and agricultural retailers who make herbicide applications to large acreages, deal with multiple employees and apply multiple products will find the  program of great value.

Source: Joni Harper, Agronomy Specialist