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Get ready to Flag Your Field

moving sprayers
As spray rigs move from one field to another, operators need to know what crop or technology is available in the field to prevent misapplication.
Flagging fields could help prevent misapplication and drift injury from new herbicide technology.

What started as an idea in Arkansas may be on the verge of exploding across Texas and other states, a program that is both bold and, for some, a little intimidating. But it is being hailed as a possible solution to developing weed problems that threaten to take agriculture back to the dark days of weed wars and yield losses.

Just about any farmer of the last several decades will tell you, agriculture started winning the war on weeds beginning in the 1970s with a few early successes between 1946 through 1964, when some of the first broadleaf weed killers were introduced.

Many remember the days of 2,4-D and atrazine—both the up side and the downside. Seven more herbicide modes of action for corn and soybeans debuted during the golden age of herbicides, especially mid-to-late 1980s and the following decade when GS, EPSP, and ACCase inhibitors were introduced. Before long PPO, ALS and Carotenoid Synthesis inhibitors hit the market, and not long after Roundup Ready soybeans followed in 1996.


For a while it looked as though science had finally helped control if not conquer dreaded weed problems—or not.

It wasn't too many years later that resistance problems started emerging. The hope most held for weed-free fields turned sour, and only in the last few years we have discovered we may be turning full circle in our weed fight as emerging resistant strains of pigweed, waterhemp, marestail and other unfriendly plants find their way around modern technology and threaten to drive us back to old-school weed management.

Researchers and weed scientists soon recognized that we must re-evaluate our management programs. While glyphosate and glufosinate resistance, and eventually triple-stack and quad-track resistance problems started cropping up in recent years, heavier loads of herbicides were applied in various recipes, further complicating resistance problems.

In many ways we have come full circle again. From tilling to no-till and back, to better crop rotation strategies to the return of multiple modes of chemical action, there is no doubt weed problems have become more difficult, worrisome and costly for farmers in recent times.


A new idea offers new hope to resistance problems. As management tools have become more complex, we are realizing herbicide combinations featuring various modes of action may be a better choice than what we have been using. New herbicide combinations coming out include products that are using Dicamba and 2, 4-D that can only be used on crops tolerant to one or the other of those products. More attention is required to issues like drift, sprayer clean-out between different chemicals and even nozzle selection to protect not only your own crops in the field, but also your neighbors’. The new strategy of multiple modes of action seems promising, but not without challenges.

This is how a Flag the Field strategy was developed, and is being promoted by researchers, Extension specialists, university scientists and farmers as a way to regain better control of weeds in the field.

Beginning as early as Apr. 1 (2017), a new mobile app for smart phones and tablets will help farmers and pesticide applicators reduce the potential for misapplication of herbicides to sensitive crops through a Flag the Field program that combines hi-tech and low-tech strategies in what promises to be the best way to turn the corner on the war with weeds.

Ray Smith, Chairman of the Board for the Texas Plant Protection Association (TPPA), says the idea is simple.

"Farmers will be required to target their weed management to the type of crop they are growing in a specific field to prevent applying the wrong mode of action on the wrong crops and to reduce problems associated with drift. Flag the Field is designed to take the guesswork out of new technology by placing either real flags in the field or virtual flags that can spotted by looking at a smart phone or tablet app that will tell not only the farmer but also his neighbor who is participating in the program what kind of herbicide can be used on or near those crops," Smith says.


On the low-tech side of the program, farmers can obtain colored or color-coded flags from their seed retailer or industry representative and place the flags at entry levels to the field. This signals not only the farmer but his neighbors on what kind of mode can be used in that field according to type of crop planted.

For those choosing to use a phone or tablet app, the job is easier. Participating farmers and participating neighbors can view fields on and surrounding their farm or leased property and can see “virtual flags” that relay the same information. How much information a participating farmer wants to share is up to him.

"There has always been a tendency to keep some information to yourself when you farm. We are not always willing to share what we're doing in our fields, and this is partially a barrier we need to overcome with this program. If we can learn to communicate with our neighbors, hopefully we will all be more sensitive to what, when and how we spray our own fields. We begin to recognize the risks for not only our own crops, but also for those of our neighbors," Smith adds.

The idea is to help farmers be more aware and more careful in their spraying schedule, prioritizing the risks of drift, nozzle selection and other variables to ensure the right chemical is used and remains on the right crops.

"This is a win-win for every farmer. It just takes a little cooperation and communication," Smith says.


Smith says after he and others approached Texas A&M Extension representatives about the program the idea grew from a simple flag-in-the-field program to one that could be accessed and used from a smart phone.

"They already had a crop registration program worked out for smart devices, so we were able to work with them in adapting that app to work with this program much the same way. The good news is that while we are concentrating on fields in Texas, Louisiana and places like Arkansas, we can easily see where this could be a “go-to-a-place” app that would work as well just about anywhere, even Brazil and places like that," he says.

Already the app can be downloaded from Texas AgriLife Extension, though it is not fully functional for another two weeks or so. But many have already downloaded it so they can get familiar with how it looks and feels Smith says. But starting around April 1, the app should be fully functional and farmers can begin to register and to log information into the app, including inviting whatever neighbors they desire to also have access to however much information they wish to share.

"Farmers will have a choice of what information to share and what not to share, and who to share it with, so they maintain security on their farms and keep things private they prefer to keep to themselves. The idea is to promote a better understanding of how we can all work together to combat this weed resistance problem with the intent of managing and controlling weeds better," Smith says.

He said once the app is fully functional he will release a statement of instructions to Farm Press, other support organizations and farmers to help them understand and be able to operate the app and the program easily and effectively.


The following are flag colors and uses:

  • White — Technology is tolerant to glyphosate herbicides.
  • Green — Tolerant to glufosinate herbicide, Liberty.
  • Yellow — Clearfield rice, sunflowers, wheat and canola, which are tolerant to imidazolinone herbicides.
  •  Teal — Tolerant to both 2, 4-D and FOP (ACCase) herbicides, or Enlist technology. The white stripes indicate tolerance to glyphosate, Roundup. For Enlist cotton traits and soybean fields, a green flag should be added to denote tolerance to glufosinate herbicide (Liberty).
  • Black and white checkered —Tolerant to dicamba, Engenia and XtendiMax, and glyphosate, Roundup Ready Xtend. 1/2
  • Red — Extreme caution required. Indicates conventional crops with no herbicide tolerant traits as well as sensitive production areas such as vegetables, vineyards, apiaries and organic production.

Download the Texas A&M Extension 'Flag the Field' app for iOS at iTunes (

Download the Texas A&M Extension Flag the Field app for Android at Google Play Store.

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