15 years of weed control: Launched in 2008, Roundup Ready sugarbeets lightened farmers' loads

The 2023 growing season marks the 15th anniversary of when Roundup Ready seed revolutionized U.S. sugarbeet production.

Before Roundup Ready sugarbeets arrived on the scene, weed control was a constant battle fought with an arsenal of tools that required a great deal of farmers’ time and a lot of laborers.

Weeds were a problem in sugarbeets from the beginning of the crop’s introduction into production, said Mohamed Khan, North Dakota State University Extension assistant director.

“Sugarbeets are a short crop and weeds are tall. They (the weeds) would take advantage of sunlight, moisture and nutrients,” Khan said. Before Khan was appointed assistant director, agriculture and natural resources, in October 2022, he was the NDSU and University of Minnesota Extension sugarbeet specialist, a position he held for 23 years.

The sugarbeet industry began researching herbicide weed control of sugarbeets instead of depending solely on hand pulling and cultivating. The most effective chemical control involved the use of a few different herbicides, because there was no single one that worked well to eliminate the weeds.

Farmers still supplemented the herbicides by hiring laborers to hand pull and hoe the weeds in the sugarbeet fields. The workers also used hoes to thin the beets, which produced many plants from the multigerm seeds planted then.

Brent Baldwin, a fourth generation sugarbeet farmer who grows the crop on Baldwin Farms Inc. near St. Thomas, North Dakota, recalls the amount of labor required during his youth to control redroot pigweed and lambsquarters in the fields of his father, William “Buzz” Baldwin, during the 1970s and 1980s

Ann Bailey / Agweek

“We had to pull weeds and we had a lot of hired labor,” Baldwin said. The hired laborers weeded and thinned the sugarbeets, typically in early June a few weeks after they had emerged, then hoed them again a few weeks later.

Alan Dexter, now a retired NDSU sugarbeet specialist, researched using microrates of herbicides to control grass and broadleaf weeds. Farmers initially applied the microrates at the sugarbeets’ two-leaf stage, then applied it periodically for several weeks.

There were a lot of trips across the field with the sprayer during those years, Baldwin said.

"We were spraying microrates every four to six days for six weeks,” he said. “I grew up in a band sprayer. I went from a 24-foot band sprayer to a 48-foot band sprayer over the years.”

Covering the ground with the 48-foot sprayer was a big improvement over the narrower versions.

“I thought it was a Cadillac sprayer.” Baldwin said.

Applying microrates was pretty effective for reducing weed pressure in the sugarbeets, Khan said.

“That did a fairly good job of weed control if growers could go in the field in a timely manner,” he said. Meanwhile, growers also cultivated the fields.

“If the weather cooperated, you had a fairly clean field,” Khan said. However, May and June, the months that the herbicides were applied, were typically rainy months, which made it difficult to get into the field to spray the weeds.

Baldwin Farms constantly kept an eye on the weather to see if rain was predicted so they could get a jump on spraying before it fell and made the fields too muddy to get into them, Baldwin said.

There also was a chance of injury to the young plants every time they were sprayed.

Besides band spraying, the Baldwins cultivated sugarbeet fields, which increased the amount of labor needed to raise the crop.

“Now the cultivator has become obsolete,” Baldwin said.

John E. Franz, an organic chemist, discovered glyphosate in 1970 while working for Monsanto. Roundup, a broad spectrum, non-selective herbicide, was approved for use in 1974 to control weeds in a variety of crops, including wheat, soybeans and corn. In 1996, Roundup Ready soybeans, a genetically modified crop that was resistant to glyphosate, were introduced. Other genetically modified crops, including corn, canola and alfalfa, followed.

Trevor Peterson / Agweek file photo

Thomas Peters, sugarbeet agronomist and weed control specialist for North Dakota State University and University of Minnesota, in 1995 worked on the early Roundup Ready sugarbeet project at Monsanto.

Part of his job working in product development was to determine the rate of Roundup needed to control the weeds in Roundup Ready sugarbeets.

“All we needed was a very small set of experiments to demonstrate that the sugarbeet safety was extremely great,” Peters said. “It was probably one of the easiest development projects I’ve been associated with.”

Field scale production research on Roundup Ready sugarbeets, funded by the Beet Sugar Development Foundation, was conducted in Idaho in 2006. The next year, groups of farmers in Michigan, Minnesota, North Dakota and Wyoming planted Roundup Ready sugarbeets.

Roundup Ready sugarbeets were approved for commercial use in U.S. sugarbeets in 2008.

The commercial production of Roundup Ready sugarbeets was successful and had the highest adoption rate in the United States of any genetically modified crop, Khan said.

Baldwin recalls that the first time spraying Roundup Ready beets required trust in the technology, but its success quickly proved that the trust was warranted.

“Once you saw this and saw it worked, you were a true believer,” he said. “I think we were 100% Roundup after the first year.”

Plant injuries were reduced after the Baldwins started planting Roundup Ready sugarbeets because fewer passes were needed.

Meanwhile, Roundup Ready sugarbeets had comparable yields to conventional varieties, then increased over time because there was less competition from weeds, Khan said.

Mikkel Pates / Agweek file photo

However, herbicide resistance developed in fields where one mode of action was consistently used.

“Anytime you use any pesticide over and over, you have selection pressure,” Khan said.

Weeds in Roundup Ready sugarbeets planted in fields that were rotated with conventional crops such as wheat and Liberty Link soybeans didn’t develop resistance. Sugarbeet experts are encouraging farmers to widen their rotations and use different modes of action to control weeds.

“Overall, it has been a blessing for our producers, especially those at the northern end of the (Red River) Valley who plant wheat before sugarbeets,” Khan said.

Baldwin Farms, which plants sugarbeets, edible beans, soybeans and wheat in a four-year rotation on their farm about 35 miles from the U.S.-Canada border, has not had a problem with Roundup resistance, as they use different modes of action on other crops.

“We’re rotating to help avoid resistance,” Baldwin said.

“Roundup is still an effective herbicide,” Peters said. “It doesn’t control everything like it used to, but it's still a very effective weed control in sugarbeets.”

Peters expressed amazement that, given the intensive research that went into developing Roundup Ready crops, weeds have developed resistance to them.

“The amount of resources and the amount of effort that it took to develop a crop that could tolerate Roundup, I never believed that resistance would be possible,” he said. ”I marvel at what weeds have been able to accomplish.”

Researchers are now working on second generation herbicide tolerant sugarbeets that are Liberty, Roundup and dicamba tolerant, Peters said. Rotating crops, using different modes of action to control weeds, and identifying — and eliminating — escapes before they reproduce will be important to reducing the chances of herbicide resistant weeds.

“We need to make sure we learn from our experiences the first time as we develop our second generation,” Peters said.

The second generation of herbicide-tolerant sugarbeets will be available sometime in the next several years, he said.