Red River beet results show promise, also pitfalls

FARGO, N.D. -- A new survey shows Roundup Ready beets were a success in the Red River Valley in its maiden year of 2008.

But while the glyphosate-resistant beets have proven themselves as the best tool sugar beet growers have against weeds, there are potential problems on the horizon, says Jeff Stachler, North Dakota State University and the University of Minnesota's new extension sugar beet weed specialist. Here since May, Stachler came from Ohio and is a nationally known expert on glyphosate resistance in weeds.

"There is no better herbicide than we have ever used in our entire lives to control weeds than glyphosate," Stachler says. "And it doesn't look like we'll ever see another product like it."

He warns that the success with weed control in Roundup Ready sugar beets may be short-lived unless producers apply the glyphosate-active ingredient properly -- all of the time.

Weeds that are injured but survive to produce even a few seeds can create future concerns, he says. Resistant weeds showed up in the first year of Roundup Ready beets.

"We now have resistance to the best herbicide ever discovered -- exclamation point," says Stachler, who spoke Dec. 3 at Northern Ag Expo seminar in Fargo, N.D. The two-day trade show brought moderate crowds to the Fargodome as farmers chewed away at the last of the corn crop, but seminars like Stachler's drew intense interest.

Stachler says that unless the crop protectant industry comes up with a new form of chemistry, farmers may have to turn to "other strategies, outside of chemicals, to control weeds." He half-jokes that perhaps John Deere will develop a "robot that goes through the field" after chemicals are used and "kill the weeds that are left." That may be only alternative, in the absence of "new sites of action" in herbicide activity.

Largely positive

Sugar company and Extension Service survey data after year one are in and are largely positive, especially for producers who have a history of dense weed populations, Stachler says.

Some growers this year waited longer than normal to start applying glyphosate, and then adverse weather extended this further. This probably cut yields and, in some instances, some of those plants set seed. Necessary subsequent applications controlled most weeds.

"Because sugar beets are so susceptible to herbicides that carry over, there are very strict guidelines on what type of herbicide and crop rotations we want to be practicing," Stachler says.

But Roundup Ready sugar beets are at greater risk for selecting glyphosate-resistant weeds if the beets follow other Roundup Ready crops where only glyphosate is used.

Stachler says producers always need to add ammonium sulfate to improve control for any weed, but for lamb's-quarters, they should add a nonionic surfactant.

"I think we need to put surfactants in with any glyphosate formulations as long as it's not prohibited from being put in there," Stachler says. "We need to use the higher rate range because we have these individuals that are escaping."

The level of resistance is low for glyphosate, especially in lamb's-quarters and kochia. Because of that, it will take longer for resistance to develop, but once it does, it will be a big problem.

One of the realities is the proliferation of Roundup Ready crops in the region. They immediately become "weeds" for sugar beet producers growing Roundup Ready beets.

Farmers incur costs in controlling these volunteers, especially if they can't tank mix a secondary herbicide or must make an extra pass to apply it.

There were about 529,000 acres beets grown in the Red River Valley area in 2008. About 421,000 of those were for American Crystal Sugar in Moorhead, Minn., and 108,000 for Minn-Dak Farmers Cooperative of Wahpeton, N.D.

Of the total, about 53 percent of Crystal's acres were Roundup Ready beets and Minn-Dak had about 50 percent.

Poorer yields, so far

At Crystal, conventional varieties yielded an average of 25.9 tons per acre and the Roundup Ready varieties yielded 25.2 tons, according to preliminary figures.

"This (difference) should be a short-term thing because the Roundup Ready varieties are not as agronomically sound as conventional varieties at this point," Stachler says. "Over time, that difference will disappear, and it'll probably disappear anyway because we won't have conventional beets."

Among other things, the Roundup Ready beets also may have been affected by weed competition a lack of disease resistance.

Sugar content for conventional beets was 17.55 percent, while Roundup Ready beets were 17.64 percent. Sugar lost to molasses was a little greater for Roundup Ready beets than conventionals.

Total income per acre was estimated at $1,150 for conventionals and $1,121 for Roundup Ready beets. So the growers can expect to receive an estimated $28.50 more per acre for conventional beets vs. Roundup Ready beets. Meanwhile, herbicide costs should be about $20 less per acre for conventional vs. Roundup Ready costs, according to company estimates.

For this reason, Roundup Ready beets produced $48.50 per acre poorer results than conventionals, based on both costs and revenues, Stachler says.

"That's not true for everyone, of course," he says.

People with bigger weed problems should have had better results.

A related annual NDSU survey of beet growers has been conducted for the past 26 years. Stachler offered preliminary results of the survey, taken from 239 growers that represent 111,609 acres.

Among the top production problems in 2008, identified by the survey responses, weeds were No. 1 at 30 percent. That category was down from 46 percent from last year, probably because of the advent of Roundup Ready beets, Stachler says.

About 24 percent said their biggest production problem was a combination of the diseases rhizoctonia and aphanomyces. Another 21 percent said it was stand and emergence.

"I think part of this has to do with Roundup Ready sugar beets because 12 percent reported no major problems -- things went fine, which is a great increase from the 4 percent a year ago," Stachler says.

Based on the survey, about 52 percent of growers of Roundup Ready beets used the rate suggested by Stachler's predecessor, Alan Dexter.

"We skipped over the 0.75-pound-per acre rate -- what some people call the 'normal use' rate -- and jumped right up to 1 pound," Stachler says. "That's good to see that percentage."

The average total pounds of glyphosate applied for the whole growing season for beets was more than 2 pounds per acre, which is almost more than what can be used on corn or soybeans for a growing season.

Farmers with Roundup Ready fields went over their fields an average of 2.2 times for weed control. Average trips across the field for conventional growers was 4.7 trips, which included most weed control practices -- a difference of more than two trips.

$48.50 convenience factor

Stachler says he knew there would be a convenience factor for timing of chemical applications.

"I just didn't realize individual growers were willing to pay for that with a $48.50 difference in profits," Stachler says.

Only 1.2 percent of the Roundup Ready beet acres were treated with glyphosate that had been tank-mixed with Stinger to catch Roundup Ready soybeans and wild buckwheat.

Growers rated weed control was "excellent" in 80 percent of the cases or more for each of the glyphosate rates in the survey. Growers who used the maximum rates, however, reported the best weed control.

The average number of row cultivations was 0.4 per grower for Roundup Ready beets. That compared with 1.3 for conventionals, which is down from 1.7 last year. Cultivations are thought to increase diseases, even though they are beneficial for weed control.

The worst weed problems in 2008 were pigweed at 27 percent, followed by kochia, lamb's-quarters and smartweed. Preliminary numbers from 100 Roundup Ready growers counted so far showed that seven individuals said pigweed still was a problem from various reasons.

"Because we've had Roundup Ready corn and soybeans, they're selecting for the resistance we're going to realize in the Roundup Ready sugar beets. This is a major concern."

A common theme Stachler saw in 2008 was that beet growers tried to control weeds with glyphosate after they'd become too large and too dense.

"We can't keep continuing to do this, folks," he says. He says allowing weeds to get too large will cut yields and allows glyphosate-resistant biotypes in the field. If there is dust in the air, the glyphosate ties to it and isn't as effective.

"Once you increase the level of resistance to the point where the 'recommended' use rate and dust is present at the time of application, then plants near the wheels are no longer getting a normal rate," he says.