Agriculture contributes an estimated $8.8 billion annually to the Ohio economy. Soybeans and corn are the state’s two most planted crops, with 4.5 million acres of soybeans acres and 3.2 million acres of corn in 2011.
-National Agricultural Statistics Service, USDA
The arrival of Roundup Ready corn and soybeans in the 1990s simplified farmers’ herbicide problems in an affordable way and was such a success that up to 90 percent of corn, soybeans and cotton crops are now grown with Roundup Ready varieties.
With resistant weeds including marestail now flourishing in Ohio fields, many farmers are looking forward to the arrival of corn, soybeans and cotton crops that are genetically modified to tolerate the herbicide 2,4-D, which kills weeds in a different way.
Dow AgroSciences hopes to get government approval for use by next year for corn, 2015 for soybeans and cotton “after that.”
But even those who look at 2,4-D crops as “a good tool” worry that the herbicide’s ability to damage neighboring crops is a problem. And still others worry that the 2,4-D crops usher in a new era in the man vs. weed battle — one in which all farmers need to do what many have resisted to this point: abandon the short-term stewardship of their bottom lines for more varied herbicide programs in the name of longer run benefits.
Agriculture is big business, too, contributing an estimated $8.8 billion to the state’s economy.
Matt Harbur, resource agronomist for Trupointe, the area cooperative formerly called Landmark, knows personally what a game-changer Roundup Ready crops were. Although he earned his doctorate at Iowa State University in weed science, the success of Roundup dried up money for research and he moved into organics instead.
“It’s been so attractive because it’s been so inexpensive,” he said. And even cheaper, generic brands (of Roundup) have “extremely high effectiveness.”
With the coming of 2,4-D crops, “the key thing will be more public concern with drift,” Harbur said.
Although 2,4-D has been around since the 1940s and farmers have experience with it, it is a volatile chemical. That means not only is 2,4-D is more likely to drift on the air to neighboring crops than Roundup, it’s likely to do much more damage when it arrives.
“It can wipe out a neighboring crop if it’s not used wisely,” said Ian Heap, who travels the world from Corvallis, Ore., with the International Survey of Herbicide Resistant Weeds.
Because of that, Michael D.K. Owen, who taught Harbur at Iowa State and has been there for 30 years called the use of 2,4-D “a whole different ballgame.”
Owen said that not only is the herbicide more potent, its use in a crop system will call for the chemical to be sprayed at different times of year. Two, four-D is often used now as a pre-emergent herbicide when temperatures are cooler and fewer crops are out. As part of a crop system, it will be sprayed more often in June and July when volatility increases with temperature, and other crops that could be damaged have come up.
In some late spring and summer conditions, said Owen, “the only way to eliminate the risk (of harming a neighboring crop) is not to apply the herbicide.”
Mark Loux, professor in the Department of Horticulture Science at Ohio State University, is not as worried.
He said he’s satisfied that new formulations made by Dow are “way, way less volatile” than earlier versions.
Changes promised by Dow AgroSciences were significant enough that the Save Our Crops Coalition, a group of vegetable growers and canners, last month dropped its opposition to Dow’s proposal for approval from 2,4-D engineered corn.
Not everyone, of course, is satisfied.
In a letter to the Secretary of Agriculture, 147 farm, food, health, public interest, consumer, fisheries and environmental organizations, including the Sierra Club, asked the Department to deny Dow’s petition.
Estimating that approval would increase the amount of 2,4-D sprayed in the country annually from the current 27 million pounds to more than 100 million pounds, the letter describes the increased use of chemical pesticides as an “arms race” with weeds that’s destined to fail.
“Weed resistance to 2,4-D will not be prevented or even slowed by the approaches that failed so spectacularly with Roundup Ready crops: voluntary ‘stewardship plans and grower education.’”
The letter argues that “if these new … crops systems are to be introduced at all, mandatory weed resistance management programs with strict limitations on frequency of use over time are absolutely necessary.”
Even many who favor approval of 2,4-D ready crops agree that the results of “voluntary stewardship plans and grower education” must improve.
In what he described as “a race against evolution,” Harbur said “there are no new chemical ways to kill a weed … in the pipeline.”
The lack of new “mode of action” herbicides is likely a reason the new wave of genetically modified crops pairs the new technology of genetic modification with the existing herbicide, 2,4-D.
Heap added that a major contributor to the lack of expansion of herbicides likely was the success of Roundup, which “has taken the money out of the market.”
“There was little point for other companies to develop other herbicide modes of action,” he said.
In the face of constantly adapting weeds, agri-science must get the most it can out of the current herbicides by using them in different combinations and more judiciously.
This will demand that farmers move to better herbicide management practices, which means not relying on a single herbicide like Roundup, but mixing in Roundup and other herbicides, like 2,4-D.
Those who have done so already by combining spring spraying of 2,4-D with post emergent treatments of Roundup are not, by and large, having problems with resistant weeds.
Loux does not like one of the solutions proposed by Dow: combining Roundup and 2,4-D in a single solution. Although it would produce a less volatile mix of chemicals and kill a broad spectrum of weeds immediately, he said, it might also put weeds already resistant to Roundup on the fast track to becoming resistant to 2,4-D as well, leaving farmers soon facing a weed that’s resistant to both.
Dow AgroSciences joins the extension and university agriculture experts in promoting better practices, saying that 2,4-D tolerant crops might “significantly reduce (the) rate of herbicide increase in concert with a sustainable, integrated weed management plan.”
But that remains the big if.
Environmental critics are not alone in questioning whether farmers, whose eyes are always on the bottom line, will develop more varied herbicide treatment plans in a situation that seems to require it.
Even Loux, who says competition for scarce rental land will encourage best practices, admits that in years of trying to persuade farmers to vary their herbicide programs, he’s found the going slow.
“There’s guys that get it, and everybody else is just developing,” he said.
In a time when the pressure on limited herbicides is likely to increase, the best he can muster is to say, “I think we’ll manage OK.”
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