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Costs of Resistance: Bad Feelings and 2,4-D

(16 June - Cropchoice News) -- An investigative report published yesterday in a Canadian newspaper provides new details on the appearance of triple resistant volunteer canola on the Canadian prairies. Reports on the resistant canola first emerged early this spring. The appearance of such weeds, in so short a time since the commercialization of biotech canola, has raised questions about the economics of herbicide resistant crops, outcrossing and herbicide use.

Canola is a major crop in western Canada, where farmers grow a large amount of herbicide resistant acreage. Americans farmers planted just over 1 million acres of canola last year.

The Toronto Globe and Mail report details the story of Tony Heuther, a Sexsmith, Alberta canola and wheat producer who, in 1998, ran into volunteer canola he couldn't kill. In 1997, Heuther had been experimenting with different varieties of canola, looking for the right fit for his farm. In fields separated by a road and, in another case, 500 yards apart, Heuther put in three varieties of herbicide-resistant canola. He planted Quest, a Roundup-resistant variety from the Alberta Wheat Pool, Innovator, a Liberty-resistant variety from Aventis (AgrEvo), and 45A71, a Pursuit and Odyessy-tolerant variety bred by Pioneer Hi-Bred.

In 1998 Heuther wanted to switch to wheat in the fields where he had planted Innovator, the Libertylink variety, and 45A71, the Pioneer oilseed. Before planting Heuther applied Roundup to the fields to kill off weeds. It killed everything but clumps of volunteer canola. He tried again with Roundup. The canola still didn't die. Heuther says "I knew I had a real problem. I just couldn't figure out how to get rid of the stuff."

Specialists confirmed that the hardy volunteers were Roundup resistant. It was thickest by the side of the road across from the field where Quest had been planted. Further tests on Heuther's canola released earlier this year confirmed that some seed was triple-resistant: Roundup, Liberty, nor Pursuit could kill it.

But 2,4-D will. And that's what Canadian farmers have been advised to buy and spray on resistant volunteers, adding a potential kink to the "cost-effective", "simplicity" and "environmentally-friendly" selling points industry uses to promote herbicide resistant crops. Says highly-regarded canola expert Keith Downey, "The fact is that plants tolerant to Liberty and Pursuit are also present in many fields. However, growers don't recognize such plants because Liberty and Pursuit are not used for chemfallow or spraying around waste places. If Roundup is to be used for chemfallow or killing vegetation around various farm sites, to avoid volunteers tolerant to the new broad-spectrum herbicides, apply a phenoxy herbicide such as 2,4-D together with the Roundup."

Monsanto blames farmer management practices. Monsanto Canada's biotechnology chief says "If farmers practice good agronomics, outcrossing of GMO canola won't be an issue. There are 20,000 farmers in Canada using Roundup Ready canola, and we've only had a few cases of unexpected canola volunteers." Heuther does not agree, countering, "I've had my fill of being controlled by large companies. Monsanto led us to believe that this kind of thing wouldn't happen. There were no warnings until they were made aware of what happened on my farm."

SOURCE: Globe and Mail, Canola Digest (via farmsource.com), E.A. Clark, University of Guelph