The agricultural giants are seeking Health Canada and Canadian Food Inspection Agency safety assessments for the introduction of four varieties of corn and soybeans bio-engineered to tolerate 2,4-D choline and another proven broadleaf weed killer, dicamba.
Dow AgroSciences, a subsidiary of Dow Chemical, hopes to have 2,4-D-tolerant “Enlist” field corn on the North American market next year. Rival Monsanto plans a limited launch of dicamba-tolerant soybeans in 2014, while Dow wants to unveil 2,4-D soybeans in 2015.
Health Canada would not discuss the companies’ specific safety submissions for the proposed novel foods, saying such information is “confidential” while under government review.
Regulatory sanctions also are sought by the “Big Farma” duo in the United States, where a fierce battle to sway public opinion and regulatory approval is underway.
Field corn already has limited, natural tolerance to 2,4-D and dicamba. But critics believe Enlist’s genetically-modified resistance to the chemicals will lead to widespread spraying, overspraying and potential contamination of unprotected neighbouring crops.
That, in turn, could lead to resistance to 2,4-D and dicamba and another step along what some in agriculture say is a worrisome “herbicide treadmill.”
The concern is not unfounded. Both of the proposed new seedlings are the industry’s response to increasing numbers of “superweeds” impervious to glyphosate, the most popular broad-spectrum weed herbicide for decades. The situation mirrors the human overuse of antibiotics that has triggered drug resistance to bacteria, viruses and other bugs.
2,4-D is another matter.
Enlist’s shrillest critics dub it “Agent Orange corn,” a misconstrued reference to 2,4-D’s history with the infamous defoliant Dow and Monsanto helped manufacture for U.S. military use in Vietnam. (A manufacturing flaw in another ingredient of Agent Orange, 2,4,5-T, was blamed for the cancers and other serious health problems among U.S. servicemen and Vietnamese.)
Dow and its supporters point out 2,4-D, once the most widely used herbicide in the world, is also the most studied chemical on the planet. Regulators in Canada, the U.S. and the European Union have all declared it to be safe if used as directed.
Four separate federal scientific assessments will be required before the products can hit the Canadian market, for human food safety, animal feed safety, plant biosafety and pesticide safety. The process, much of it based on reviews of raw company data, typically takes 18 to 24 months.
“It’s a very thorough auditing,” says Luc Bourbonnière, section head of the novel food section at Heath Canada, responsible for the food safety assessment.
Nutrition, toxicology, allergenicity and chemistry are all considered by his section. “What we’re making sure is that this GM corn is no different than the (conventional) one.”
With those approvals in hand, Enlist will move, “farmers forward at a critical juncture in agriculture,” says Kenda Resler Friend, a Dow AgroSciences spokeswoman.
“We can banter around the world population numbers all we want, but the reality is there’s no more land and limited water. We’ve got to be part of a solution here, so we’re excited that we’re doing that, having technology in hand today that can be a very important part of the solution.”
Still, the optics of the new 2,4-D corn and soybeans are difficult for some to swallow.
Ontario just marked the third anniversary of its pioneering provincial heath-protection law banning cosmetic pesticide use, including 2,4-D and dicamba, on lawns, gardens, school yards and parks.
Yet if the federal government approves the companies’ bids, Ontarians and Canadians in provinces with similar laws will be encouraged to douse two food crops with 2,4-D and dicamba but not their dandelions.
The debate, like others in biotechnology, is a potent blend of emotions, science and business.
Dow, Monsanto and their allies, including major U.S. farm organizations, say urgent action is needed to fight an invasion of glyphosate-resistant farm weeds.
The herbicide is best known under the Monsanto brand name Roundup, for spraying on Roundup Ready corn, soybean and cotton genetically modified to tolerate glyphosate. The weeds die while the plants survive.
But the enormous success of the “Roundup revolution” that began in the 1990s has led to widespread dependence and overuse of glyphosate, resulting in superweeds immune to its killing properties.
Weed resistance is not new. The first such plant in the world was wild carrot along Highway 401 near Milton, Ont., in the 1950s that grew resistant to heavy 2,4-D spraying by road maintenance crews.
The difference today is the scope of the problem. Glyphosate use dominates North American agriculture and increasingly, so too, do glyphosate-resistant weeds.
The resilience of nature is evident across almost five million hectares of superweed-infested U.S. farmland. Some runaway weeds in the southern U.S. are said to be big enough to stop combines dead in their tracks.
“This is our No. 1 issue,” Arkansas crop consultant Chuck Farr told a national “summit” of weed experts in Washington Thursday. “It is a challenge every day, every field.
Typically, the “super” in superweeds describes their immunity to the previously all-powerful glyphosate, not the weeds’ physical size.
In southwestern Ontario, two glyphosate-resistant broadleaf weed species — Giant Ragweed and Canada Fleabane — were found in nine fields between 2008 and 2010, the first such glyphosate resistance documented in Canada.
By last fall, 125 fields were infested.
A third glyphosate-resistant weed, Kochia, recently was confirmed in southern Alberta.
In Canada, “it’s important that we don’t overstate the problem, however … we can’t turn back the clock, we already have those weeds, the important thing is that growers implement strategies so that we don’t (see a) third and fourth glyphosate-resistant weed in Ontario,” says the University of Guelph’s Peter Sikkema, a leading expert on agricultural weed management.
Without efficient weed control, farmers face increased production costs, reduced crop yields and the prospect of returning to the laborious practice of tilling their fields, which they say promotes soil erosion, pesticide run-off into streams and rivers and increased fuel use.
A 2010 study by the U.S. National Academy of Sciences concluded the environmental effects of GM crops are less adverse, or at least equivalent to those of non-GM crops. GM crop pesticide regimes, for example, actually have reduced pesticide use compared with conventional crops, the research found.
Now Dow, Monsanto and other companies are taking weed management technology a step further with the creation of “stacked” GM crops that can withstand spraying with not one, but two or three herbicides.
Enlist seeds are engineered with recombinant DNA to tolerate Dow’s “Enlist Duo,” herbicide, containing a reformulation of the 1940s-era 2,4-D, as well as glyphosate, to target weeds that have not yet developed immunity.
Dow says the herbicide has been specially formulated to reduce 2,4-D’s known characteristics to drift and to vaporize into a gas, both of which can harm neighbouring crops. Company officials, however, concede there is little beyond moral suasion to prevent farmers from using older, more volatile brands of 2,4-D.
Meanwhile, Monsanto, in partnership with BASF, has developed soybean and cotton that can tolerate the existing herbicide dicamba.
As with 2,4-D, it mimics natural plant hormones, called auxins, which control broadleaf plant growth. When sprayed with the herbicides, the weeds grow uncontrollably, disrupting normal functions and inducing death.
Enlist’s opponents, led by the Save Our Crops Coalition of U.S. fruit and vegetable growers and canners, estimate 2,4-D use will mushroom with Enlist. The resulting chemical drift and volatility will kill and injure sensitive crops, from tomatoes to grapes, kilometres away and poison the habitats necessary for their pollinators, they argue.
Though Enlist is a genetically-modified field corn — not sweet corn — critics contend Enlist Duo’s 2,4-D will find its way into the food chain and food supply.
The chief uses for field corn are as livestock feed and for ethanol fuel. An estimated 25 per cent of the food products on a typical grocery store’s shelves contain field corn-derived ingredients, in everything from breads to toothpaste, according to Agriculture Canada.
Original Article
Source: ottawa citizen
Author: Ian Macleod
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