Science in Society Archive

Let the World Learn from North American Farmers' Experience with GMOs

Prof. E. Ann Clark reviews the real scientific surveys that contradict every claim made by British academics regarding the benefits of GM crops in their government-funded ‘study’

I cannot fathom how British academics can still be quoted as saying that GM crops allow farmers to grow “high-quality food profitably”, in an “environmentally sensitive way”, and to attain “high yields while using less herbicide” [1] (see "UK Farmers Upbeat about GM Crops" Debunked, SiS 38). Roughly 99 percent of GM land on the planet is sown to just two traits - herbicide tolerance (HT) and Bt, which causes plants to synthesize their own insecticide. Nothing about quality.

Objective evidence of profitability is equally sparse, particularly if one factors in the lemon effect of lost markets due to the global rejection of GM. British growers might want to look for an article by Ian Mauro and Stef McLachlan at the University of Manitoba, Canada, due to appear in the journal Risk Analysis [2, 3] (Canadian Farmers’ Experience Exposes the Risks of GM Crops, SiS 38) This is the first ever publicly available survey in a peer reviewed journal of how Canadian farmers have been impacted by GM technology. It includes a quote by a Canadian farmer who said: “The loss of [European] markets due to GM had a huge financial impact. This was likely larger than the cost of controlling volunteers or benefit of easy weed control.”

This same 2003 survey of 370 farmers found that the greatest cited benefit among technology users (n=298) was operational, including timing and efficacy of weed control, facilitating farming of a larger landbase. Among 10 ranked benefits, increased yield was 6th and increased revenue ranked last. Among 10 cited risks, of greatest concern were loss of markets, loss of farmer rights under the Technology Use Agreement, higher seed costs, and lawsuits. Remember Percy Schmeiser (see Box)?

Schmeiser versus Monsanto

Percy and Louise Schmeiser are Saskatchewan canola growers and seedsavers. Monsanto accused them of patent infringement when the RR gene was found in some of the canola plants on their land. All allegations of theft or ‘brownbagging’ were withdrawn at the outset due to lack of evidence [4, 5] (Schmeiser's Battle for the Seed, SiS 19). The case went to the Supreme Court of Canada, which reached a split decision [6], and the Schmeisers did not have to pay Monsanto anything. In 2007, the Schmeisers received the Right Livelihood Award, generally regarded as the alternative Nobel Prize for their “courage in defending biodiversity and farmers’ rights” [7].

The Schmeisers are not alone. By 2005, Monsanto had filed 90 lawsuits against American farmers, and 147 farmers and 39 small businesses or farm companies have had to fight for their lives to avoid paying additional court costs, attorneys’ fees, and in some cases, costs incurred by Monsanto while investigating them [8] (Monsanto versus Farmers, SiS 26). The Center for Food Safety estimated that Monsanto has been awarded over $15 million by judgments granted in their favour.

So how about yield? Pay attention, British growers, to a recent USDA retrospective on GM in the US, which stated [9]: “Currently available GE [genetically-engineered] crops do not increase the yield potential of a hybrid variety. In fact, yield may even decrease if the varieties used to carry the herbicide-tolerant or insect-resistant genes are not the highest yielding cultivars.”

Likewise, researchers with Agriculture and Agri-Food Canada (AAFC) summarized the Canadian experience with GM crops [10]. They cited a 2-year AAFC trial over 5 western Canadian locations where HT outyielded conventional canola weed control practices in just 6 of 30 comparisons, all at sites and years of particularly problematic weeds. They also cited evidence from public variety trials in Ontario, where much of the Canadian corn and soybean are grown, showing not an increase, but a 4 percent yield decrease in GM soybeans and no yield benefit from GM corn. So, let’s stop with the “higher yield” mantra and stick with the scientifically defensible evidence. Somebody might as well learn from our experience.

Less herbicide? Environmentally sensitive? As of 2008, a total of 63 weed biotypes in 13 species are now tolerant to glyphosate, the active ingredient in Monsanto's Roundup Ready herbicide [11]. Of these, 41 were detected in soy or cotton fields starting in 2000. Of the 41, 32 were reported from the US, with the rest predominantly from Brazil and Argentina, paralleling global use patterns of HT technology. The evolution of weed resistance in GM crop fields has increased, not decreased, both the rate and frequency of application of herbicides, and obliged tank-mixing with other herbicides to cope with intractable weeds. According to Charles Benbrook [12], we now use more, not less, herbicide.

So if GM crops don’t actually do what was promised, apart from simplifying the process of weed control, then why are so many North American farmers growing them? The AFFC researchers reported [8] that planting choices for western Canadian canola producers had simplified down to one non-herbicide tolerant (HT) cultivar and 48 private sector HT cultivars (HT crops have been generated through both mutagenic and transgenic methods. Mutagenized HT crops include those tolerant to imidazolinone (IMI), while transgenic HT crops include those tolerant to glyphosate (e.g. RR), glufosinate ammonium (e.g. LL), and bromoxynil (BX)). Was this because they were all so pleased with what HT is doing for them, or was it just safer than becoming the next Percy Schmeiser? Next time British farmers or policymakers hear that 95 percent of western Canadian canola plantings are HT, they might want to ask themselves if this is a fate they want for themselves.

E. Ann Clark is an Associate Professor in the Department of Plant Agriculture at the University of Guelph, Ontario, Canada

Article first published 11/04/08


  1. Ho MW. “UK farmers upbeat about GM crops” debunked. Science in Society 38 (to appear).
  2. Mauro, I. and McLachlan, S. (2008) Farmer knowledge and risk analysis: post release evaluation of herbicide tolerant canola in Western Canada. Risk Analysis 28 (in press).
  3. Ho MW. Canadian farmers’ experience exposes the risks of GM Crops. Science in Society 38 (to appear).
  4. Clark EA. The federal crime of Percy Schmeiser. Genetics Society of Canada Bulletin, June 2001,
  5. Ho MW. Schmeiser’s battle for the seed. Science in Society 19, 13-14, 2003.
  6. Clark EA. So, who really won the Schmeiser Decision?, 10 June 2004,
  7. 2007 Right Livelihood Awards highlight solutions to global challenges. Monsanto vs Schmeiser.
  8. Burcher S. Monsanto versus farmers. Science in Society 26, 33+48, 2005.
  9. Fernandez-Cornejo, J. and M. Caswell. 2006, The First Decade of Genetically Engineered Crops in the United States. USDA-ERS
  10. Beckie, H. J.; Harker, K. N.; Hall L. M.; Warwick, S. I.; Legere, A.; Sikkema, P. H.; Clayton, G. W.; Thomas, A. G.; Leeson, J. Y.; Seguin-Swartz, G.; Simard, M.-J. (2006) A decade of herbicide-resistant crops in Canada. Can. J. Plant Sci. 86:1243-1264
  11. International Survey of Herbicide Tolerant Weeds,
  12. Benbrook, C. (2004) Genetically Engineered Crops and Pesticide Use in the United States: the first nine years.

Got something to say about this page? Comment

Comment on this article

Comments may be published. All comments are moderated. Name and email details are required.

Email address:
Your comments:
Anti spam question:
How many legs on a spider?