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The term “pesticides” includes herbicides, insecticides and fungicides.

The industry promised that genetically modified (GM) crops would reduce the use of pesticides in farming. Instead, herbicide use has increased with the use of GM crops. CBAN’s latest research has found that herbicide sales in Canada increased by 130% since genetically engineered herbicide-tolerant crops were introduced (1994-2011). For details see our report “Are GM crops better for the environment?”

After 20 years, 86% of the GM crops grown in Canada are herbicide-tolerant, and the rest are insect-resistant (some are both).

The United Nations Food and Agriculture Organization reports that 21.9 million kilograms of herbicides were sold in Canada in 1994. Numbers from Health Canada’s annual reports show that by 2011, this number had increased by 130% to 50.3 million kilograms.

The widespread cultivation of glyphosate-tolerant crops, in particular, has driven up the use of glyphosate-based herbicides. Glyphosate is the top pesticide ingredient sold in Canada, followed by 2,4-D and glufosinate ammonium. Glyphosate use in Canada tripled between 2005 and 2011, climbing from 30.2 million litres to 89.7 million in Western Canada, and from 3.8 million litres to 12.3 million in Eastern Canada.

This increased use of glyphosate has resulted in the emergence and spread of glyphosate-resistant weeds. In response, biotechnology companies have genetically engineered crops to be tolerant to the older herbicides 2,4-D and dicamba. These GM crops will further increase the herbicide load in the environment and lead to even more herbicide-resistant weeds.

GM insect-resistant (Bt) crops have reduced insecticide use in some countries. The Canadian government has not monitored the impact of Bt crops on insecticide use in Canada. However, insects are beginning to develop resistance to Bt crops in the US and other countries, and farmers are turning to other insecticide applications to control them. Additionally, Bt plants themselves produce insecticidal toxins that are released into the environment.

Herbicide-tolerant crops reduce weed diversity in and around fields, which in turn reduces habitat and food for other important species, including the Monarch butterfly. Studies have also observed that Bt crops can have negative impacts on non-target insects, including pollinators, and soil and water organisms.

For details please see “Are GM Crops Better for the Environment?” CBAN’s second report in the GMO Inquiry 2015



April 2017: The Canadian Food Inspection Agency (CFIA) has published the results of its testing of foods for glyphosate residues (2015-2016) The CFIA tested a total of 3,188 food samples for the herbicide glyphosate. Glyphosate was found in 29.7% of samples. Glyphosate residues above MRLs were found in 1.3% of samples. (The majority of GM crops are genetically modified to be glyphosate-tolerant.)

April 2017: CBAN has submitted comments to the Pesticide Management Regulatory Agency on the Cumulative Risk Assessment Framework, to raise the need to assess the impacts of herbicide-tolerant crops on herbicide use/exposure. Click here to read the comments from CBAN.

October 2016: A new review (monograph) on glyphosate from Pesticide Action Network Interantional

August 2015: A new article in the New England Journal of Medicine argues that assessment of genetically modified food safety should also be tied to assessing the human health risks of the herbicides applied to GM crops. “We believe that the time has therefore come to thoroughly reconsider all aspects of the safety of plant biotechnology…The National Toxicology Program should urgently assess the toxicology of pure glyphosate, formulated glyphosate, and mixtures of glyphosate and other herbicides.”

The International Agency for Cancer Research (IARC) of the World Health Organization (WHO) has concluded that:

  • Glyphosate, the world’s most-used chemical ingredient for weed control, is a “probable human carcinogen” (March 2015)
  • 2,4-D, the second most-used herbicide in Canada, is a “possible human carcinogen” (June 2015)


Pesticides and GM Crops

Click here for more information on 2,4-D tolerant crops

“Are GM Crops Better for the Environment?” May 2015, CBAN’s second report in the GMO Inquiry documents the rise in herbicide sales with genetically modified crops in Canada and examines the environmental impacts.

“What next after a ban on glyphosate—more toxic chemicals and GM crops? Or the transformation of global food systems?” The African Centre for Biodiversity (ACB), the Network for a GE Free Latin America (RALLT) and the Third World Network. June 2015. A number of countries have already taken action to reduce or halt the use of glyphosate in response to the IARC assessment. While glyphosate is still in use and is heavily relied upon for GM soy production in particular, Monsanto and other biotechnology and agro-chemical companies are already planning for business after glyphosate. A plethora of GM crops that are tolerant to multiple toxic herbicides – including 2,4-D and dicamba – are already approved for the market, while Monsanto has recently sought the potential acquisition of Syngenta, the world’s largest producer of herbicides.

Pesticides and Pollinators

Hidden Costs of Toxic Seed Coatings: Insecticide Use on the Rise, Factsheet, Center for Food Safety, US, June 2015. Scientists have identified pesticides—specifically a group of insecticides called neonicotinoids (abbreviated as “neonics”)—as likely to be an important cause of declining pollinator populations and poor pollinator health. Neonics are the most widely used insecticides in the world, and have been repeatedly shown to have lethal and sub-lethal effects on beneficial insects.

Pesticide Toxicity

Glyphosate and Cancer Risks: Frequently Asked Questions, Center for Food Safety, US, May 2015

The world’s most used weed-killer is probably carcinogenic – so what? Meg Sears, Prevent Cancer Now, June 2015

Pesticides and Our Health, Greenpeace International, May 2015

Synthetic pesticides have been widely used in industrial agriculture throughout the world since the 1950s. Over time, many of these chemicals have become extremely pervasive in our environment as a result of their widespread repeated use and, in some cases, their environmental persistence. Some take an extremely long time to degrade, such that even those banned decades ago, including DDT and its secondary products, are routinely found in the environment today.

As a consequence of this persistence, and potential hazards to wildlife, effect-related research on the impact of pesticides has increased exponentially over the past 30 years (Köhler and Triebskorn 2013). It is now clear that these effects are wide and varied. Over the same period, scientific understanding of the effects of pesticides on human health and their mechanisms of action has also expanded rapidly, with studies revealing statistical associations between pesticide exposure and enhanced risks of developmental impairments, neurological and immune disorders and some cancers.

Nevertheless, proving definitively that exposure to a particular pesticide causes a disease or other condition in humans presents a considerable challenge. There are no groups in the human population that are completely unexposed to pesticides, and most diseases are multi-causal giving considerable complexity to public health assessments (Meyer-Baron et al. 2015). Furthermore, most people are exposed to complex and ever changing mixtures of chemicals, not just pesticides, in their daily lives, through multiple routes of exposure. Pesticides contribute further to this toxic burden.

More Resources

Synthetic pesticides are not permitted for use in organic food production. Here is more information on the organic standard in Canada.

Organizations with up-to-date information on pesticide toxicity and related issues: