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2,4-D- and Dicamba-Tolerant Crops

Glyphosate and glyphosate-tolerant crops are reaching the end of their life cycle due to the emergence of glyphosate-resistant weeds. With no new herbicides on the horizon, the seed and pesticide industry is encouraging farmers to use other herbicides and to adopt new GM crops that are tolerant to the older herbicides 2,4-D and dicamba (often these are stacked with tolerance to other herbicides, including glyphosate).

Canada was the first country in the world, in 2012, to approve 2,4-D-tolerant crops and a dicamba-tolerant soy. Health Canada and the Canadian Food Inspection Agency have approved genetically engineered 2,4-D-tolerant crops manufactured by Dow AgroSciences. Dow has genetically engineered “Enlist” corn and soy to tolerate its “Enlist Duo” herbicide that combines glyphosate and 2,4-D choline. The Enlist corn seeds will also be stacked with Monsanto’s Roundup Ready Corn 2 and SmartStax:Enviro report ad

  1. Corn DAS-40278-9 – with increased tolerance to 2,4-D
  2. Soybean DAS-68416-4 – tolerant to 2,4-D and glufosinate
  3. Soybeans DAS-44406-6 – tolerant to glufosinate, 2,4-D and glyphosate tolerance

A dicamba-tolerant soybean from Monsanto has also been approved.

There are already 16 species of 2,4-D resistant weeds around the world (five in the US and two in Canada) and six species resistant to dicamba, (two in the US and two in Canada). Charles Benbrook has predicted that widespread use of 2,4-D resistant crops in the US could increase herbicide use by another 50% (Benbrook, C., 2012. Impacts of genetically engineered crops on pesticide use in the U.S. – the first sixteen years. Environmental Sciences Europe, 24.)

CBAN and Équiterre, Nature Québec, the Canadian Association of Physicians for the Environment, Prevent Cancer Now, and Vigilance OGM denounced regulatory approval of Canada’s first corn and soy crop plants genetically engineered (also called genetically modified or GM) to tolerate doses of the herbicide 2,4-D because of concerns that the products will lead to increased herbicide use, with more toxic pesticides in the environment and our food.

Press Release – November 19, 2012: GM 2,4-D-Tolerant Crops set to Accelerate Pesticide Use: Groups denounce government approvals as reckless

Monsanto’s Dicamba-Tolerant Soy

The dicamba-tolerant soy from Monsanto is Roundup Ready 2 Xtend, because it will also be glyphosate tolerant. Roundup Ready 2 Xtend® soybeans contain genes that confer tolerance to glyphosate, an active ingredient in Roundup® brand agricultural herbicides, and dicamba, the active ingredient in XtendiMax™ herbicide with VaporGrip™ Technology.  Here is what Monsanto currently says about the status of the market status of this product (March 2017):

This product has been approved for cultivation in the U.S. and Canada, and for import in Australia/New Zealand, Colombia, China, Japan, Korea, Mexico, Taiwan, and Vietnam. The single events in this product have been approved for import in the EU. As of February 2, 2016, E.U. stack approval is in the final stage of approval and is expected but not guaranteed to be received in the near future. Any crop or material produced from this product can only be exported to, or used, processed or sold in countries where all necessary regulatory approvals have been granted. It is a violation of national and international law to move material containing biotech traits across boundaries into nations where import is not permitted. Growers should talk to their grain handler or product purchaser to confirm their buying position for this product. Growers should refer to for any updated information on import country approvals. (Accessed March 5 2017:


June 2017: Despite new labelling and application guidelines, drift from dicamba is continuing to cause widespread damage to crops in the US in 2017. Damage in Arkansas has been so extensive that the state’s Pesticide Committee has recommended an immediate ban on in-crop dicamba use in 2017. Read the story here.

August, 2016: Drift from dicamba is reportedly damaging crops in Canada and the US.

  • The US Environmental Protection Agency reported it has an “unusually high number of reports of crop damage that appear related to misuse of herbicides containing the active ingredient dicamba”. The EPA has not yet approved Monsanto’s new dicamba formula which is designed to reduce drift. Read the news story here.
  • In Canada: “We’re not just going to be spraying glyphosate on soybeans any more. We need two modes of action and we have to keep the drift from reaching other crops.” Read the news story here.

June 23, 2015: The World Health Organization’s International Agency for Research on Cancer (IARC) has classified the herbicide 2,4-D as a “2B – possible” carcinogen.