Tag Archives: Dicamba

U.S. Court Overturns Dicamba Herbicide Registration

CBAN – June 2020

June 2020: A U.S. court overturned the registration of the herbicide dicamba, because of the “enormous and unprecedented” damage to neighbouring crops from pesticide drift. The court ruling means that three dicamba formulations – sold by Monsanto (Bayer), BASF, and Corteva (Dow-Dupont) – are now illegal, and their associated genetically engineered (genetically modified or GM) dicamba-tolerant seeds are irrelevant. However, the U.S. Environmental Protection Agency (EPA) –  the regulator responsible for allowing registration – has responded by allowing U.S. farmers to use up their existing stocks of dicamba. In 2017, Monsanto (now Bayer) introduced a new dicamba formulation to be sold along with the company’s new GM dicamba-tolerant seeds. About two-thirds of the soybeans and three-quarters of the cotton planted by U.S. farmers is now dicamba-tolerant.

Herbicide Sales Increased 243% (1994-2017)

Health Canada information shows an increase in herbicide sales of 243% from 1994-2017. The first genetically engineered herbicide-tolerant crops were introduced in 1995.

Call to Re-think Genetically Engineered Herbicide-Tolerant Crops

August 2019: The Canadian Biotechnology Action Network (CBAN) and Prevent Cancer Now (PCN) are calling for a review of the use of genetically engineered (genetically modified or GM) herbicide-tolerant crops in Canada, in response to Monsanto’s request for government approval of GM corn MON 87429 that can withstand applications of four herbicides, including 2,4-D and dicamba.

Glyphosate gives way to dicamba and 2,4-D

As glyphosate-resistant weeds spread across North America and the herbicide glyphosate consequently loses its usefulness as a weedkiller, Monsanto (now Bayer) is replacing its GM glyphosate-tolerant soy with GM dicamba-tolerant soy. In the US, the new dicamba-tolerant varieties are increasing the use of the herbicide dicamba. Bayer says its new dicamba formula is less prone to herbicide drift but, across the US, neighbouring crops that are not dicamba-tolerant are being damaged. This is leading many farmers to buy GM dicamba-tolerant seeds as a strategy to protect their crops. Bayer estimates that U.S. farmers will plant about 50 million acres of dicamba-tolerant soybeans in 2019, 60% of all the soybeans planted in the country. Corteva (DowDuPont) says it will widely launch its 2,4-D-tolerant soy in Canada in 2020, with some sales in 2019. Click here for some background on 2,4-D- and dicamba-tolerant crops

Glyphosate is a “probable human carcinogen”

In 2015, the International Agency for Cancer Research (IARC) of the World Health Organization (WHO) 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)


Glyphosate and Dicamba Herbicides Increase Antibiotic Resistance in Bacteria

Oct 13 2018 –  by Sustainable Pulse

A new study has found that some of the world’s most widely used herbicides, Roundup (glyphosate) and Kamba (dicamba), increase the rate of antibiotic resistance development in bacteria by a factor of up to 100,000 times faster than occurs without the herbicide.

Both herbicides are used on GM crops engineered to tolerate them.

The new study adds to a growing body of evidence that herbicides used on a mass industrial scale, but not intended to be antibiotics, can have profound effects on bacteria, with potentially negative implications for medicine’s ability to treat infectious diseases caused by bacteria. University of Canterbury (New Zealand) Professor Jack Heinemann, one of the study’s authors, said, “The combination of chemicals to which bacteria are exposed in the modern environment should be addressed alongside antibiotic use if we are to preserve antibiotics in the long-term.”

An important finding of the new study was that even in cases where the herbicides increase the toxicity of antibiotics they also significantly increased the rate of antibiotic resistance, which the authors say could be contributing to the greater use of antibiotics in both agriculture and medicine.

Previously these researchers found that exposures to the herbicide products Roundup, Kamba and 2,4-D or the active ingredients alone most often increased resistance, but sometimes increased the susceptibility of potential human pathogens such as Salmonella enterica and Escherichia coli, depending on the antibiotic.

Prof Heinemann said, “We are inclined to think that when a drug or other chemical makes antibiotics more potent, that should be a good thing. But it also makes the antibiotic more effective at promoting resistance when the antibiotic is at lower concentrations, as we more often find in the environment. Such combinations can be like trying to put out the raging fire of antibiotic resistance with gasoline.”

The authors concluded that neither reducing the use of antibiotics nor the discovery of new ones may be sufficient strategies to avoid the post-antibiotic era. This is because bacteria may be exposed to other non-antibiotic chemicals that predispose them to evolve resistance to antibiotics more quickly. Herbicides are examples of some of the most common non-antibiotic chemicals in frequent global use. Thus antibiotic resistance may increase even if total antibiotic use is reduced, and new ones are invented, unless other environmental exposures are also controlled.

The new paper, “Agrichemicals and antibiotics in combination increase antibiotic resistance evolution” is published online in the peer-reviewed journal PeerJ on October 12 and can be downloaded without charge from here.