Roundup Ready Cotton

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Roundup Ready Cotton (RR Cotton) is genetically engineered cotton that has had its DNA altered to allow it to withstand the herbicide glyphosate (the active ingredient in Monsanto's herbicide Roundup). It is sometimes referred to as "glyphosate tolerant" cotton. When planting Roundup Ready cotton, a farmer can spray the entire crop with Roundup, killing only the weeds and leaving the cotton alive. However, one concern with the heavy use of Roundup on Roundup Ready crops is that it will lead to the development of Roundup resistant weeds (sometimes referred to as "superweeds").[1]

Impacts of RR Cotton

For more information, see the article on Roundup Ready Crops.

Impact on Herbicide Use

Predictably, the introduction of Roundup Ready cotton resulted in an increase of glyphosate (Roundup) use. This was not only because farmers could now spray their entire fields with glyphosate, but also because of "weed shifts," as weeds with some natural resistance to glyphosate became bigger problems following the adoption of RR cotton and the ubiquitous reliance on glyphosate that accompanied it. Then, after several years of widespread adoption of RR cotton, weeds began to evolve resistance to glyphosate. Specifically, between 1996 and 2008, the glyphosate rate of application per crop year has tripled on cotton farms.

"In cotton, the average rate of glyphosate rose from 0.63 pounds in 1996 to 1.89 pounds in 2007 — clearly good news for the manufacturers of glyphosate herbicides, but bad news for farmers and the environment. Most of this increase was driven by the need to make additional Roundup applications. One application of glyphosate brought about adequate control in 1996 on most cotton farms. Just two years later, 1.5 applications were necessary. By 2003, an average of two applications were made, and by 2007, 2.4 applications. During this time period, the average one-time rate of application went up by 25%, from 0.63 to 0.79 pounds per cotton acre. Glyphosate use on cotton per crop year rose 18.2% per year from 1996 to 2007 as a result of the introduction of RR cotton."[2]
"During the first five years of use, HT upland cotton reduced the total volume of herbicides used per acre, an outcome brought about by the high degree of efficacy of glyphosate in the early years of HT crops. By crop year 2001, each acre of HT cotton required more herbicide than the average conventional cotton acre. The margin of difference rose incrementally over the next decade, reaching 0.65 pounds per acre in 2008."[2]

Evolution of Glyphosate Resistant Weeds

Impact on Yields



  • February 14, 1995: Monsanto petitions the U.S. to deregulate MON 1445 and MON 1698.
  • July 11, 1995: U.S. deregulates Monsanto's MON 1445 and MON 1698.
  • December 19, 1996: Canada deregulates Monsanto's MON 1445.
  • 1997: Monsanto introduces MON 1445, branding it "Roundup Ready® Cotton."



  • 2010: Monsanto rebrands its products "Genuity™ Roundup Ready® Cotton" (MON 1445) and "Genuity™ Roundup Ready® Flex Cotton" (MON 88913)

Brands and Manufacturers


Bayer CropScience:

Adoption Rates in the U.S.

Following the introduction of Roundup Ready cotton, its adoption by U.S. farmers grew. The USDA offers data on the percent of cotton in the U.S. that are herbicide tolerant between 2000 and 2012:[7]

  • 2000: 46%
  • 2001: 56%
  • 2002: 58%
  • 2003: 59%
  • 2004: 60%
  • 2005: 61%
  • 2006: 65%
  • 2007: 70%
  • 2008: 68%
  • 2009: 71%
  • 2010: 78%
  • 2011: 73%
  • 2012: 80%

Articles and resources

Related SourceWatch articles


  1. William Neuman and Andrew Pollack, "Farmers Cope With Roundup-Resistant Weeds," New York Times, May 3, 2010, Accessed February 18, 2011.
  2. 2.0 2.1 Charles Benbrook, "Impacts of Genetically Engineered Crops on Pesticide Use: The First Thirteen Years" and Supplemental Tables, The Organic Center, 2009.
  3. Novel Food Decisions - Approved Products, Health Canada, Accessed August 15, 2012.
  4. Bayer to launch new GlyTol cotton varieties in 2009," Delta Farm Press, October 20, 2008.
  5. Product Safety Summaries, Accessed August 15, 2012.
  6. Product Safety Summaries, Accessed August 15, 2012.
  7. Genetically engineered varieties of corn, upland cotton, and soybeans, by State and for the Unites States, 2000-12, USDA ERS.

External resources

External articles