GMO Crops and Superweeds: Chronology
1982
In his book “Altered Harvest,” researcher Jack Doyle uncovers the chemical industry’s strategy with GMO
“herbicide tolerant” crops. The industry trade journal Chemical Week reported in July 1982 that pesticide companies were eagerly pursuing this application of genetic engineering because with herbicide-tolerant GMO crops “The theory is that farmers would then be willing to use even more of the weed killers….” A biotech consultant states that these GMO crops create “a complementary demand for both the chemical and the seed,” and another notes that pesticide companies want the GMO varieties to insure continued demand for their weed killers, noting that “They’re trying to cover themselves.” In
November, the biotech company Calgene announces it has developed a gene for resistance to glyphosate, the active ingredient in Monsanto’s Roundup herbicide (Monsanto will later buy Calgene).
i
1995
Scientists note that weeds resistant to glyphosate (the active ingredient in Roundup, Monsanto's herbicide for use on the company's Roundup Ready crops) in Australia suggests that other weeds can become resistant, especially with reliance on one herbicide with GMO crops.
ii
1998
A 2001 paper by an Iowa State University scientists notes that farmers there identified poor control of weeds with glyphosate on RR crops as early as 1998, and found resistant waterhemp and/or horseweed even after a very short history of glyphosate use.
iii
A University of California agroecologist warns that “the increased use of the herbicide [glyphosate] will result in weed resistance” with the advent of GMO “Roundup Ready” crops.
iv
November 1998
An Iowa State scientist warns that reliance on GMO crops used with glyphosate will likely lead to resistant weeds. He notes that "Monsanto has taken a strong position stating that the likelihood of resistance developing to Roundup is very low," but he predicts that "It is likely that most growers will have problems with weeds able to tolerate the normal use rate of Roundup before Roundup resistant weeds appear." v
2000
A California farmer found horeseweed (mare's tail) surviving spraying with Roundup starting in 2000.
The Associated Press stated that by 2003 "...he had tripled the concentration of the herbicide, and had doubled the applications, but the weeds were growing thicker than ever." vi
March 2000
Glyphosate resistant horseweed (aka marestail or Conyza canadensis) weeds are confirmed throughout
Delaware and soon after in NJ and Maryland.
vii

June 2000
Farmers and scientists find "volunteer" canola (rapeseed) weeds that resist three different herbicide modes, created when by cross-contamination from GMO crops. It is described as "the first documented case of gene stacking in canola occurring without deliberate human intervention." viii
February 2001
A panel of Canadian scientists say that GMO canola is "beginning to develop into a major [weed] problem," as the GMO crop invades other crop fields across the country. A University microbiologist calls the GMO weed "a classic example" of a superweed.
ix
July 2001
Farmers in Canada report the widespread problem of GMO canola appearing as a weed in their fields, even in fields where the crop was never grown. One University scientist states, "What we’ve embarked on here [with GMO crops] is a very big experiment. We’re releasing these traits into the environment and we’re assuming we’re going to be able to contain them and we can’t.” x
August 2001
A news report notes a warning from Canadian scientists, whose research shows GMO crops can spread superweeds and damage non-GMO and organic fields. Monsanto denies the findings, stating that because glyphosphate does not linger in soil, weeds are unlikely to evolve resistance.
xi
Seeing a business opportunity created by superweeds from their GMO crops, Monsanto files a patent application for tank-mixing of any herbicides for use on resistant weeds in RR crop fields.
xii
February 2002
The biotech and pesticide company Syngneta releases “guidelines” to deal with resistant weeds xiii , recommending farmers use more Syngenta herbicides with their GMO glyphosate-resistant crops, including paraquat, a chemical that is banned or severely restricted in a dozen countries and classified by EPA as a possible carcinogen.
April 2002
Following confirmation of glyphosate-resistant marestail weeds in Delaware and Tennessee, an Iowa
State scientists confirm they found "variable response" to glyphosate in waterhemp weeds in Iowa fields, including no control in some fields.
xiv
December 2002
Monsanto competitor Syngenta releases a paper stating that farmers may lose up to 17% of their land value due to glyphosate resistant weeds from GMO crops.
xv
A farm journal reports that talks on glyphosate resistance dominated a recent weed science meeting, with updates on resistant weeds in Delaware, Maryland, Tennessee, Kentucky, southern Indiana and southern Ohio.
xvi

January 2003
An Iowa State scientist's update on glyphosate resistant weeds notes that "With the manner that glyphosate is being used in the Midwest, resistance is inevitable. When resistance develops, we will need to control these biotypes with existing herbicides - no new modes of action are coming down the pipeline in the foreseeable future....there can be significant costs associated with [this] problem." xvii
May 2003
A Monsanto ad sent to farmers denies the problem of weed resistance and suggests that growers do not need to consider weed resistance management programs. Stating that "Dead weeds don't produce seeds," the ad encourages farmers to use repeated doses of Roundup on their fields and suggests there are no weed problems even for farmers who use RR crops in the same fields year-after-year. The ad earns a place in an Iowa State scientists' "Herbicide Ad Hall of Shame" xviii for promoting the very strategies that lead to weed resistance.
2004
A Virginia study finds common lambsquarters weeds survive high doses of glyhosate, and finds that the tolerance trait passes to the next weed generation.
xix
2005
Glyphosate-resistant waterhemp reported in Missouri xx and resistant lambsquarters is suspected in several Midwestern states.
xxi
August 2005
A review of glyphosate-resistant weeds by USDA scientists notes that “The problem of weed species evolving resistance is expected to increase with intense use of glyphosate and continued adoption of
[GMO] crops.” xxii
September 2005
Palmer amaranth weeds resistant to glyphosate are confirmed in Georgia cotton fields. Monsanto recommends growers add additional herbicides with their GMO crops xxiii , including older, dangerous chemicals that the company earlier claimed would be replaced with the advent of GMO crops.
March 2006
DuPont announces the release of its new “Optimum” GMO crops, engineered for glyphosate-resistant weed problems. The new crops are tolerant of both glyphosate and DuPont’s ALS (sulfonylurea) herbicides. In addition to allowing farmers to spray the extra herbicides, DuPont brags that the new seeds allow farmers to spray “higher glyphosate application rates….” xxiv
July 2006
A Georgia weed expert notes that glyphosate resistant Palmer amaranth (pigweed) weeds have been reported in 50 fields throughout the state, noting that “it's going to be a major devastating impact” for

some farmers. Many farmers begin to turn to expensive additional weed killers and tilling to control the weeds.
xxv
August 2007
The first documented case of resistant hairy fleabane in the US is confirmed in California.
xxvi
September 2007
Dow Jones reports widespread glyphosate-resistant fields are devastating farmers in Argentina. First observed there in 2004, experts say the resistant Johnson grass (sorghum halepense) weeds could double farmers herbicide costs. Argentina is 2nd to the U.S. in GMO crop acreage.
xxvii
2008
Glyphosate resistant ragweed is observed in Ontario xxviii , and later in 2009 is confirmed as the first such resistant weed found in Canada. By 2010, resistant weeds are found in 16 of 57 fields tested.
xxix
February 2009
A farm journal reports that crops resistant to glyphosate and the herbicide dicamba, to address resistant weeds, will be available in a few years. Monsanto and herbicide maker BASF announce a collaboration to bring the new crop to market.
xxx Dicamba is a reproductive toxin and potential groundwater contaminant listed as a “bad actor” chemical for its environmental and health effects.
xxxi
September 2009
Dow announces it is seeking regulatory approval for new GMO crops tolerant to the company’s 2,4-D herbicide xxxii , a component of Agent Orange that is a dangerous neurotoxin and endocrine-disrupting chemical.
xxxiii
January 2010
A leading weed scientist warns that glyphosate resistance brought on by overuse of GMO crops threatens world food security. Writing in the Proceedings of the National Academy of Sciences, Stephen
Powles states that
Glyphosate resistance evolution is a major adverse development because glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease.... It is not an exaggeration to state that the potential loss of glyphosate to significant areas of world cropping is a threat to global food production.
xxxiv
May 2010
Ten years after the first confirmed glyphosate resistant weeds from GMO crops, the New York Times notices the problem, quoting one farm expert who states that weed resistance is “[T]he single largest threat to production agriculture that we have ever seen.” xxxv

September 2010
A Penn State weed scientist notes that glyphosate resistant weeds now infest more than 11 million acres of U.S. farmland – a fivefold increase over the past three years.
xxxvi
January 2012
A paper in BioScience, the journal of the American Institute of Biological Sciences notes that GMO crops have resulted in widespread glyphosate resistant weeds and warns that developing new GMO crops with additional modes of herbicide resistance will exacerbate the problem by creating multiple resistant weeds and forcing farmers to spray even more harmful chemicals on our food and in the environment.
xxxvii i Jack Doyle, 1985, Altered Harvest, Viking Penguin, New York, 1985, pp. 214-217. ii Matthews, J.M., and S.B. Powles. 1995. "Glyphosate or glufosinate resistant transgenic crop and pasture species:
Can target weeds develop resistance to these non-selective herbicides?" Cited in Barton and Dracup, "Genetically
Modified Crops and the Environment," Agron. J. 92:797–803 (2000). Online at https://www.soils.org/publications/aj/abstracts/92/4/797 iii Pringnitz, B. A. 2001. Issues in Weed Management for 2002. Extension Publication PM 1898, Iowa State
University, University Extension Service. Cited by Martinez-Ghersa, et al, " Concerns a Weed Scientist Might Have
About Herbicide-Tolerant Crops: A Revisitation." Weed Technology. 2003. Volume 17:202–210. iv Miguel Altieri, “The Environmental Risks of Transgenic Crops: An Agroecological Assessment.” Beyond Pesticides,
Spring/summer 1998, online at http://www.beyondpesticides.org/infoservices/pesticidesandyou/Spring%20and%20Summer%2098/The%20Envir onmental%20Risks%20of%20Transgenic%20Crops.pdf
v Bob Hartzler, "Are Roundup Ready Weeds in Your Future?" Iowa State University, paper presented to the 1998
Crop and Pest Management Short Course, St. Paul, MN. Online at http://www.weeds.iastate.edu/mgmt/qtr98-
4/roundupfuture.htm
vi Juliana Barbassa, "Attack of the 12-foot horseweed." Associated Press, August 10, 2005, online at http://www.gmwatch.org/latest-listing/1-news-items/2989-herbicide-resistant-strains-plague-farmers vii Mark VanGessel, "Determining the Presence of Glyphosate-Resistant HorseWeed Under Field Conditions."
University of Delaware Coop Extension, March 13, 2001, update online at http://ag.udel.edu/extension/IPM/ResourceGuide/WF13-Determining%20the%20Presence%20of%20Glyphosate-
Resistant%20Horseweed.pdf
viii Gillian Steward, "A new breed of superweed." Toronto Globe and mail, June 15, 2000, online at http://www.organicconsumers.org/ge/superweed.cfm
ix Tom Spears, "Superweeds' invade farm fields." Ottawa Citizen, February 6, 2001, online at http://www.organicconsumers.org/gefood/canolasuperweeds.cfm
x Adrian Ewins, " Canola popping up where it’s not wanted." Western Farm Press, July 12, 2001, online at http://www.producer.com/2001/07/canola-popping-up-where-its-not-wanted/ xi Jonathan Leake, "GM fields spread new superweeds." Sunday Times (UK), August 12, 2001, online at http://ipm.osu.edu/trans/08_121.htm
xii David Dechant, "Monsanto Sees Opportunity in Glyphosate Resistant Volunteer Weeds." CropChoice News,
August 3, 2001, online at http://www.cropchoice.com/leadstry05f6.html?recid=390.%20http://cli.gs/JmLY1S xiii “Syngenta Announces Guidelines To Prevent Weed Resistance To Glyphosate Herbicides.” Syngenta press release, February 25, 2002. xiv Mike Holmberg, "Weed resistance is the Achilles' heel of effective herbicides." Successful Farming, April 2002, available on request. xv Cited in "Monsanto Sales Down, CEO Out and Weed Resistance Up." Ohio State University, December 20,2002, online at http://ipm.osu.edu/trans/122_201.htm
xvi Mike Holmberg, " Glyphosate resistance dominates weed science meeting." Successful Farming, December 6,
2002, online at http://www.biotech-info.net/dominating.html

xvii Bob Hartzler, "Are Roundup Ready Weeds in Your Future II?" Iowa State University, January 2003, online at http://www.weeds.iastate.edu/mgmt/2003/glyresistance.shtml
xviii See http://www.weeds.iastate.edu/mgmt/2003/monad.shtml
xix King, S.R., et al. 2004. Differential response of common lambsquarters (Chenopodium album) biotype to glyphosate. Weed Sci. Soc. Am Abstr. 44:68. xx See Facts About Glyphosate-Resistant Weeds online at http://www.extension.purdue.edu/extmedia/gwc/gwc-
1.pdf
xxi See “Biology and Management of Common Lambsquarters,” online at http://www.extension.purdue.edu/extmedia/BP/GWC-11.pdf
xxii Nandula, V.K., et al (2005). “Glyphosate-resistant weeds: current status and future outlook.” Outlooks on Pest Management August 2005: 183-187. Online at http://www.ars.usda.gov/SP2UserFiles/Place/64022000/Publications/Reddy/Nandula-GRW12.pdf
xxiii “Investigation Confirms Case Of Glyphosate-Resistant Palmer Pigweed In Georgia.” Monsanto press release,
September 13, 2005, online at http://monsanto.mediaroom.com/index.php?s=43&item=415 xxiv “Dupont names glyphosate, ALS Tolerant Trait Optimum(TM) GAT(TM),” DuPont press release, March 3, 2006. xxv “Georgia cotton growers fight pigweed,” Associated Press, July 8, 2006, online at http://www.accessnorthga.com/detail.php?n=121060 xxvi Stephanie Klunk, "Another weed in south Central Valley shows resistance to herbicide." UC Davis, August 23,
2007, online at http://www.ipm.ucdavis.edu/NEWS/hairy_fleabane-news.html
xxvii Shane Romig, "Roundup resistant weeds spreading in Argentina." Dow Jones Newswire, September 26, 2007, online at http://www.lasojamata.net/en/node/77 xxviii “U of G Researchers Find Suspected Glyphosate-Resistant Weed,” University of Guelph press release, May 7,
2009, online at http://www.uoguelph.ca/news/2009/05/u_of_g_research_19.html
xxix Stephanie Dearing, “Glyphosate-resistant giant ragweed has spread in southern Ontario,” Digital Journal,
November 23, 2010, online at http://digitaljournal.com/article/300579 xxx Ann Toner, “Dicamba-resistant soybeans coming.” Nebraska Farmer, Feb 2009, online at http://magissues.farmprogress.com/NEF/NF02Feb09/nef035.pdf
xxxi See http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC32872 xxxii AgroNews, “Dow AgroSciences submits new family of herbicide tolerance traits.” September 2, 2009, online at http://news.agropages.com/News/NewsDetail---1550.htm
xxxiii See Natural Resources Defense Council, “Petition to Revoke All Tolerances and Cancel All Registrations for the
Pesticide 2,4-D,” Nov 6, 2008, online at http://www.beyondpesticides.org/documents/NRDC%2024-Dpetition.pdf
xxxiv PNAS, January 19, 2010, vol. 107, no. 3, 955-956, online at http://www.pnas.org/content/107/3/955.full
xxxv William Neuman and Andrew Pollack, “Farmers Cope With Roundup-Resistant Weeds.” NY Times, May 3, 2010, online at http://www.nytimes.com/2010/05/04/business/energy-environment/04weed.html?pagewanted=all xxxvi Penn State Live, “Growing Roundup-resistant weed problem must be dealt with, expert says.” September 14,
2010, online at http://live.psu.edu/story/48259 xxxvii David Mortenson, et al (2012). “Navigating a Critical Juncture for Sustainable Weed Management.” BioScience
Vol. 62, No. 1 (January 2012), pp. 75-84. Online at http://www.iatp.org/files/Mortensen%20et%20al%20%202012%20%20Navigating.pdf