GMO Crops and
In his book “
,” 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
companies were eagerly pursuing this application of genetic engineering because with
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 cre
ate “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.”
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).
Scientists note that weeds resistant to glyphosate (the active ingredient in Rou
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.
A 2001 paper by an Iowa State University scientists note
s 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.
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.
An Iowa State scientist warns that reliance on GMO crops
with glyphosate will likely lead to
resistant weeds. He n
otes that "
Monsanto has taken a strong position stating that the likelihood of
eloping 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
horeseweed (mare's tail) surviving spraying with Roundup starting in 2000.
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."
Glyphosate resistant horseweed (aka
marestail or Conyza canadensis
) weeds are confirmed throughout
and soon after in NJ and Maryland.
Farmers and scientists find
"volunteer" canola (rapeseed) weeds that resist t
hree different herbicide
modes, created when by cross
contamination from GMO crops. It is described as
"the first documented
of gene stacking in canola occurring without deliberate human intervention."
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.
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
What we’ve embarked
[with GMO crops]
is a ve
ry 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.”
A news report notes a warning from Canadian scientists, whose research shows GMO crops can spread
superweeds and damag
GMO and organic fields. Monsanto denies the findings, stating that
because glyphosphate does not linger in soil, weeds are unlikely to evolve resistance.
Seeing a business opportunity created by superweeds from their GMO crops, Monsanto files a pat
application for tank
mixing of any herbicides for use on resistant weeds in RR crop fields.
The biotech and pesticide company Syngneta
releases “guidelines” to deal with resistant weeds
recommending farmers use more Syngenta herbicides with their GMO glyphosate
including paraquat, a chemical that is banned or severely restricted in a dozen countries and classified
by EPA as a possible carcinogen.
nfirmation of glyphosate
resistant marestail weeds in Delaware and Tennessee, an Iowa
State scientists confirm they found "variabl
e response" to glyphosate in waterhemp
fields, including no control in some fields.
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.
A farm journal reports that talks on g
dominated a recent weed science meeting,
ates on resistant weeds in Delaware, Maryland,
Tennessee, Kentucky, southern Indiana and
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] pr
A Monsanto ad sent to farmers denies the problem of weed resistance and suggests that growers do
resistance management programs.
Stating that "
d weeds don't produce
seeds," the ad encourag
es farmers to use r
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
year. The ad
earns a place in an Iowa State scientis
ts' "Herbicide Ad Hall of Shame
for promoting the very
rategies that lead to weed resistance.
A Virginia study finds common lambsquarters weeds survive high doses of glyhosate, and finds that the
tolerance trait passes to the next weed generation.
resistant waterhemp reported in Missouri
and resistant lambsquarters is suspected in
several Midwestern states.
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 glyphosa
te and continued adoption of
Palmer amaranth weeds resistant to glyphosate are confirmed in Georgia cotton fields. Monsanto
recommends growers add additional herbicides with their GMO crops
, including older, dangerous
ls that the company earlier claimed would be replaced with the advent of GMO crops.
DuPont announces the release of its new “Optimum” GMO crops, engineered for glyphosate
weed problems. The new crops are tolerant of both glyphosate and
DuPont’s ALS (
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….”
A Georgia weed expert notes that glyphosate re
Palmer amaranth (pigweed)
weeds have been
reported in 50 fields throughout the state, noting that “
it's going to be a major devastating impact
farmers. Many farmers begin to turn to expensive additional weed killers and tilling to control
The first documented case of resistant hairy fleabane in the US is confirmed in California.
reports widespread glyph
resistant fields are devastating
farmers in Argentina. First
observed there in 2004,
the resistant Johnson grass (
double farmers herbicide costs. Argentina is 2nd to the U.S. in GMO crop acreage.
Glyphosate resistant ragweed is observed in
, 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.
journal reports that crops resistant to glyphosate and the herbicide dicamba
weeds, will be available in a few years. Monsanto and herbicide maker BASF announce a collaboration
to bring the new crop to market.
Dicamba is a reproductive toxin and potential groundwater
contaminant listed as a “bad actor” chemical
for its environmental and health effects.
Dow announces it is seeking regulatory approval for new GMO crops tolerant to the company’s 2,4
, a component of Agent Orange that is a dangerous neurotoxin and endocrine
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
Powles states that
resistance evolution is a major adverse development because glyphosate is a one in
year discovery that is as important for reliable global food production as penicillin is for
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.
Ten years after the first confirmed glyphosate resistant weeds from GMO crops, the
New York Times
notices the problem, quoting
one farm expert
that weed resistance is “[T]
he single largest
threat to production agriculture that we have ever seen
A Penn State weed scientist notes that glyphosate resistant weeds now infest more than 11 million acres
of U.S. farmland
fold increase over the past three years.
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
ith 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
Jack Doyle, 1985,
, Viking Penguin, New York, 1985, pp. 214
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, "
Modified Crops and the Environment
Agron. J. 92:797
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
Tolerant Crops: A Revisitation."
Weed Technology. 2003. Volume 17:202
Miguel Altieri, “The Environmental Risks of Transgenic Crops: An Agroecological Assessme
nt.” Beyond Pesticides,
Spring/summer 1998, online at
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
Juliana Barbassa, "
Attack of the 12
." Associated Press, August 10, 2005, online at
Mark VanGessel, "Determining the Presence of Glyphosate
Resistant HorseWeed Under Field Conditions."
University of Delaware Coop Extension, March 13, 2001, update online at
A new breed of superweed.
and mail, June 15, 2000, online at
Tom Spears, "
Superweeds' invade farm fields
." Ottawa Citizen, February 6, 2001, online at
Adrian Ewins, "
Canola popping up where it’s not wanted
." Western Farm Press, July 12, 2001, online at
Jonathan Leake, "
GM fields spread new superweeds
." Sunday Times (UK),
August 12, 2001
, online at
David Dechant, "
Monsanto Sees Opportunity in Glyphosate Resistant Volunteer Weeds
." CropChoice News,
August 3, 2001, online at
Syngenta Announces Guidelines To Prevent Weed Resistance To Glyphosate Herbicides
.” Syngenta press
release, February 2
Mike Holmberg, "Weed resistance is the Achilles' heel of effective herbicides." Successful Farming, April 2002,
available on request.
Cited in "
Monsanto Sales Down, CEO Out and Weed Resistance Up
." Ohio State University, December 20,2002,
Mike Holmberg, "
Glyphosate resistance dominates weed science meeting
." Successful Farming, December 6,
2002, online at
Bob Hartzler, "Are Roundup Ready Weeds in Your Future II?" Iowa State University, January 2003, online at
King, S.R., et al. 2004. Differential response of common lambsquart
ers (Chenopodium album) biotype to
glyphosate. Weed Sci. Soc. Am Abstr. 44:68.
See Facts About Glyphosate
Resistant Weeds online at
See “Biology and Management of Common Lambsquarters,”
Nandula, V.K., et al (2005). “
weeds: current status and future outlook
on Pest Management August 2005: 183
187. Online at
“Investigation Confirms Case Of Glyphosate
Resistant Palmer Pigweed In Georgia.” Monsanto press release,
September 13, 2005, online at
Dupont names glyphosate, ALS Tolerant Trait Optimum(TM) GAT(TM)
,” DuPont press release, March 3, 2006.
Georgia cotton growers fight pigweed
,” Associated Press, July 8, 2006, online at
Another weed in south Central Valley shows resistance to herbicide
." UC Davis, August 23,
2007, online at
Shane Romig, "
Roundup resistant weeds spreading in Argentina
." Dow Jones Newswire, September 26, 2007,
U of G Researchers Find Suspected Glyphosate
,” University of Guelph press release, May 7,
2009, online at
Stephanie Dearing, “Glyphosate
resistant giant ragweed has spread in southern Ontario,” Digital Journal,
November 23, 2010, online at
Ann Toner, “Dicamba
resistant soybeans coming.” Nebraska Farmer, Feb 2009, online at
Dow AgroSciences submits new family of herbicide tolerance traits
.” September 2, 2009
, online at
See Natural Resources Defense Council, “Petition to Revoke All Tolerances and Cancel All Registrations for the
D,” Nov 6, 2008, online at
January 19, 2010
, online at
William Neuman and Andrew Pollack, “
Farmers Cope With Roundup
.” NY Times, May 3, 2010,
Penn State Live, “
resistant weed problem must be dealt with, expert says
2010, online at
David Mortenson, et al (2012). “
Navigating a Critical Juncture for Sustainable Weed Management
Vol. 62, No. 1 (January 2012), pp. 75