ISIS Report 18/01/10
GM Crops Increase Herbicide Use in the United States
The use of toxic herbicides on the rise due to the spread of
herbicide tolerant crops Brett Cherry
A fully referenced version of this paper
is posted on ISIS members’ website here, and
it can be downloaded here
Please circulate widely and repost, but you must give the URL of the original and preserve all the links back to articles on our website
The rapid rise in herbicide tolerant (HT)
crops is increasing the application of toxic herbicides to alarming levels in
the US, according to a comprehensive report  by the
Organic Food Center, USA. Research based on statistics from the US Department
of Agriculture (USDA) revealed that from 1996 to 2008 pesticide use increased
by 318 million pounds; a decrease of 64 million pounds in insecticide use 
was overwhelmed by an increase of 383 million pounds in herbicide use . Especially
worrying is that most of this increase (46 percent) took place between 2007 and
2008. This has led to major environmental concerns regarding the safety of
HT crops as they continue to dominate the corn, soybean and cotton markets in
the US. Ecological risks, such as herbicide resistant “super weeds,” and economic
impacts on farmers, were especially highlighted in the report released jointly with
the Union of Concerned Scientists and the Center for Food Safety, both also in
Announcing a new Report from ISIS. The most complete up-to-date summary of the dangers of GM agriculture in 52 pages. Buy Now, or download here
HT crops widespread
Data from the US National Agriculture
Statistics Service (NASS) indicate that between 1996 and 2008, farmers planted
941 million acres of HT corn, soybeans and cotton, with HT soybeans accounting
for 72 percent of total GM acres planted (see Tables 1a and 1b . GM soybeans
alone accounted for 92 percent of the increase in herbicide use. Despite a
decrease in the use of insecticides for Bt corn and cotton, the drastic rise in
the use of herbicides has led to an unprecedented increase in pesticide use
Table 1a Total acres of HT corn, soybeans
and cotton planted, 1996-2003 
Table 1b Total acres of HT Corn, soybeans
and cotton planted, 2004-2008 
In 2008, GM crops required over 26 percent more pounds of pesticides
per acre than conventional crops . If this trend continues, the report warns
that farmers will continue to be plagued by herbicide-resistant weeds and
higher costs for GM seeds, not to mention a greater risk to public health (see
later). GM corn seed prices could be three times the cost of conventional seeds
 and it has become more difficult for farmers in the US to buy non-GM seeds since GM corn has dominated the US market . In
2009, the cost of GE corn seed cost farmers between 19 and 34 percent of their
gross income and operating costs per acre . The false promises of GM companies
to increase yields and reduce costs with GM seeds have failed farmers in the US, resulting in economic exploitation and rising GM seed prices. Farmers who plant GM
soybeans will also pay extremely high prices for GM seeds, especially for
Monsanto’s new Roundup Ready 2 (RR 2) soybeans that cost $70 per bag,
reflecting a 143 percent increase in the price of GM seed since 2001 .
US farmers are not alone in witnessing the hazardous
impacts of GM seeds on their livelihoods. Farmers in India were promised
increased yields from Bt cotton seed, but they never came (see  Farmer
Suicides and Bt Cotton Nightmare Unfolding in India, SiS 45). Instead, they have suffered even worse from rising Bt cotton seed
prices that increased their indebtedness and mass suicides.
HT crops mean more herbicides
danger in cultivating HT crops is that they can tolerate large amounts of glyphosate
in addition to other herbicides, and increasingly more so over time (see Table 2).
In comparison, the amount of pesticides applied to non-GM crops has been decreasing,
and usually less per acre than GM crops, except for corn prior to 2006 (see
Table 3). Since then, the amount of pesticides applied to non-GM corn is less
than that applied to HT corn.
Table 2 Average pesticide use per acre for
corn, soybean and cotton, 2003-2008 and total pounds of pesticides applied,
Table 3 Average pesticide pounds (active
ingredient) applied per acre for conventional and HT varieties, 1996-2008 
herbicides mean superweeds and yet more herbicides
of more glyphosate herbicides has brought ecological disasters, especially in
herbicide resistant superweeds. As weeds become more resistant to glyphosate,
farmers apply more or spray multiple herbicides at once. The report comments
that “addressing the rapidly emerging problem of resistant
weeds in this way makes as much sense as pouring gasoline on a fire in the hope
of snuffing out the flames .” Due
to an increase in herbicide applications, new infestations of glyphosate
resistant plants such as pigweed (Palmer amaranth) and horseweed (marestail)
have become widespread . In order to kill glyphosate resistant weeds, other
toxic and deadly herbicides such as paraquat (N,N′-dimethyl-4,4′-bipyridinium
dichloride) and 2,4-D (2,4-Dichlorophenoxyacetic acid) are used. Paraquat
has been linked to Parkinson’s disease and is forbidden by the EU, while 2,4-D
is a well known component of the highly toxic defoliant Agent Orange used
during the Vietnam War. In light of their impacts on
public health, these pesticides should be banned altogether rather than be used
to compensate for weed resistance due to the over use of glyphosate.
planting of HT crops has made the US the “resistant weed epicentre of the
world” with 125 resistant biotypes of 68 weeds, infesting up to 18 million acres,
and probably much higher . According to the Weed Science Society of America
(WSSA), populations of glyphosate resistant weeds have risen 2.4 million acres
in 2007 to 5.4 million acres by early 2009, correlating with increased use of
glyphosate herbicides. Since 1996, the application of glyphosate per crop year
has tripled for cotton and doubled for soybeans, with an annual increase of
18.2 percent for cotton, 9.8 percent for soybeans and 4.3 percent for corn.
Private data on
pesticide use can be easily manipulated by biotech companies, making the need
for independent data collection imperative for understanding the environmental
impacts of GM crops and pesticide use. NASS began
making less frequent annual surveys of different field crops since 2002. Due to
cuts in funding by the Bush administration, NASS did not collect
pesticide use data for 2008 and data collection was limited to cotton and
apples in 2007. In order to make up for these shortcomings, the Organic Center had to base their results on estimates using the formula in Box 1 
Let H(HT) be the average amount of herbicide per acre
applied to HT varieties of a given crop and let H(non-HT) be the average amount
of herbicide applied to non-HT varieties of the same crop. If p is the number
of acres on which HT varieties of the crop are grown and q is the number of
acres on which non-HT varieties are grown, then the average herbicide used per
acre on the crop is
p × H(HT) + q × H(non-HT)
p + q
The average rate of herbicides for
conventional crops was subtracted from the average rate of herbicides applied
to GM crops to determine whether herbicide use rose or fell for a
particular year (see Table 3) . Other data in the report from the USDA Agricultural
Marketing Service (AMS) and the Economic Research Service (ERS) are used to calculate
the percentage of acres planted to HT crops . NASS
pesticide use data were not available for cotton in 2002, 2004 and 2006; for
corn in 2004 and 2006; and for soybeans in 2003 , and estimates had to be
made. Averages derived from statistical analyses are no substitute for empirical
data. In the US, not only universities and environmental groups depend on NASS
data, but also the farming industry and the EPA use the data to set pesticide
Critics of the Organic Center report who are also
consultants for biotech firms, such as PG Economics, UK, rely on surveys by Dmrkynetec (Doane Marketing Research), a US private research firm that supplies pesticide use data for the biotech industry.
2004 to 2007, the Dmrkynetec data show a greater increase in herbicide use for
conventional crops despite the adoption of low-dose herbicides by farmers
according to NASS data . The Dmrkynetec data also show an increase in
herbicide use for HT crops from 1998 to 2004 referred to in a report by PG Economics
. Yet PG Economics did not acknowledge the
increase, claiming it was not “a reasonable representation” of average
herbicide use for HT crops compared to conventional crops .
In criticising the
Organic Center Report, PG Economics accuses it of overstating herbicide use on
HT crops by 63.4 million pounds of active ingredient
. It then goes on to refer to its “peer reviewed analysis” that GM
crops have reduced herbicide consumption. PG Economics
does not refer to data from NASS, a US government agency, but uses only data
from Dmrkynetec, which PG Economics claims is the  “only comprehensive source of
pesticide use data.”
Not only is Dmrkyntec a marketing research firm, it also places
limits on how its data can be released publicly and does not reveal its data
collecting methods, making the data worthless for scientific
There are also other questionable sources of data on pesticide use
on HT crops that biotech companies cite in their public relations campaigns
through the National Center for Food and Agriculture Policy (NCFAP), USA.
The NCFAP, partly funded by the biotech industry, determines the
amount of pesticides used according to pest management systems recommended by
university scientists . The problem with this approach is that it does not
reflect the pest management systems that farmers actually use.
Thus, NCFAP reports that 3.23 pounds per acre of
herbicides was applied to conventional corn consisting of a mixture of 3.16
pounds of ‘pre-emergent’ and 0.07 ‘post-emergent’ mix of s-metolachlor/atrazine
. NASS, which sends enumerators out into the field to observe the amounts of
pesticides farmers actually spray , reports that conventional corn in 2005 had
a combined average rate of no more than 2.48 pounds per acre, not 3.23 . Using
NCFAP’s herbicide rates for conventional corn (3.23) and RR corn (2.5) gives a decrease
of 0.73 pounds per acre, instead of a slight increase of 0.02 pounds according
to NASS data . In the case of RR soybeans, NASS data reveal pesticide
applications to be 28 percent higher than the NCFAP estimates .
scientists and farmers are to understand the actual impacts of GM crops on
pesticide use they need access to data provided by NASS or other independent
sources. Private marketing research firms such as Dmrykynetec cannot serve the
public, especially with a price tag of $500 000 per year .
resistant weeds continue to spread rapidly, chemical companies are capitalising
on this opportunity by attempting to introduce other pesticides into the market
and toxic genes into GM crops. Already many crops have both HT and toxic Bacillus
thuringiensis (Bt) traits stacked together. Two Bt genes were used for
pests, such as the European corn borer and the corn root worm. These double
and triple-stacked versions made up 57 million acres of corn in 2008 compared
to around 14 million acres with single traits, most of which were HT . Bt was
found to be highly toxic to cattle who died after eating Bt maize (see  Cows Ate GM Maize & Died, SiS 21), and one of Monsanto’s patented Bt
corn seeds, MON810, is banned by many countries in the EU (see [10, 11] Acceptance of GM Crops
Exaggerated, SiS 42; Europe Holds the Key to a GM-Free
World, 5th Conference of GM-Free Regions, Food & Democracy, SiS
The marketing strategy of
chemical companies such as Monsanto and Dow AgroSciences to introduce multiple
toxic traits into GM crops is called “biotech trait penetration” . In GM
crop markets, farmers must pay a fee per trait, so instead of relying on single
trait varieties they must pay for multiple traits within the same crop. According
to the report, Monsanto and Dow AgroSciences will replace their triple stack GM
seeds with an eight GE (genetically engineered) trait product called “SmartStax”
by 2010, in their attempt to create a “captive consumer base”  where farmers
are backed into the corner of the GM market. SmartStax
corn, for example, will cost farmers more than twice as much as conventional
seeds . Farmers will be paying the high
‘technology’ costs for seeds plus proprietary herbicides to
corporation-conglomerates that will also control the price of the agricultural
commodities market, keeping it as low as possible.
herbicides and restore agriculture to the public
studies reveal that increased pesticide use and the planting of more GM crops
is a deadly combination. Public health risks due to GM crops’ tolerance to
glyphosate, for example, are worsened by the presence of adjuvants in
Monsanto’s Roundup herbicide formulations (see  Death By Multiple Poisoning,
Glyphosate and Roundup, SiS 42) and recent evidence has confirmed
that exposure to Roundup disrupts sex hormones (see 
Glyphosate Herbicides Now, SiS 43). Argentina has considered banning glyphosate
herbicides after researchers found it could cause birth defects (see  Glyphosate
Herbicide Could Cause Birth Defects, SiS
companies such as Monsanto are allowed to continue to monopolise agriculture,
conventional plant breeding programs will become obsolete. While endangering
public health and ecology, over dependence on toxic herbicides is also depriving
the world of one of its most precious resources, traditional, low-tech farming
practices. This can be restored by investing in organic agriculture that has
been shown to increase yields and produce more nutritious food (see  UK Food Standards
Agency Study Proves Organic Food Is Better,
SiS 44) without the use of any pesticides.
Furthermore, in patenting GM
seeds and forcing them onto farmers, biotech companies are attempting to
control our food supply. The future of agriculture lies with organic, non-GM
methods that can feed the world in the developing and developed world (see  Food Futures Now: *Organic
*Sustainable *Fossil Fuel Free).
There are 6 comments on this article so far. Add your comment
|R. K. S. Rathore Comment left 6th March 2010 08:08:11|
Use of Glyphosate to remove weeds is a very handy tool, if it harms the fertility of soil we have to think in terms of sustainable Agriculture? Promotors of Glyphosate use should come out with specific information. The world is facing shortage of food grains. Use of Glyphosate effectively controls weed and help in more productivity per unit area with lesser amount of water. Before we reject or blame the HT crops and Glyphosate theoretically, we should have enough data to do so.
|Brett Comment left 20th January 2010 15:03:35|
Yes. There is certainly data showing how HT crops and glyphosate have adversely impacted soil microbial communities and have increased the presence of toxic fungi in the soil, not to mention potential leaching into ground water and bodies of water nearby. Other populations of microorganisms are affected as well. Glyphosate is definitely not 'benign' in this sense at all. There are groups of researchers investigating these impacts, perhaps more than what tends to be heard of in the US, due to the pro-GM lobby. We will be reporting on this in the near future. Stay tuned.
|John Wilson Comment left 19th January 2010 17:05:31|
It would be interesting to know what is happening to the fertility of the soil in which HT GM crops are grown. I suspect that yearly applications of glyphosate herbicides will gradually reduce soil fertility. There is evidence that mycorrhizal fungi, nitrogen fixing bacteria and earthworms are harmed by Roundup. Many other vital soil organisms are also likely to be adversely affected by contact with glyphosate herbicide chemicals. Monsanto claim that glyphosate is deactivated on contact with the soil. However there is evidence that glyphosate can stop binding to soil particles and move through the soil in solution.
Is anyone investigating this aspect of GM farming ?
|Jimmy Comment left 26th January 2010 14:02:55|
Why are proponents of organic agriculture concerned with hebicide resisitant weeds. They don't pose any greater threat than any other weed that routinely infests and reduces their yields.
Also the Organic Food Centre report bases its herbicide use for non-GM on rates in areas free from HT crops. As these tend to be the areas with very low or no weed pressure (hence HT technology isn't necessary) there is a massive underestimation of the increases directly caused by GM.
Finally, what sort of measurement of herbicide use is 'pounds of herbicide' used? Some are highly toxic and will kill a human on exposure (largely now banned) whereas others are less toxic than the coffee you drink or the toothpaste you brush your teeth in.
[offensive paragraph edited out]
|Richard Comment left 9th November 2012 13:01:07|
Jimmy is correct.
The LD50 toxicology data on something like 2,4 D mentioned in the above article is almost 10x worse than glyphosate. (LD50 of ~5000mg/kg vs. ~600mg/kg).
2,4 D use went down as glyphosate increased with Round-up ready crops.
Even if we used 2x as much glyphosate as 2,4 D, since 2,4 D is fatal at levels 10x less, we would still be 5x safer with glyphosate. It will be interesting to see if facts are deemed an "offensive paragraph" and this is edited out.
|George Comment left 25th November 2012 19:07:23|
I think you're missing the point Jimmy and Richard. The fact that 2,4 D is more toxic than Glyphosate is a premise for why it shouldn't be used. The point of the article seems that any use of glyphosate will result in harming the environment and people and that it isn't as benign as once thought. Is it safer compared to 2,4D, I don't doubt it, but this doesn't make Glyphosate 'safe' either. What's wrong with herbicide-resistant weeds? Are you joking? Maybe the fact they resist herbicides making them highly difficult to kill requiring more herbicides?