Implications of GM-Crop Cultivation
at Large Spatial Scales
Bremen, Germany
June 14-15, 2012
Charles Benbrook, PhD
Center for Sustaining Agriculture
and Natural Resources
Washington State University
Pullman, WA
THE IMPACTS OF GENETICALLY ENGINEERED
CROPS ON PESTICIDE USE IN THE U.S.
THE FIRST SIXTEEN YEARS
Remarkable Commercial Success
Stephen Duke, ARS/University of Mississippi, and Michael
Owen, of Iowa State University on glyphosate,
herbicide-tolerant technology
“…the most rapid adoption of a crop technology in the
history of agriculture.”
“…the most important change in technology in the
history of agriculture.”
Percent of National Acres Planted to
Herbicide-Tolerant (HT) and Bt
Transgenic Crop Varieties, 1996-2011
HT Corn
HT Soya
HT Cotton
Bt Corn for CRW
Bt Corn for ECB
Bt Cotton
Roundup Ready (RR) Technology Largely
Solved Difficult Weed Management
Challenges in the Mid-1990s
1995
2002
2.7 herbicides/acre
1.7 herbicides/acre
Tricky timing
Wide window
Damage from carry over
and/or phytotoxicity
No problems, forgiving
technology
The Creation of a Multi-Billion $$
Seed-Biotech-Pesticide-Industry
• Changes in U.S. patent and intellectual property
law created unprecedented profit opportunities
• The pesticide industry took over the seed
industry, in the late 1980s – 1990s
• In March 1999, DuPont purchased
the remaining shares of Pioneer
Hi-Bred International for $7.7 billion,
an 80% premium over the stock’s
trading value
Conventional Wisdom
?
• Dozens of papers in peer-reviewed journals assert GE
crops reduce pesticide use, either based on no data or
proprietary surveys of “representative fields”
• Prominent scientists repeat the claim in professional
meetings and policy venues
• Lack of independent analyses by government or
university experts allows industry claims to go
unchallenged, despite growing evidence to the
contrary
Analysis based on USDANASS ‘Agricultural
Chemical Use Surveys’.
Calculated pounds
applied per acre planted
to conventional varieties
and GE varieties.
Reported a 122 million
pound (55.3 million kg)
increase 1996 – 2004.
November 2009 report by The
Organic Center.
Herbicide use up 383 million
pounds (173 million kgs) in first 13
years of GE crop use.
Insecticide applications down
64.2 million pounds (29.1 million
kgs).
Overall pesticide use up 318
million pounds (144 million kgs).
Analysis Now Updated Through 2011
• New USDA-NASS pesticide use data released for corn
and cotton and 2010
• Update reflects the enormous impacts of glyphosateresistant weed problems on herbicide use
GE Crop-Pesticide Use Simulation
Model
Linked series of 15 tables in an Excel workbook
Widely accepted USDA data available on:
• Acres planted to maize, soybeans, and cotton
• Percent crop acres planted and not planted to
major GE traits
• Herbicide and glyphosate use rates per acre
• Use rates of insecticides displaced by Bt corn
and cotton
GE Crop-Pesticide Use Simulation
Model
By crop, major GE trait, and year, the model estimates:
• Herbicide use on acres planted to herbicide-tolerant
and non-GE varieties, and hence differences in rates
• Insecticides per acre not applied as a result of
planting Bt corn or cotton
• Impacts of GE traits on pesticide use across all acres
planted to GE crops by year, and from 1996 through
2011
Uncertainties in Model
Projections
?
How weed management systems would have evolved in the
absence of HT technology
Design and efficacy of corn IPM systems for European corn
borer and corn rootworm control if Bt crop technology had
not become available
?
Uncertainties in Model
Projections
Method used to estimate “Other [not glyphosate] Herbicide”
applications on HT acres by crop/year
Supplemental Table 9. Herbicide Use on Conventional and Herbicide-Tolerant (HT) Soybeans, 1996 - 2011
1996
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011F
Crop Year Rates per Acre
NASS Average All Herbicides
1.17
1.18
0.96 1.20
1.17
1.15
1.17
1.42
1.46
1.50
1.55
1.59
1.64
Glyphosate on RR Acres
0.69
0.79 0.90 0.90 0.88 0.85 1.03
1.06
1.09
1.13
1.35
1.39
1.43
1.47
1.52
1.56
Other Herbicides on RR Acres 0.20
0.20 0.20 0.20 0.22
0.15
0.25
0.16
0.11
0.08 0.13
0.12
0.125 0.14
0.14
0.12
All Herbicides on RR Acres
0.89
0.99 1.10
1.10
1.00
1.28
1.22
1.20
1.21
1.51
1.56
1.66
1.68
Conventional Varieties
1.19
1.22
0.97 0.99 0.89 0.94 0.98 0.88 0.88 0.90 0.93 0.87 0.86 0.72
0.96
Difference in Pounds per Acre
Between RR and Conventional
Varieties
1.08
1.13
-0.30 -0.23 -0.03
1.04
0.13
1.05
1.10
0.11
0.10 0.34
0.25
1.48
1.61
0.32 0.33 0.58 0.58 0.69 0.76 0.94
0.73
Estimating the Differences in HT
and Non-HT Herbicide Use
Solve weighted average equation for “Non-HT
Rates”:
Average herbicide use (kg/ha)
= (% Hectare planted HT x HT rate) + (% Hectare
Planted Non-HT x Non-HT rate)
Five variables – 3 known, 1 easy to estimate (“HT Rate”),
so the equation can be solved for fifth variable (“Non-HT
Rate”)
Key Results: 2011 Herbicide Rates
Each acre planted to a HT variety required substantially
more herbicides than acres not planted to HT crops:
• 0.73 pounds per acre more in the case of soybeans
• 0.41 pounds per acre in corn
• 0.86 pounds per acre in cotton
C. Benbrook. 2012 “Impacts of Genetically Engineered Crops on Pesticide Use in
the U.S. – The First Sixteen Years,” Environmental Sciences Europe, Pending.
Impacts of HT Crops on Herbicide
Use: 1996 - 2011
• Herbicide-tolerant (HT) crops have INCREASED
herbicide use by a total or 527 million pounds (239
million kgs)
• HT soybeans account
for 72% of the total
increase in herbicide use
across the three HT crops
Bt Crop Impacts on Insecticide Use and
Overall GE Crop Impacts: 1996 - 2011
• Bt corn and cotton have REDUCED insecticide use
by 124 million pounds (56 million kgs)
• GE crops have INCREASED overall pesticide use by
403 million pounds (183 million kgs)
 Represents, on average, an additional ~0.25
pound (~0.28 kg/ha) of active ingredient for
every GE trait acre
Changes in the Rate per Crop Year
of Glyphosate (Roundup)
Crop and Period
Glyphosate Glyphosate
Rate in
Rate in
1996
2010
(pounds /
(pounds /
acre)
acre)
Total
Increase
(pounds /
acre)
Percent
Change
Average
Annual
Percent
Change in
Period Noted
Corn (1996-2010
0.68
1.05
0.37
54%
3.8%
Cotton (1996-2010)
0.63
1.93
1.3
206%
14.7%
Soybeans (1996-2006)
0.69
0.67
96.6%
9.8%
Note: All use data is from the USDA NASS surveys of pesticide use, and take into account both
changes in the one-time rate of application and the average number of applications per crop year.
Impacts
of Bt Corn
on Endotoxin
Bt Corn Gene
Expression
Levels
Production
Bt Corn Gene Expression Levels per Plant Tissue:
Major Events and Products
Product Name
Event
Cry Protein
Plant Stage
Syngenta Agrisure® CB
BT 11
Cry1Ab
mature
Monsanto YieldGard® Corn Borer
MON 810
Cry1Ab
Monsanto YieldGard® Rootworm
MON 863
Cry3Bb1
2 wk postpollination
forage, 90 DAP
Monsanto YieldGard VT™ Rootworm
MON 88017
Cry3Bb1
Monsanto Genuity™ VT Double PRO™
MON 890345
DowAgrosciences Pioneer Hi-Bred Herculex® I
Shootb conc.
(ug/g dw)
Root conc.
(ug/g dw)
130
136
40
50
Cry1A.105
Cry2Ab2
forage, R4-5
forage, R4-5
forage, R4-5
18
29
20
16
TC1507
Cry1F
forage, R4-5
7.69
5.32
Dow AgroSciences Pioneer Hi-Bred Herculex® RW
DAS 59122-7
Cry34Ab1
Cr35Ab1
forage, R4-5
forage, R4-5
168
37.1
85.4
18.3
Monsanto Genuity™SmartStax™, DowAgrosciences
SmartStax™
MON 88017
MON 89034
TC 1507
DAS 59122-7
Cry3Bb1
Cry1A.105
Cry2Ab2
Cry1F
Cry34Ab1
Cr35Ab1
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
48
19
29
9
157
33.6
65
21
18
5.97
84.6
18.9
Impacts of Bt Corn on Endotoxin
Production
Bt Corn Cry Protein Quantities per Land Area:
Major Events and Products
Product Name
Event
Cry Protein
Plant Stage
Syngenta Agrisure® CB
BT 11
Cry1Ab
Monsanto YieldGard® Corn Borer
MON 810
Cry1Ab
Monsanto YieldGard® Rootworm
Monsanto YieldGard VT™ Rootworm
MON 863
MON 88017
Cry3Bb1
Cry3Bb1
Monsanto Genuity™ VT Double PRO™
MON 890345
Cry1A.105
Cry2Ab2
forage, R4-5
forage, R4-5
DowAgrosciences Pioneer Hi-Bred Herculex® I
TC1507
Cry1F
forage, R4-5
Dow AgroSciences Pioneer Hi-Bred Herculex® RW
DAS 59122-7
Cry34Ab1
Cr35Ab1
forage, R4-5
forage, R4-5
MON 88017
MON 89034
TC 1507
DAS 59122-7
Cry3Bb1
Cry1A.105
Cry2Ab2
Cry1F
Cry34Ab1
Cr35Ab1
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
forage, R4-5
Monsanto Genuity™SmartStax™, DowAgrosciences
SmartStax™
mature
2 wk postpollination
forage, 90 DAP
forage, R4-5
Plants/acre
Cry/acreg
(lb/acre)
26,500
0.252
32,000
32,000
0.183
1.732
32,000
0.551
0.242
0.355
0.597
32,000
32,000
32,000
32,000
32,000
32,000
32,000
32,000
32,000
32,000
32,000
0.097
2.042
0.45
2.492
0.672
0.256
0.36
0.112
1.918
0.412
3.73
Bt Corn for ECB Endotoxin Production
Compared to Insecticides Displaced
• ~0.12 pound insecticides applied per acre for ECB
control in 2010
• MON 810 produces 0.18 pound endotoxins per acre
• Bt 11 produces 0.25 pounds endotoxin per acre
• Dow/Pioneer Herculex TC1507 produces 0.097 pound
per acre
• MON 89034, Cry1A.105 plus Cry2Ab2 produces 0.6
pound of two endotoxins per acre (5-X insecticides
displaced)
Bt Corn for Rootworm Control
Endotoxin Production Compared
to Insecticides Displaced
• ~0.19 pound insecticides applied per acre in 2010
• MON 88017, Cry3Bb1 produces 1.7 pounds endotoxin per
acre
• Dow/Pioneer DAS 59122-7,
Cry34Ab1 plus Cry35Ab1
produces 2.5 pounds
per acre (13-X insecticides
displaced)
On Fields Planted to MonsantoDow AgroSciences SmartStax Corn
• Each plant expresses six different Bt Cry proteins, three
for ECB/Lepidoptera, and three for corn rootworm
(CRW)/Coleoptera control
• Total expression of Bt proteins is
3.73 pounds per acre: 12-times more
than the insecticides displaced
(0.31 pounds active ingredients
[0.12 ECB + 0.19 CRW pounds])
What About Bt Crop
Endotoxin Production
Compared to Natural Levels
of Bt in the Soil
?
Natural Bt Soil
Microorganisms
Bt Cotton
Bt Corn
0.25 g
400 – 1000 g/ha
2,800 – 4,200 g/ha
Bt cotton produces up to 4,000 times more Bt than soil
microorganisms, while Bt corn produces up to 16,800 times
more.
Blackwood, C.B., J.S. Buyer, 2004. “Soil Microbial Communities
Associated with Bt and Non-Bt Corn in Three soils,” J. Environmental
Quality, Vol. 33, pages 832-836
The Resistance Clock
is Ticking
“You guys are three years behind
us. This is exactly what we looked
like three years ago.”
Message to Iowa HT corn-soybean
farmers from Jason Northsworthy,
University of Arkansas weed
scientist, after inspecting row-crop
fields in central Iowa
HT Technology has Dramatically
Accelerated the Emergence and
Spread of Resistant Weeds
• Over 14 million acres (5.6 million ha) in the U.S. are now
infested with glyphosate resistant weeds
• 22 weeds now resistant to glyphosate, and more than a
dozen now pose an economic threat to U.S. farmers
• Some weeds have evolved resistance via two or more
mechanisms of resistance!
David A. Mortensen et al., “Navigating a Critical Juncture for
Sustainable Weed Management,” BioScience, Vol. 62, page 75
Resistance Poses an Ominous
Threat to U.S. Farmers
• 108 biotypes of 38 weed species are simultaneously
resistant to herbicides in 2 or more families of chemistry
 44% of multiple resistant weeds have appeared
since 2005
 Common waterhemp in the U.S. is resistant to
more than 20 currently marketed active ingredients,
including glyphosate, ALS, and PPD herbicides.
David A. Mortensen et al., “Navigating a Critical Juncture for
Sustainable Weed Management,” BioScience, Vol. 62, page 75
Waterhemp Resistant to Five Herbicide
Modes of Action are Expected in 2012
Few, if any, viable chemical options will
remain
Non-chemical options are all costly and
require significant system changes • return to rotations
• use of heavy tillage to bury weed seeds
• planting of cover crops, and
• mechanical cultivation and/or hand
weeding
No Major New Herbicide Mode of
Action Commercialized in 20 Years *
“…It is very unlikely that new herbicides with
new modes of action will be available within
ten to 15 years.”
Michael D.K. Owen, 2011. “Weed resistance development and
management in herbicide-tolerant crops: experiences from the USA,” J.
Consumer Protection and Food Safety, Supplement 1, pages 85-89, doi
\10.1007/s00003-011-0679-2
* Gerwick, “Thirty years of herbicide discovery: surveying the past and
contemplating the future,” Agrow (Silver Jubilee Edition)
So…Industry Push to Market 2,4-D,
Dicamba, and Paraquat HT Crops
High-risk gamble for farmers and public health
Five weed scientists on second-generation HT
crops:
“…we expect that synthetic auxin-resistant
(2,4-D, dicamba) cultivars will be embraced by
growers and planted on rapidly increasing areas in
the US and worldwide over the next 5-10 years.”
David A. Mortensen et al., “Navigating a Critical Juncture for
Sustainable Weed Management,” BioScience, Vol. 62, page 75
…and In Response to Claims that There are “Very
Few” Weeds Resistant to Synthetic Auxins….
“Globally, there are 28 species [resistant to
2,4-D and dicamba], … and at least 2
resistant to both active ingredients.”
“…the potential for synthetic auxinresistant or combined synthetic auxin- and
glyphosate-resistant weeds in transgenic
cropping systems is actually quite high.”
[Emphasis added]
David A. Mortensen et al., “Navigating a Critical Juncture for
Sustainable Weed Management,” BioScience, Vol. 62, page 75
Dramatic Increase Highly Likely
in 2,4-D Use
Supplemental Table 19. C. Benbrook. 2012 “Impacts of Genetically
Engineered Crops on Pesticide Use in the U.S. – The First Sixteen
Years,” Environmental Sciences Europe, Pending.
Basis for Projecting the Increase of 2,4-D
Use on 2,4-D HT Corn (…if approved)
• Dicamba-tolerant corn is not approved
• 2,4-D HT corn adoption peaks at 55%
in 2019
• Average rate of application increases
from 0.35 pound in 2010 to 0.6 pounds
(maximum 1.0 pound rate on label)
• Number of applications increase from
1.1 to 2.3 in 2019 (maximum of 3 allowed
on label)
Drift and Volatilization of 2,4-D and Dicamba
Even without 2,4-D HT crops, 2,4-D is the #1 cause of crop
damage episodes investigated by state departments of
agriculture in the U.S.
2.4-D HT crops will vastly worsen
problems because of higher rates
and applications later in the crop
season, despite the beneficial
impact of the new Dow 2,4-D
formulation
Likely Problems in the Wake of Increases in
Synthetic Auxin Herbicide Use
Multiple studies link 2,4-D applications in
the spring to reproduction problems,
spontaneous abortions and birth defects
Farm workers in California exposed to
2,4-D had a dramatically elevated risk of
non-Hodgkin’s lymphoma (NHL) (odds
ratio = 3.8), with female workers facing
higher risks
Paul K. Mills, Richard Yang, Deborah Riordan, 2005. “Lymphohematopoietic
cancers in the United Farm Workers of America (UFW), 1988-2001,” Cancer Causes
and Controls, Vol. 16, pages 823-830
Emerging Issues in the Wake of GE Crop
Technology
Corporate control over the seed industry and germplasm –
profits now drive breeding decisions in the U.S., not problem
solving
Passive role of the U.S. government in dealing with herbicide
resistance and the collateral damage of HT crops
Erosion of investments in prevention-based IPM and farmer IPM
skill sets
Rapidly growing reliance on systemic delivery of toxins – seed
treatments, insecticides, Bt endotoxins – that alter risk profiles
The Lack of Independent Research on
GE Traits and Systems
GE seed “technology agreements” contain language
to the effect that –
“This seed is for commercial use by
farmers growing crops, and may
not be used for any research
purpose or to compare
performance to other
corn/soybean/cotton varieties.”
Plant Health is Clearly Eroding on
Many Farms
Declining plant health triggered by changes in
genetics, planting densities, and crop management
during the GE crop era
2010 – 11% corn was treated with fungicide (USDA NASS data)
 Less than 1% of corn acres were treated with
fungicides in all previous NASS surveys
Is Corn IPM Obsolete
?
“Within the past 14 years, producers have transitioned
from a traditional IPM paradigm (scouting, use of
thresholds, and rescue treatments) to that of a less
integrated and more insurance-based approach to
insect management…”
Michael E. Gray, 2011. “Relevance of Traditional Integrated Pest Management (IPM)
Strategies for Commercial Corn Producers in a Transgenic Agroecosystem: A Bygone
Era?” J. Agricultural and Food Chemistry, Vol. 59, pages 5852-5858
Eight Reasons Bt Corn Has To Date
Proven Incompatible with IPM
1. Prophylactic treatment not reliant on scouting and
thresholds
2. Inability to target treatments to parts of fields with
populations exceeding economic thresholds
3. Toxin expressed throughout the production season, and not
just when insects are most vulnerable or actively feeding
4. Toxin expressed throughout plant, including tissues that are
not fed upon by a target insect
Eight Reasons Bt Corn Has To Date
Proven Incompatible with IPM
5. The technology is dependent on single, or closely related
toxins, increasing risk of resistance and/or cross-resistance
6. High probability of sub-lethal doses of Bt endotoxins in some
corn plant tissues during parts of the season, increasing
resistance risk
7. Technology marketed as a complete solution, downplaying
the need for other tactics
8. Presence of Bt genes/toxins in most elite corn hybrids denies
farmers the choice of a non-Bt
Vulnerable GE Crops Require Higher-Risk
and High-Cost Seed Treatment
Mixing multiple active ingredients in
seed treatments increases the risk of
resistance emerging in a variety of soil
borne insects and pathogens
Nicotinyl seed treatments likely major
risk factor for honey bee/pollinator
Colony Collapse Disorder (CCD)
Michael E. Gray, 2011. “Relevance of Traditional Integrated Pest Management
(IPM) Strategies for Commercial Corn Producers in a Transgenic Agroecosystem:
A Bygone Era?” J. Agricultural and Food Chemistry, Vol. 59, pages 5852-5858
Lessons From the U.S. Experience with
First-Generation GE Crops
Excessive reliance on single tactics, and one herbicide,
will increase the risk of resistance, lead to more
intensive pesticide use, and raise costs and
environmental impacts.
Resistance management requires an active, sciencedriven government role, with requirements imposed as
mandatory label conditions, backed up by meaningful
enforcement.
Lessons From the U.S. Experience with
First-Generation GE Crops
Expecting too much from GE technology is asking for
trouble
The impacts of GE technology
will be determined by the
overall health of the
agricultural system in which
it is deployed
A Criticl Insight From a Seminal
1997 PNAS Paper
“As spectacular and exciting as biotechnology is, its
breakthroughs have tended to delay our shift to long
term, ecologically based pest management because the
rapid array of new products provide a sense of security
just as did synthetic pesticides at the time of their
discovery in the 1940s.”
Lewis, W.J. et al., 1997. “A total system approach to
sustainable pest management,” Proceedings of the NAS,
Vol. 94, pages 12243-12248