the impacts of genetically engineered crops on pesticide use in the u.s. the first sixteen years...
Post on 14-Dec-2015
229 Views
Preview:
TRANSCRIPT
THE IMPACTS OF GENETICALLY ENGINEERED CROPS ON PESTICIDE USE IN THE U.S. THE FIRST SIXTEEN YEARS
Charles Benbrook, PhD
Center for Sustaining Agriculture and Natural ResourcesWashington State University Pullman, WA
Implications of GM-Crop Cultivation
at Large Spatial Scales
Bremen, GermanyJune 14-15, 2012
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
Perc
en
t of
Acre
s
HT CornHT SoyaHT Cotton
Bt Corn for CRW
Bt Corn for ECBBt Cotton
Roundup Ready (RR) Technology Largely Solved Difficult Weed Management Challenges in the Mid-1990s
1995 20022.7 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 USDA-NASS ‘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 glyphosate-resistant 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 ModelProjections
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 ModelProjections
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
1996199
7199
8199
9200
0200
1200
2200
3200
4200
5200
6200
7200
8200
9201
02011F
Crop Year Rates per Acre
NASS Average All Herbicides
1.17
1.18
1.08
1.04
1.05
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
1.10
1.00
1.28
1.22
1.20
1.21
1.48
1.51
1.56
1.61
1.66
1.68
Conventional Varieties
1.19
1.22
1.13
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 -0.30 -0.23 -0.03 0.13 0.11 0.10 0.34 0.25 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 Rate in
1996(pounds /
acre)
Glyphosate Rate in
2010(pounds /
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.
Bt Corn Gene Expression Levels
Bt Corn Gene Expression Levels per Plant Tissue: Major Events and Products
Product Name EventCry Protein
Plant Stage
Shootb conc. (ug/g
dw)
Root conc.
(ug/g dw)Syngenta Agrisure® CB BT 11 Cry1Ab mature
Monsanto YieldGard® Corn Borer MON 810 Cry1Ab 2 wk post-pollination
Monsanto YieldGard® Rootworm MON 863 Cry3Bb1 forage, 90 DAP 130 136
Monsanto YieldGard VT™ Rootworm MON 88017 Cry3Bb1 forage, R4-5 40 50
Monsanto Genuity™ VT Double PRO™ MON 890345 Cry1A.105Cry2Ab2
forage, R4-5forage, R4-5
1829
2016
DowAgrosciences Pioneer Hi-Bred Herculex® I TC1507 Cry1F forage, R4-5 7.69 5.32
Dow AgroSciences Pioneer Hi-Bred Herculex® RW
DAS 59122-7Cry34Ab1Cr35Ab1
forage, R4-5forage, R4-5
16837.1
85.418.3
Monsanto Genuity™SmartStax™, DowAgrosciences SmartStax™
MON 88017MON 89034TC 1507DAS 59122-7
Cry3Bb1Cry1A.105Cry2Ab2Cry1FCry34Ab1Cr35Ab1
forage, R4-5forage, R4-5forage, R4-5forage, R4-5forage, R4-5forage, R4-5
4819299
15733.6
652118
5.9784.618.9
Impacts of Bt Corn on Endotoxin Production
Impacts of Bt Corn on Endotoxin Production
Bt Corn Cry Protein Quantities per Land Area: Major Events and Products
Product Name EventCry Protein
Plant Stage
Plants/acre
Cry/acreg
(lb/acre)Syngenta Agrisure® CB BT 11 Cry1Ab mature 26,500 0.252
Monsanto YieldGard® Corn Borer MON 810 Cry1Ab2 wk post-pollination 32,000 0.183
Monsanto YieldGard® Rootworm MON 863 Cry3Bb1forage, 90 DAP 32,000 1.732
Monsanto YieldGard VT™ Rootworm MON 88017 Cry3Bb1 forage, R4-5 32,000 0.551
Monsanto Genuity™ VT Double PRO™ MON 890345 Cry1A.105Cry2Ab2
forage, R4-5forage, R4-5
32,00032,000
0.2420.3550.597
DowAgrosciences Pioneer Hi-Bred Herculex® I TC1507 Cry1F forage, R4-5 32,000 0.097
Dow AgroSciences Pioneer Hi-Bred Herculex® RW
DAS 59122-7Cry34Ab1Cr35Ab1
forage, R4-5forage, R4-5
32,00032,000
2.0420.45
2.492
Monsanto Genuity™SmartStax™, DowAgrosciences SmartStax™
MON 88017MON 89034TC 1507DAS 59122-7
Cry3Bb1Cry1A.105Cry2Ab2Cry1FCry34Ab1Cr35Ab1
forage, R4-5forage, R4-5forage, R4-5forage, R4-5forage, R4-5forage, R4-5
32,00032,00032,00032,00032,00032,000
0.6720.256
0.360.1121.9180.4123.73
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 Monsanto-Dow 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 CropEndotoxin ProductionCompared to Natural Levelsof Bt in the Soil
?Natural Bt
Soil Microorganis
ms
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 2012Few, 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 auxin-resistant 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 risksPaul 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 SystemsGE 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, science-driven 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
top related