유전자조작(GM) 곡물은 농약 사용량을 감소시킨다는 고장난 레코드처럼 계속 되풀이되는 주장과 정반대로 오히려 글리포세트(라운드업) 내성 잡초의 증가로 제초제의 사용량이 늘어나서 실제 농약 사용량이 늘어났다는 연구결과가 나왔습니다.
유기농센터(The Organic Center)의 수석 과학자인 Charles M Benbrook 박사는 미 농무부 자료를 분석하여 미국에서 1996년~2011년 16년 동안 유전자조작 곡물 재배와 살충제 사용량의 영향에 관한 연구 결과를 피어리뷰 학술지인
Charles M Benbrook 박사는 1979년부터 미국 워싱턴 DC에서 농업정책, 과학, 규제에 관한 이슈를 다루었으며, Council for Environmental Quality, executive director of the subcommittee of the House Committee on Agriculture, and executive director of the Board on Agriculture of the National Academy of Sciences 등에서 활동했습니다.
1999년부터 지속적으로 유전자조작 곡물의 재배와 살충제 사용량에 대한 분석을 해왔습니다. (http://www.nlpwessex.org/docs/benbrook.htm)
2009 Report (3.7m pdf)
2004 Report (2.8m pdf)
2003 Report (869k pdf)
2001 Report (457k pdf)
2001 Report (458k pdf)
1999 Report (280k pdf)
Evidence of the Magnitude and Consequences of the Roundup Ready Soybean Yield Drag from University-Based Varietal Trials in 1998
* 미국에서 1996–2011년 16년 동안 유전자조작 곡물의 살충제 사용 영향
1996~2011년 16년 동안 미국에서 제초제 내성 작물 재배로 인한 제초제 사용량은 2억3900만kg 증가하였으며, Bt 곡물은 살충제 사용량을 5600만kg 감소시켰다. 따라서 농약사용량은 1억8300만 kg 늘어났다.(증가율 7%)
이러한 증가율을 유전자조작 옥수수와 콩에 사용하는 2,4-D의 사용량에 적용해보면, 농약 2,4-D 농약 사용량이 50%나 증가했음을 알 수 있다.
Impacts of genetically engineered crops on pesticide use in the U.S. — the first sixteen years
출처 : Environmental Sciences Europe 2012, 24:24 doi:10.1186/2190-4715-24-24
Charles M Benbrook (firstname.lastname@example.org)
http://www.enveurope.com/content/pdf/2190-4715-24-24.pdf (원문 첨부파일)
Genetically engineered, herbicide-resistant and insect-resistant crops have been remarkable commercial successes in the United States. Few independent studies have calculated their impacts on pesticide use per hectare or overall pesticide use, or taken into account the impact of rapidly spreading glyphosate-resistant weeds. A model was developed to quantify by crop and year the impacts of six major transgenic pest-management traits on pesticide use in the U.S. over the 16-year period, 1996–2011: herbicide-resistant corn, soybeans, and cotton; Bacillus thuringiensis (Bt) corn targeting the European corn borer; Bt corn for corn rootworms; and Bt cotton for Lepidopteron insects.
Herbicide-resistant crop technology has led to a 239 million kilogram (527 million pound)
increase in herbicide use in the United States between 1996 and 2011, while Bt crops have
reduced insecticide applications by 56 million kilograms (123 million pounds). Overall,
pesticide use increased by an estimated 183 million kgs (404 million pounds), or about 7%.
Contrary to often-repeated claims that today’s genetically-engineered crops have, and are
reducing pesticide use, the spread of glyphosate-resistant weeds in herbicide-resistant weed management systems has brought about substantial increases in the number and volume of herbicides applied. If new genetically engineered forms of corn and soybeans tolerant of 2,4-D are approved, the volume of 2,4-D sprayed could drive herbicide usage upward by another approximate 50%. The magnitude of increases in herbicide use on herbicide-resistant hectares has dwarfed the reduction in insecticide use on Bt crops over the past 16 years, and will continue to do so for the foreseeable future.
New US Study Shows GM Crops Increase Use of Herbicides
The latest study published by Washington State University research professor Charles Benbrook finds that the use of herbicides in the production of three genetically modified herbicide-tolerant crops — cotton, soybeans and corn — has actually increased. This counterintuitive finding is based on an exhaustive analysis of publicly available data from the U.S. Department of Agriculture’s National Agriculture Statistics Service. Benbrook’s analysis is the first peer-reviewed, published estimate of the impacts of genetically engineered (GE) herbicide-resistant (HT) crops on pesticide use.
Dr. Charles Benbrook, research professor, WSU Center for Sustaining Agriculture and Natural Resources. Photo courtesy Washington State University. Click image to download hi-resolution version.
In the study, which appeared in the the open-access, peer-reviewed journal “Environmental Sciences Europe,” Benbrook writes that the emergence and spread of glyphosate-resistant weeds is strongly correlated with the upward trajectory in herbicide use. Marketed as Roundup and other trade names, glyphosate is a broad-spectrum systemic herbicide used to kill weeds. Approximately 95 percent of soybean and cotton acres, and over 85 percent of corn, are planted to varieties genetically modified to be herbicide resistant.
“Resistant weeds have become a major problem for many farmers reliant on GE crops, and are now driving up the volume of herbicide needed each year by about 25 percent,” Benbrook said.
The annual increase in the herbicides required to deal with tougher-to-control weeds on cropland planted to GE cultivars has grown from 1.5 million pounds in 1999 to about 90 million pounds in 2011.
Herbicide-tolerant crops worked extremely well in the first few years of use, Benbrook’s analysis shows, but over-reliance may have led to shifts in weed communities and the spread of resistant weeds that force farmers to increase herbicide application rates (especially glyphosate), spray more often, and add new herbicides that work through an alternate mode of action into their spray programs.
This latest study again rocks the GMO industry following on as it does from the recent study out of France showing that Roundup and GM maize could cause cancer.
Herbicide-tolerant and Bt-transgenic crops now dominant U.S. agriculture, accounting for about one in every two acres of harvested cropland, and around 95% of soybean and cotton acres, and over 85% of corn acres.
Over the first six years of commercial use (1996-2001), HT and Bt crops reduced pesticide use by 31 million pounds, or by about 2%, compared to what it likely would have been in the absence of GE crops.
Bt crops have reduced insecticide use by 10-12 million pounds annually over the last decade. From 1996-2011, Bt crops have reduced insecticide use on the three crops by 123 million pounds, or about 28%.
The annual per acre reduction in insecticide use on acres planted to Bt corn and cotton has trended downward since 1996, because of the shift toward lower-dose insecticides and the expansion of Bt corn onto acres that would not likely be treated with an insecticide.
The relatively recent emergence and spread of insect populations resistant to the Bt toxins expressed in Bt corn and cotton has started to increase insecticide use, and will continue to do so in response to recommendations from entomologists to preserve the efficacy of Bt technology by applying insecticides previously displaced by the planting of Bt crops.
Herbicide-tolerant crops worked extremely well in the first few years of use, but over-reliance led to shifts in weed communities and the emergence of resistant weeds that have, together, forced farmers to incrementally –
- Increase herbicide application rates (especially glyphosate),
- Spray more often, and
- Add new herbicides that work through an alternate mode-of-action into their spray programs.
Each of these responses has, and will continue to contribute to the steady rise in the volume of herbicides applied per acre of HT corn, cotton, and soybeans.
HT crops have increased herbicide use by 527 million pounds over the 16-year period (1996-2011). The incremental increase per year has grown steadily from 1.5 million pounds in 1999, to 18 million five years later in 2003, and 79 million pounds in 2009. In 2011, about 90 million more pounds of herbicides were applied than likely in the absence of HT, or about 24% of total herbicide use on the three crops in 2011.
Today’s major GE crops have increased overall pesticide use by 404 million pounds from 1996 through 2011 (527 million pound increase in herbicides, minus the 123 million pound decrease in insecticides). Overall pesticide use in 2011 was about 20% higher on each acre planted to a GE crop, compared to pesticide use on acres not planted to GE crops.
There are now two-dozen weeds resistant to glyphosate, the major herbicide used on HT crops, and many of these are spreading rapidly. Millions of acres are infested with more than one glyphosate-resistant weed. The presence of resistant weeds drives up herbicide use by 25% to 50%, and increases farmer-weed control costs by at least as much.
The biotechnology-seed-pesticide industry’s primary response to the spread of glyphosate-resistant weeds is development of new HT varieties resistant to multiple herbicides, including 2,4-D and dicamba. These older phenoxy herbicides pose markedly greater human health and environmental risks per acre treated than glyphosate. Approval of corn tolerant of 2,4-D is pending, and could lead to an additional 50% increase in herbicide use per acre on 2,4-D HT corn.
Substantial volumes of Bt toxins are produced per acre planted to Bt corn and cotton. The volumes of these toxins produced by the plants on an acre exceed in nearly all cases the volume of insecticides displaced by the planting of a Bt cultivar. For example, Bt corn targeting the corn rootworm and related soil insects expresses one to two pounds of Bt toxins per acre, while displacing about 0.19 pound of insecticide per acre. The first GE crop expressing eight traits, so-called SmartStax corn, produces 3.7 pounds of Bt toxins per acre and displaces around 0.3 pounds of insecticides.
Reductions in pesticide-related environmental and human health risks have been among the benefits thought to be associated with the shift to glyphosate-based HT crops and Bt corn and cotton. Over the last 16 years, there has been dramatic growth in the volumes of both Bt toxins and glyphosate required to bring crops to harvest. The levels of glyphosate and Bt in the ambient environment, animal feed, and food have markedly increased, creating a myriad of new exposure pathways.
Much new research will be required to translate emerging data on higher exposures to glyphosate and Bt toxins into estimates of human, farm and companion animal, and environmental risks.
Important Terms and Definitions
“Pesticide” is the term used by the U.S. EPA, and pest control experts and scientists, to describe any chemical sprayed or applied to control insects, weeds, plant disease, and rodents. “Pesticide” encompasses herbicides, insecticides, fungicides, rodenticides, and fumigants. “Pesticide use” on a given crop refers to the volume of pesticides applied during a production season, either per acre/hectare or across all acres/hectares planted to the crop. Pesticide use is typically measured as the sum of the pounds of herbicides, insecticides, fungicides, and other types of pesticides applied.
“Genetically-engineered (GE) crops” have been transformed to express a novel trait using the tools of molecular biology. The new traits in GE crops are derived from a foreign species that is not sexually compatible with the transformed crop (e.g., a bacterium, a fish, an animal, a tree).
“Herbicide-tolerant (HT) crops” are genetically engineered to withstand the application of specific herbicides over the top of the crop, killing or stunting weed growth, while leaving the crop unharmed.
“Herbicide-resistant weeds” have developed the capacity to withstand or overcome applications of herbicides that once killed or controlled the weed.
“Bt-transgenic (Bt) crops” refer to varieties of corn and cotton genetically engineered to biosynthesize in plant cells one or more protein endotoxins produced by subspecies of the bacterium Bacillus thuriengiensis.
Full Study: gmoevidence.org