Data presented at a conference by Dr Charles Benbrook analyse pesticide use on GM and non-GM equivalent crops over the first 16 years of use, from 1996 to 2011. The analysis is based on widely accepted USDA data.

Crops considered are herbicide-tolerant corn, soy, and cotton; Bt corn varieties engineered to resist corn rootworm and European corn borer pests; and Bt cotton.

Benbrook’s new data challenge “conventional wisdom” on GM crops and pesticide use. Dozens of papers in peer-reviewed journals assert GM crops reduce pesticide use, either based on no data or proprietary surveys of “representative fields”. Scientists repeat the claim in professional meetings and policy venues and lack of independent analyses by government or university experts allows the claim to go unchallenged, despite growing evidence to the contrary.
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Implications of GM crop cultivation at large spatial scales
Presentation given in Bremen, Germany, June 14-15, 2012
By Charles Benbrook, PhD, Center for Sustaining Agriculture and Natural Resources, Washington State University, Pullman, WA
Summary by GMWatch

1. Increased herbicide use on GM RR soy over time:
*Use of glyphosate on GM RR soy acres INCREASED from 0.69 pounds per acre in 1996 to 1.56 in 2011.
*Use of other herbicides on GM RR soy acres DECREASED from 0.20 pounds per acre in 1996 to 0.12 in 2011.
*Use of all herbicides on GM RR soy acres INCREASED from 0.89 pounds per acre in 1996 to 1.68 in 2011.
*Use of all herbicides on non-GM soy acres DECREASED from 1.19 pounds per acre in 1996 to 0.96 in 2011.

2. Non-sustainability of GM soy:
The differential between herbicides used on GM RR soy and non-GM soy is growing, showing that GM RR soy is increasing the use of herbicides over time whereas non-GM soy is decreasing herbicide use. In 1996 GM RR soy needed 0.30 pounds per acre less herbicide than non-GM soy. But in 2011 GM RR soy needed 0.73 pounds per acre more herbicide than non-GM soy.

3. Increased herbicide use on GM herbicide-tolerant (HT) crops as compared with non-GM crops in 2011:
*0.73 pounds per acre more in the case of soy
*0.41 pounds per acre more in corn
*0.86 pounds per acre more in cotton.

4. 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.

5. Bt crop impacts on insecticide use and overall GM crop impacts 1996-2011:
*Bt corn and cotton have REDUCED chemical insecticide spray use by 124 million pounds (56 million kgs).
*GM crops have INCREASED overall pesticide use by 403 million pounds (183 million kgs). This means an additional 0.25 pounds (0.28 kg/ha) of active ingredient for every GM trait acre.

6. Increase in rate (pounds per acre) of glyphosate applications on GM glyphosate-tolerant corn, cotton and soy:
*Corn: increase of 54% between 1996 and 2010
*Cotton: increase of 206% between 1996 and 2010
*Soy: increase of 96.6% between 1996 and 2006.

[GMWatch comment: The above data should not surprise us as Benbrook points out, the pesticide industry owns the seed industry:
*Changes in US patent and intellectual property law created unprecedented profit opportunities.
*The pesticide industry took over the seed industry, in the late 1980s-1990s.]

7. Bt corn for European corn borer insecticide (endotoxin) production compared with chemical insecticide sprays displaced:
*0.12 pounds chemical insecticide sprays applied per acre for ECB control on non-GM corn in 2010
*MON 810 produces 0.18 pounds endotoxins per acre
*Bt 11 produces 0.25 pounds endotoxin per acre
*MON 89034, Cry1A.105 plus Cry2Ab2 produces 0.6 pounds of two endotoxins per acre (5 X the amount of chemical insecticides displaced).

8. Bt corn for rootworm control insecticide (endotoxin) production compared with chemical insecticide sprays displaced:
*0.19 pounds chemical insecticide sprays applied per acre for rootworm control on non-GM corn 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 the amount of chemical insecticides displaced).

9. Chemical insecticides displaced in fields planted to Monsanto-Dow AgroSciences SmartStax corn:
*Total expression of Bt proteins is 3.73 pounds per acre: 12 X more than the chemical insecticide sprays displaced (0.31 pounds active ingredients)

[GMWatch comment: The above data confirm that GM Bt crops do not reduce or eliminate insecticides, but simply change the way that pesticides are used, from sprayed on, to built in.]

10. HT technology has dramatically accelerated the emergence and spread of resistant weeds:
*Over 14 million acres (5.6 million ha) in the US are now infested with glyphosate-resistant weeds.
*22 weeds now resistant to glyphosate, and more than a dozen pose economic threat to US farmers.
*Some weeds have evolved resistance via two or more mechanisms of resistance.
*44% of multiple herbicide-resistant weeds have appeared since 2005.

11. Prospects for weed management for US farmers:
*Few, if any, viable chemical options will remain.
*Non-chemical options are costly and require significant system changes return to rotations, heavy tillage to bury weed seeds, planting of cover crops, and mechanical cultivation and/or hand weeding.
*“It is very unlikely that new herbicides with new modes of action will be available within ten to 15 years.” MDK Owen, 2011, J. Consumer Protection and Food Safety: 85-89.

12. Industry “solutions”:
*Industry push to market 2,4-D, dicamba, and paraquat HT crops.
*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 US.
*Studies link 2,4-D exposure to reproduction problems, spontaneous abortions, birth defects, and non-Hodgkin’s lymphoma.   

13. Emerging issues in the wake of GM crop technology:
*Corporate control over seed industry and germplasm profits now drive breeding decisions in the US, not problem-solving.
*Passive role of US 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.

14. Lack of independent research on GM traits and systems:
*GM seed “technology agreements” contain language to 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.”

Background to the new data

The new data is an update of Benbrook’s previous reports of 2004 and 2009. The 2009 report found that herbicide use had increased 383 million pounds (173 million kgs) in first 13 years of GM crop use, due to herbicide-tolerant crops. A modest reduction in chemical insecticide spray applications due to Bt crops (down 64.2 million pounds or 29.1 million kg) was swamped by an overall increase in pesticide use of 318 million pounds (144 million kg).