GM crops to reduce pesticide use and “reverse the Silent Spring scenario”

Claims

Note: “Pesticides” include insecticides, herbicides, and fungicides

Monsanto (now Bayer) employee Edward E. Debus said in a mid-1990s conference presentation in which he seems to speak for the company: “We predict that growers who planted Roundup Ready soybeans in 1996 will reduce herbicide use by up to one-third and experience improved weed control.” ((Debus EE (1996 or 1997; undated document). Benefits of biotechnology – A United States case study. The 3rd J1RCAS Symposium: The 4th International Symposium on the Biosafety Results of Field Tests. https://www.jircas.go.jp/sites/default/files/publication/intlsymp/intlsymp-5_191-198.pdf )) 

In 1998 Monsanto spokesman Dan Verakis claimed that GM crops could reduce the volume of herbicides and other pesticides used in farming and thereby “reverse the Silent Spring scenario”.((Brookes M and Coghlan A, (1998). Live and let live. New Scientist, 31 Oct. https://www.newscientist.com/article/mg16021585-200-live-and-let-live/ )) 

In 1999 the then-Monsanto CEO Robert Shapiro boasted that GM Bt insecticidal crops had triggered an “80 percent reduction in insecticide use in cotton crops alone in the United States”.((BBC News (1999). Sci/Tech: Bob Shapiro: In his own words. 8 Oct. http://news.bbc.co.uk/1/hi/sci/tech/468147.stm ))

In 2000 Matt Ridley, journalist and former chairman of the subsequently-collapsed Northern Rock bank, argued that of 12 US regions surveyed by the US Department of Agriculture (USDA), seven were using less pesticide due to deploying GM Bt crops. He concluded: “GM reduces pesticide use: If you are against GM, you are in favour of more pesticides.” ((Matt Ridley (2000). GM crops could take the moral high ground. Daily Telegraph, 29 Feb. p24. ))

Results

Herbicide-tolerant GM crops: Increase in chemical use

An analysis by the GMO industry group ISAAA found that by 2014, over 99% percent of cultivated GM crops globally were engineered to tolerate one or more herbicides, or to express an insecticide, or both.((International Service for the Acquisition of Agri-biotech Applications (ISAAA) (2014). ISAAA Brief 49-2014: Executive Summary: Global Status of Commercialized Biotech/GM Crops: 2014. Ithaca, NY. http://www.isaaa.org/resources/publications/briefs/49/executivesummary/default.asp  See “PPT slides and tables”, slide 5. ))

The widespread adoption of GM glyphosate-tolerant crops in North and South America has led to large increases in the use of Roundup and other glyphosate-based herbicides (see Figure 2). In the USA, GM herbicide-tolerant (mostly to glyphosate herbicides such as Roundup) crops led to an estimated 239 million kg increase in herbicide use between 1996 and 2011, compared with what would have been used if the same acres had been planted to non-GM crops.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Env Sci Eur 24, article no 24. https://enveurope.springeropen.com/articles/10.1186/2190-4715-24-24 )) Nearly 67% of agricultural glyphosate herbicide use since 1974 occurred between 2005 and 2014, as GM glyphosate-tolerant crops became widespread. Global glyphosate use is reported to have risen almost 15-fold since GM glyphosate-tolerant crops were introduced in 1996.((Benbrook CM (2016). Trends in glyphosate herbicide use in the United States and globally. Envi Sci Eur 28, article no 3. https://enveurope.springeropen.com/articles/10.1186/s12302-016-0070-0 ))

Data from the Food and Agriculture Organisation (FAO) and Health Canada show that herbicide sales in Canada increased by 234% between 1994 and 2020 (see Figure 1).((United Nations Food and Agriculture Organisation, Statistics Division (2015). The UN FAO reports that 21.9 million kilograms of herbicides were sold in Canada in 1994. http://faostat3.fao.org/. The Health Canada numbers are available for 1995 onwards:  Health Canada (2021). Pest control Products Sales Reports. http://www.hc-sc.gc.ca/cps-spc/pest/registrant-titulaire/reporting-declaration/_sales-ventes/index-eng.php Data from the UN FAO and Health Canada were collected by Canadian Biotechnology Action Network (CBAN), and are presented in chart form in: CBAN (2024). Pesticides. https://cban.ca/gmos/issues/pesticides/ )) GM herbicide-tolerant crops were first commercially grown in Canada in 1995.((ISAAA (2020. Canada celebrates 25 years of GM approvals. https://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=18018 ))

Figure 1. Herbicide sales in Canada 1990–2020

In Brazil, GM herbicide-tolerant soy was authorised in 2003. Overall pesticide use increased 1.6-fold between 2000 and 2012. Use on soybeans increased 3-fold, prompting scientists to state, “The adoption of GM crops in Brazil has led to an increase in pesticide use with possible increases in environmental and human exposure and associated negative impacts.” ((Almeida VES de et al (2017). Use of genetically modified crops and pesticides in Brazil: growing hazards. Ciência & Saúde Coletiva 22(10):3333-3339. http://www.scielo.br/j/csc/a/tjr9r6KFWxPMqzxM3jKDBPJ/?lang=en ))

In Argentina, GM herbicide-tolerant soy was authorised in 1996. Estimated glyphosate use rates per hectare (ha) per crop year rose from 2.83 kg/ha in 2000 to 4.45 kg/ha in 2014.((Benbrook C (2016). Env Sci Eur 28(1):3. Supplemental Table S22. http://www.enveurope.com/content/28/1/3/abstract. Glyphosate rate per crop year cited in this paper is from Benbrook CM (2005). Rust, resistance, run down soils, and rising costs – Problems facing soybean producers in Argentina. AgBioTech InfoNet. Appendix 4. http://web.archive.org/web/20110103061717/https://www.biosafety-info.net/file_dir/2916248854c16c65ea.pdf. These figures are extrapolated in turn from data on herbicide sales per year in Argentina collected by pesticide industry association CASAFE. See: CASAFE (archived version of 2007). Estadística. https://web.archive.org/web/20070925135443/http://www.casafe.org.ar/mediciondemercado.html

 )) Glyphosate spraying on GM soy has been linked with increased rates of cancers and birth defects in people.((Vazquez MA et al (2017). International Journal of Clinical Medicine 8(20):73. http://www.scirp.org/journal/PaperInformation.aspx?PaperID=74222&#abstract ; Campana H et al (2010). Arch Argent Pediatr 108:409–417. http://www.ncbi.nlm.nih.gov/pubmed/21132229 ; Avila-Vazquez M et al (2018). J Envi Protection 9(3):241. http://www.scirp.org/journal/PaperInformation.aspx?PaperID=83267&#abstract )) Glyphosate has been classified as a probable human carcinogen.((Guyton K et al (2015). The Lancet Oncology 16(5):490-491. http://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045%2815%2970134-8.pdf ))

In the US, the small initial reduction in chemical insecticide sprays due to GM Bt insecticidal crops was dwarfed by the large increase in herbicide use due to GM herbicide-tolerant crops. This increase has been driven by the spread of glyphosate-resistant weeds.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Environ Sci Eur 24(24). doi:10.1186/2190-4715-24-24. See also Figures 1–6 in the current article. )) These have evolved in response to over-use of the herbicide on glyphosate-tolerant crops – only weeds that have developed resistance to the herbicide survive and pass on their genes. Farmers spray ever-increasing amounts of glyphosate until no amount of the chemical will kill these “superweeds”. A weed expert estimated in 2015 that due to the adoption of GM glyphosate-tolerant crops, one-third of all US field cropland was infested with glyphosate-resistant weeds.((Richard Allison (2015). How glyphosate-resistant weeds will infest all US crops by 2020. Farmers Weekly, 19 Oct. https://www.fwi.co.uk/arable/glyphosate-resistant-weeds-will-infest-us-crops-2020  ))

A 2013 study analysed FAO data on agricultural productivity in the US and Western Europe over the last 50 years, focusing on maize, canola, and wheat. The study found that North American farming systems used in staple crop production – based on GM seeds in the case of maize and canola – showed a trend of lowering yields and increasing pesticide use, compared to Western Europe’s almost entirely non-GM farming systems. Also, both herbicide and insecticide use were increasing in the US relative to Western Europe.((Heinemann JA, Massaro M, Coray DS, Agapito-Tenfen SZ, Wen JD. Sustainability and innovation in staple crop production in the US Midwest. Int J Agric Sustain. June 2013:1–18. http://www.tandfonline.com/doi/full/10.1080/14735903.2013.806408#.UrnaHfYnuUc ))

An updated analysis of FAO data conducted for the New York Times in a 2016 article titled, “Doubts about the promised bounty of genetically modified crops”, confirmed that these trends were continuing.((Hakim D (2016). Doubts about the promised bounty of genetically modified crops. New York Times, 29 Oct. https://www.nytimes.com/2016/10/30/business/gmo-promise-falls-short.html ))

“Solution” to glyphosate resistant weeds: Multiple herbicide tolerance

GMO developer companies’ solution to glyphosate-resistant superweeds has been to develop “stacked-trait” GM crop varieties, resistant to multiple herbicides. The US Environmental Protection Agency (EPA) approved a new combination herbicide, Dow’s (now Corteva) Enlist Duo, in 2014.((US EPA (2023). Registration of Enlist One and Enlist Duo. https://www.epa.gov/ingredients-used-pesticide-products/registration-enlist-one-and-enlist-duo#:~:text=Enlist%20Duo%2C%20which%20contains%202,both%20products%20in%2034%20states. )) Enlist Duo is composed of glyphosate plus 2,4-D, an ingredient of the defoliant Agent Orange. It is marketed in tandem with Dow’s maize and soybean seeds that are genetically engineered to tolerate glyphosate, 2,4-D, dicamba, and multiple other herbicides.((USDA (2014). Dow AgroSciences Petitions (09-233- 01p, 09-349-01p, and 11-234-01p) for Determinations of Nonregulated Status for 2,4-D-Resistant Corn and Soybean Varieties: Final Environmental Impact Statement — August 2014. https://www.aphis.usda.gov/brs/aphisdocs/24d_feis.pdf ; APHIS (2014). Dow AgroSciences LLC; Determination of nonregulated status of herbicide resistant corn and soybeans. 22 Sept. https://www.federalregister.gov/documents/2014/09/22/2014-22409/dow-agrosciences-llc-determination-of-nonregulated-status-of-herbicide-resistant-corn-and-soybeans ))

In 2014 the US Department of Agriculture approved Dow’s multi-herbicide-tolerant GM soybean, engineered to tolerate being sprayed with glyphosate, glufosinate, and 2,4-D,((Gillam C (2011). Dow takes on Monsanto with new biotech soybean. Reuters, 22 Aug. Archived by GMWatch: https://www.gmwatch.org/en/news/archive/2011/13376 ))  as well as 2,4-D-tolerant soybeans and maize.((Beyond Pesticides (2014). USDA approves 2,4-D-tolerant (GE) crops. 19 Sept. https://beyondpesticides.org/dailynewsblog/2014/09/usda-approves-24-d-tolerant-ge-crops/ ; APHIS (2014). Record of decision. Dow AgroSciences petitions (09-233-01p, 09-349-01p, and 11-234-01p) for determination of nonregulated status for 2,4-D resistant corn and soybean varieties. 16 Sept. https://www.aphis.usda.gov/brs/aphisdocs/24d_rod.pdf ))

In 2015 the US Department of Agriculture approved Monsanto’s Xtend GM soybeans and cotton, engineered to tolerate dicamba and glyphosate.((Gillam C (2015). USDA approves Monsanto’s new GMO soybeans, cotton. Reuters, 15 Jan. https://www.reuters.com/article/idUSL1N0UU1YT/ )) The USDA predicted that dicamba use would increase 88-fold and 14.5-fold for soybeans and cotton respectively, compared to the then current levels.((US Department of Agriculture (USDA) (2014). Monsanto Petitions (10-188-01p and 12-185-01p) for Determinations of Nonregulated Status for Dicamba-Resistant Soybean and Cotton Varieties: Final Environmental Impact Statement. Riverdale, MD: US Department of Agriculture. http://www.aphis.usda.gov/brs/aphisdocs/dicamba_feis.pdf ))

US government data confirms a steep increase in the use of dicamba((USGS (2021). Estimated annual agricultural pesticide use: Pesticide use maps – dicamba. Use by year and crop. https://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2019&map=DICAMBA&hilo=L )) and 2,4-D((USGS (2021). Estimated annual agricultural pesticide use: Pesticide use maps – 2,4-D. Use by year and crop. https://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2019&map=24D&hilo=L&disp=2,4-D)) in the years since GM crops tolerant to these herbicides were approved. However, weeds have already developed resistance to these herbicides,((LeClere S et al (2018). Proceedings of the National Academy of Sciences of the United States of America 115(13). https://www.pnas.org/doi/10.1073/pnas.1712372115 ; Martin H (2013). Herbicide resistant weeds. Ontario Ministry of Agriculture, Food and Rural Affairs. http://www.omafra.gov.on.ca/english/crops/facts/01-023.htm ; Unglesbee E (2021). Glufosinate-resistant pigweed. DTN Progressive Farmer. 17 Feb. https://www.dtnpf.com/agriculture/web/ag/crops/article/2021/02/17/glufosinate-resistant-palmer ; Brown HC (2021). Attack of the superweeds. New York Times. 18 Aug. https://www.nytimes.com/2021/08/18/magazine/superweeds-monsanto.html  )) overtaking US farms.((Brown HC (2021). Attack of the superweeds. New York Times. 18 Aug. https://www.nytimes.com/2021/08/18/magazine/superweeds-monsanto.html)) Dicamba is the focus of lawsuits brought by farmers whose crops have been destroyed by the herbicide drifting off-target.((Consumernotice.org (2021). Dicamba lawsuits. https://www.consumernotice.org/legal/dicamba-lawsuits/ ))

Keeping farmers tied to a pesticide treadmill benefits the big GMO developer companies – Bayer (owner of Monsanto), Corteva (formerly DowDuPont), Syngenta, and BASF – which are also pesticide companies.((Neumeister L (2023). New genome techniques (NGT) – a risky corporate distraction from real sustainable solutions. Foodwatch. p7. https://www.foodwatch.org/fileadmin/-INT/pesticides/2023-01-30_foodwatch_Pesticides_and_NGTSs.pdf ))

Herbicide use increased after introduction of the relevant GM herbicide-tolerant seeds

US Geological Survey (USGS) data on national pesticide use show that the use of many herbicides sharply increased after the introduction of the relevant GM herbicide-tolerant seeds, as shown in the figures below.((USGS (2023). Pesticide National Synthesis Project: Estimated annual agricultural pesticide use. https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php ))

Figure 2. Glyphosate use in the US after GM glyphosate-tolerant soybean, maize, and cotton varieties were introduced in 1996((Figure from USGS (as above). https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php  For the 1996 date of the introduction into the US of GM glyphosate-tolerant soybeans, maize, and cotton, see: Dill GM (2005). Glyphosate-resistant crops: History, status and future. Pest Manag Sci 61(3):219-24. doi: 10.1002/ps.1008 ; and Benbrook C (2016). Trends in glyphosate herbicide use in the United States and globally. Environ Sci Eur 28(1):3. doi: 10.1186/s12302-016-0070-0 ))

Figure 3. 2,4-D use in the US after GM 2,4-D tolerant crops were approved in 2014, introduced into fields in 2015((Figure from USGS (as above). https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php For the 2014 date of the approval and 2015 date of the planting of Dow’s Enlist GM 2,4-D and glyphosate-tolerant maize and soybeans and accompanying herbicide, see: Gillam C (2014). USDA grants approval to Dow’s Enlist GMO corn and soybeans. Reuters, 18 Sept. https://www.reuters.com/article/2014/09/17/agriculture-dow-enlist-idUSL1N0RI38B20140917/ ; and US EPA (updated 2023). Registration of Enlist One and Enlist Duo. https://www.epa.gov/ingredients-used-pesticide-products/registration-enlist-one-and-enlist-duo ))

Figure 4. Glufosinate use in the US after the introduction of GM glufosinate-tolerant cotton (2004) and soybeans (2009)((Figure from USGS (as above). https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php For the 2004 date of the introduction of GM glufosinate-tolerant cotton, see Aulakh JS et al (2011). Weed management and cotton yield under two row spacings in conventional and conservation tillage systems utilizing conventional, glufosinate-, and glyphosate-based weed management systems. Weed Technology 2011 25:542–547. https://www.ars.usda.gov/ARSUserFiles/60100500/csr/ResearchPubs/price/aulakh_11a.pdf  For the 2009 date of the introduction of Bayer’s GM glufosinate-tolerant LibertyLink soybeans, see Farm Progress (2009). Bayer: LibertyLink soybeans coming. 22 Jan. https://www.farmprogress.com/soybean/bayer-libertylink-soybeans-coming ))

Figure 5. Dicamba use in the US after the introduction of GM dicamba-tolerant crops (soy, cotton, and maize) in 2016((Figure from USGS (as above). https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php For the 2016 date of the introduction of GM dicamba-tolerant crops, see: Dodson L et al. (2021). Adoption of genetically engineered dicamba-tolerant cotton seeds is prevalent throughout the United States. USDA, 6 Jul. https://www.ers.usda.gov/amber-waves/2021/july/adoption-of-genetically-engineered-dicamba-tolerant-cotton-seeds-is-prevalent-throughout-the-united-states/ ; Wechsler SJ et al (2019). The use of genetically engineered dicamba-tolerant soybean seeds has increased quickly, benefiting adopters but damaging crops in some fields. 1 Oct. https://www.ers.usda.gov/amber-waves/2019/october/the-use-of-genetically-engineered-dicamba-tolerant-soybean-seeds-has-increased-quickly-benefiting-adopters-but-damaging-crops-in-some-fields/ ; Winterbottom J (2016). USDA regulators clear two GM corn traits from Monsanto, Syngenta. Reuters, 24 Mar. https://www.reuters.com/article/us-usa-grains-regulation-idUSKCN0WQ013/ ))

Bt crops and insecticides: Early promise, later failure

The introduction of GM Bt crops in North America in 1996 initially led to a small reduction in the use of sprayed-on insecticides. This was swamped, however, by much larger increases in herbicide use due to GM herbicide-tolerant crops. By around 2010, the increase in herbicide use exceeded the reduction in insecticide use by about 7%, compared with what would have been the case if the same area had been planted to non-GM crops.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Env Sci Eur 24, article no 24. https://enveurope.springeropen.com/articles/10.1186/2190-4715-24-24 ))

The over-reliance on GM Bt and GM herbicide-tolerant crops triggered the emergence and spread of resistant insects and weeds, which by around 2010 had locked farmers onto a pesticide treadmill that continues to run faster and faster.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Env Sci Eur 24, article no 24. https://enveurope.springeropen.com/articles/10.1186/2190-4715-24-24 ))

Claims that GM Bt crops have reduced insecticide use – for example, in a much-cited paper published in 2014 by Klümper and Qaim((Klümper W, Qaim M (2014). A meta-analysis of the impacts of genetically modified crops. PLoS ONE 9(11). http://dx.doi.org/10.1371/journal.pone.0111629 )) – held true only for the first few years of cultivation, for the following reasons:

• The data are mostly from the early years of Bt crops, before pests developed resistance.((Tabashnik BE et al (2008). Insect resistance to Bt crops: Evidence versus theory. Nat Biotechnol. 26:199–202. doi:10.1038/nbt1382 ; Rensburg JBJ (2007). First report of field resistance by the stem borer, Busseola fusca (Fuller) to Bt-transgenic maize. Afr J Plant Soil. 24:147-151. http://www.eko.org.ee/gmo/images/stories/research/filed_resistance_to_bt_maize.pdf ; Huang F et al (2007). Resistance of sugarcane borer to Bacillus thuringiensis Cry1Ab toxin. Entomol Exp Appl. 124:117-123. http://agribiotech.free.fr/Huang_2007%20-%20Cry1Ab%20toxin%20-%20Bt%20resistant%20management.pdf ; Keim B (2014). Voracious worm evolves to eat biotech corn engineered to kill it. Wired.com. March. http://www.wired.com/2014/03/rootworm-resistance-bt-corn/ ; Gassmann AJ et al (2011). Field-evolved resistance to Bt maize by Western corn rootworm. PLoS ONE 6:e22629. doi:10.1371/journal.pone.0022629 ; Associated Press (2011). Monsanto shares slip on bug-resistant corn woes. Bloomberg Businessweek, 29 Aug. Archived by GMWatch https://www.gmwatch.org/en/latest-listing/1-news-items/13390 ; Gray M (2014). Western corn rootworm resistance to Bt corn confirmed in more Illinois counties. Aces News, 7 Apr. http://www.aces.uiuc.edu/news/stories/news5903.html ; Gallium C (2013). GMO corn failing to protect fields from pest damage – report. Reuters, 28 Aug. http://www.reuters.com/article/2013/08/28/usa-gmo-corn-rootworm-idUSL2N0GT1ED20130828 ; Unglesbee E (2017). Worm rebellion continues: Bollworm populations threaten Bt cotton again this year. DTN Progressive Farmer, 20 Jul. https://www.dtnpf.com/agriculture/web/ag/news/crops/article/2017/07/20/bollworm-populations-threaten-bt ; Farias JR, Andow DA, Horikoshi RJ, et al (2014). Field-evolved resistance to Cry1F maize by Spodoptera frugiperda (Lepidoptera: Noctuidae) in Brazil. Crop Prot. 64:150-158. doi:10.1016/j.cropro.2014.06.019 ; Dively GP et al (2016). Field-evolved resistance in corn earworm to Cry proteins expressed by transgenic sweet corn. PLOS One, 30 Dec. https://doi.org/10.1371/journal.pone.0169115 )) This resistance has forced farmers to return to spraying chemical insecticides.((Kranthi KR, Stone GD (2020) Long-term impacts of Bt cotton in India. Nat Plants 6:188–196. https://doi.org/10.1038/s41477-020-0615-5 )) Indeed, some never stopped. According to one study, bollworm resistance to GM Bt cotton has not caused crop failure in the US because “insecticides have been used from the outset” to control the pest.((Tabashnik BE et al (2008). Nat Biotechnol 26:199–202. http://www.ncbi.nlm.nih.gov/pubmed/18259177 )) In 2020 the US Environmental Protection Agency (EPA) proposed phasing out many Bt maize and some Bt cotton varieties within 3–5 years due to concerns about resistant pests.((US EPA (2020). Proposal to improve Lepidopteran resistance management for Bt plant-incorporated protectants. https://www.regulations.gov/docket/EPA-HQ-OPP-2019-0682 ; Unglesbee E (2020). Bt on the chopping block. DTN Progressive Farmer, 29 Sept. https://www.dtnpf.com/agriculture/web/ag/crops/article/2020/09/29/epa-proposes-phasing-dozens-bt-corn ))
• Even when Bt toxins temporarily succeed in controlling the target pest, secondary pests can move into the ecological niche. In the US, the Western bean cutworm has increased in GM Bt maize fields.((Dorhout DL, Rice ME (2010). Intraguild competition and enhanced survival of western bean cutworm (Lepidoptera: Noctuidae) on transgenic Cry1Ab (MON810) Bacillus thuringiensis corn. J Econ Entomol. 103:54–62. http://www.bioone.org/doi/abs/10.1603/EC09247?prevSearch=&cookieSet=1 Pearson H (2006). Transgenic cotton drives insect boom. Nature. July. doi:10.1038/news060724-5 ; Wang S, Just DR, Pinstrup-Andersen P (2008). Bt-cotton and secondary pests. Int J Biotechnol. 10:113–121. http://www.inderscience.com/info/inarticle.php?artid=18348 ; Goswami B (2007). Making a meal of Bt cotton. Infochange. https://web.archive.org/web/20131025021527/http://infochangeindia.org/other/features/making-a-meal-of-bt-cotton.html?Itemid= . Published September ; The Economic Times (India) (2007). Bug makes meal of Punjab cotton, whither Bt magic? 2 Sept. Archived by GMWatch http://www.gmwatch.org/latest-listing/46-2007/7640 ; Rohini RS, Mallapur CP, Udikeri SS (2009). Incidence of mirid bug, Creontiades biseratense (Distant) on Bt cotton in Karnataka. Karnataka J Agric Sci. 22:680–681. https://www.researchgate.net/publication/264305181_Incidence_of_mirid_bug_Creontiades_biseratense_Distant_on_Bt_cotton_in_Karnataka )) In India and China, Bt cotton was initially effective in suppressing the target pest, the bollworm. But secondary pests that are resistant to Bt toxin, especially mirids and mealy bugs, soon took its place.((Pearson H (2006). Transgenic cotton drives insect boom. Nature. July. doi:10.1038/news060724-5 ; Wang S, Just DR, Pinstrup-Andersen P (2008). Bt-cotton and secondary pests. Int J Biotechnol. 10:113–121. http://www.inderscience.com/info/inarticle.php?artid=18348 ; Goswami B (2007). Making a meal of Bt cotton. Infochange. https://web.archive.org/web/20131025021527/http://infochangeindia.org/other/features/making-a-meal-of-bt-cotton.html?Itemid= . Published September ; The Economic Times (India) (2007). Bug makes meal of Punjab cotton, whither Bt magic? 2 Sept. Archived by GMWatch http://www.gmwatch.org/latest-listing/46-2007/7640 ; Rohini RS, Mallapur CP, Udikeri SS (2009). Incidence of mirid bug, Creontiades biseratense (Distant) on Bt cotton in Karnataka. Karnataka J Agric Sci. 22:680–681. https://www.researchgate.net/publication/264305181_Incidence_of_mirid_bug_Creontiades_biseratense_Distant_on_Bt_cotton_in_Karnataka )) Studies from China published in 2010 show that GM Bt cotton was already failing under the onslaught of secondary pests.((Zhao JH, Ho P, Azadi H (2010). Benefits of Bt cotton counterbalanced by secondary pests? Perceptions of ecological change in China. Env Monit Assess. 173:985-994. doi:10.1007/s10661-010-1439-y ; Lu Y, Wu K, Jiang Y, et al (2010). Mirid bug outbreaks in multiple crops correlated with wide-scale adoption of Bt cotton in China. Science. 328:1151-1154. doi:10.1126/science.1187881  ))
• GM Bt toxin is itself an insecticide and the amount contained in GM Bt plants is far more than the amount of sprayed insecticide it is meant to displace.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Env Sci Eur 24, article no 24. https://enveurope.springeropen.com/articles/10.1186/2190-4715-24-24 )) Also, since GM Bt crops were first introduced, there has been a trend to replace GM plants expressing only one Bt toxin with GM plants expressing multiple (2–6) Bt toxins (stacked events) simultaneously. Therefore the total amount of Bt toxins expressed in recent years versus the early years of Bt crops is multiplied by a factor of 2–6.(( Bøhn T (2018). Criticism of EFSA’s scientific opinion on combinatorial effects of ‘stacked’ GM plants. Food and Chemical Toxicology 111: 268-274. https://www.sciencedirect.com/science/article/abs/pii/S0278691517306907 ; For the number of Bt traits stacked into one crop variety (up to 8, as at 30 Jan 2024): ISAAA (2020). Pocket K no 42: Stacked traits in biotech crops. https://www.isaaa.org/resources/publications/pocketk/42/ )) This increase has proven necessary to make the insecticidal toxins work in the face of evolved resistance in targeted pests.  
• GM Bt insecticidal toxins are not benign. They can harm wildlife, including insects helpful to farmers,((Rosi-Marshall EJ et al (2007). Toxins in transgenic crop byproducts may affect headwater stream ecosystems. Proc Natl Acad Sci USA 104: 16204-8. http://www.ncbi.nlm.nih.gov/pubmed/17923672 ; Hilbeck A et al (1998). Toxicity of Bacillus thuringiensis Cry1Ab toxin to the predator Chrysoperla carnea (Neuroptera: Chrysopidae). Environ Entomol. 27(5):1255-1263. https://academic.oup.com/ee/article-abstract/27/5/1255/2395221?redirectedFrom=fulltext ; Hilbeck A et al (1999). Prey-mediated effects of Cry1Ab toxin and protoxin and Cry2A protoxin on the predator Chrysoperla carnea. Entomol Exp Appl. 91:305–316. http://onlinelibrary.wiley.com/doi/10.1046/j.1570-7458.1999.00497.x/abstract ; Hilbeck A et al (1998). Effects of transgenic Bt corn-fed prey on immature development of Chrysoperla carnea (Neuroptera: Chrysopidae). Environ Entomol. 27(2):480–487. https://academic.oup.com/ee/article-abstract/27/2/480/2464645 Séralini GE et al (2007). New analysis of a rat feeding study with a genetically modified maize reveals signs of hepatorenal toxicity. Arch Environ Contam Toxicol. 52:596–602. https://pubmed.ncbi.nlm.nih.gov/17356802/ de Vendomois JS et al (2009). A comparison of the effects of three GM corn varieties on mammalian health. Int J Biol Sci. 2009;5:706–26. http://www.ncbi.nlm.nih.gov/pubmed/20011136 ; Trabalza-Marinucci M et al (2008). A three-year longitudinal study on the effects of a diet containing genetically modified Bt176 maize on the health status and performance of sheep. Livest Sci 113:178–190. doi:10.1016/j.livsci.2007.03.009 ; Fares NH, El-Sayed AK (1998). Fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes. Nat Toxins. 6(6):219-233. http://www.ncbi.nlm.nih.gov/pubmed/10441029. ; El-Shamei ZS et al (2012). Histopathological changes in some organs of male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 8(10):684–696. https://www.academia.edu/3405345/Histopathological_Changes_in_Some_Organs_of_Male_Rats_Fed_on_Genetically_Modified_Corn_Ajeeb_YG_.  ; Gab-Alla AA et al (2012). Morphological and biochemical changes in male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 8(9):1117–1123. https://www.academia.edu/3138607/ )) and can have toxic effects on mammals that eat them.((Séralini GE et al (2007). New analysis of a rat feeding study with a genetically modified maize reveals signs of hepatorenal toxicity. Arch Environ Contam Toxicol. 52:596–602. https://pubmed.ncbi.nlm.nih.gov/17356802/ de Vendomois JS et al (2009). A comparison of the effects of three GM corn varieties on mammalian health. Int J Biol Sci. 2009;5:706–26. http://www.ncbi.nlm.nih.gov/pubmed/20011136 ; Trabalza-Marinucci M et al (2008). A three-year longitudinal study on the effects of a diet containing genetically modified Bt176 maize on the health status and performance of sheep. Livest Sci 113:178–190. doi:10.1016/j.livsci.2007.03.009 ; Fares NH, El-Sayed AK (1998). Fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes. Nat Toxins. 6(6):219-233. http://www.ncbi.nlm.nih.gov/pubmed/10441029. ; El-Shamei ZS et al (2012). Histopathological changes in some organs of male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 8(10):684–696. https://www.academia.edu/3405345/Histopathological_Changes_in_Some_Organs_of_Male_Rats_Fed_on_Genetically_Modified_Corn_Ajeeb_YG_.  ; Gab-Alla AA et al (2012). Morphological and biochemical changes in male rats fed on genetically modified corn (Ajeeb YG). J Am Sci. 8(9):1117–1123. https://www.academia.edu/3138607/ )) The Bt toxin they contain is different, structurally and in its biological effects, from the natural Bt sprayed by organic and conventional farmers – having been engineered by Monsanto to be a “super toxin”.((Latham J (2017). Have Monsanto and the biotech industry turned natural Bt pesticides into GMO “super toxins”? Independent Science News, 9 Oct. https://www.independentsciencenews.org/environment/have-monsanto-and-the-biotech-industry-turned-natural-bt-pesticides-into-gmo-super-toxins/ ; Latham JR et al (2017). The distinct properties of natural and GM cry insecticidal proteins. Biotechnology and Genetic Engineering Reviews 33(1): 62-96. https://doi.org/10.1080/02648725.2017.1357295  ))
• Since the early 2000s, highly toxic chemical neonicotinoid insecticide seed treatments have been used on Bt and non-Bt seeds alike – but this is ignored by studies claiming that Bt crops reduce pesticide use. A 2015 study by Douglas and Tooker found that neonicotinoid use on US-grown soy and maize – crops that were and are overwhelmingly GMO((USDA (2022). Charts of note. https://www.ers.usda.gov/data-products/charts-of-note/charts-of-note/?topicId=a2d1ab41-13b3-48b5-8451-688d73507ff4 )) – increased rapidly between 2003 and 2011.((Douglas MR, Tooker JF (2015). Large-scale deployment of seed treatments has driven rapid increase in use of neonicotinoid insecticides and preemptive pest management in US field crops. Envi Sci & Tech 49(8):5088–5097. http://dx.doi.org/10.1021/es506141g ))
• While the volumes of neonicotinoids applied are low, their high toxicity means that the expansion in their use has had serious adverse effects on beneficial insects and other wildlife – and resistance in pests is already being documented,((Matsuda K et al (2020). Neonicotinoid insecticides: Molecular targets, resistance, and toxicity. Annual Review of Pharmacology and Toxicology 60:241-255. https://doi.org/10.1146/annurev-pharmtox-010818-021747  )) pointing to issues of environmental safety and sustainability.
• A 2025 review confirmed that contrary to early promises, GM crops have increased agriculture’s dependence on pesticides rather than reducing it. Drawing on data from four GM crops – Bt cotton, herbicide-tolerant (HT) soybean, HT and/or Bt maize, and HT canola, the researchers traced the surge in chemical use over three decades. The researchers explain this outcome using the Jevons paradox, an economic theory that dates back to 1865. British economist William Stanley Jevons argued that efficiency in resource use often leads to more, not less, consumption. ((Flachs A et al (2025). GM crops and the Jevons Paradox: Induced innovation, systemic effects and net pesticide increases from pesticide-decreasing crops. Journal of Agrarian Change. DOI: 10.1111/joac.70006. https://www.researchgate.net/publication/390797835_GM_Crops_and_the_Jevons_Paradox_Induced_Innovation_Systemic_Effects_and_Net_Pesticide_Increases_From_Pesticide-Decreasing_Crops))

“Halo effect” of Bt maize

In 2010 a media article reported research findings that planting Bt maize had a “halo effect”, shielding neighbouring non-GM maize by protecting it against the European corn borer pest and suppressing populations of the pest. The article said in the Midwest, non-Bt acres had “experienced yield savings without the cost of Bt technology fees, and thus received more than half the benefits from growing Bt corn”.((Penn State University (2010). GM crop benefits nonmodified crop by killing pests. Lancaster Farming, 16 Oct. ))

The study was published in the journal Nature, which published an editorial headed, “GM maize offers windfall for conventional farms”.((Milton J (2010). GM maize offers windfall for conventional farms. Nature, 7 Oct. https://www.nature.com/articles/news.2010.523 ))

The study said, “Areawide suppression of the primary pest Ostrinia nubilalis (European corn borer) is associated with Bt maize use. Cumulative benefits over 14 years are an estimated $3.2 billion for maize growers in Illinois, Minnesota, and Wisconsin, with more than $2.4 billion of this total accruing to non-Bt maize growers.”((Hutchison WD et al (2010). Areawide suppression of European Corn Borer with Bt maize reaps savings to non-Bt maize growers. Science 330(6001):222–225. DOI: 10.1126/science.1190242 ))

But by 2015 Bt maize’s “halo” was fading. Under the headline, “GM crop loses effectiveness”, the News and Observer reported on new study findings that – “consistent with predictions made almost 20 years ago that had been largely ignored” – the corn earworm pest had developed resistance to the Bt toxin Cry1Ab: “In the late 1990s, Cry1Ab reduced both the number and size of corn earworm larvae and the size of the larvae, compared to non-Bt corn. But… Cry1Ab now has little or no effect on number or size of larvae compared to non-Bt corn.” ((The News and Observer (Raleigh, North Carolina) (2015). GM crop loses effectiveness. 8 Jun. The study referred to is: Reisig DD, Reay-Jones FPF (2015). Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) growth by transgenic corn expressing Bt toxins and development of resistance to Cry1Ab. Environmental Entomology 44(4):1275–1285. https://doi.org/10.1093/ee/nvv076 ))

GM Bt cotton in India

Some studies have reported that GM Bt cotton reduced chemical insecticide spraying in India.((Qaim M, Zilberman D (2003). Yield effects of genetically modified crops in developing countries. Science 299(5608): 900-902. http://www.sciencemag.org/content/299/5608/900 ; Kathage J, Qaim M (2012). Economic impacts and impact dynamics of Bt (Bacillus thuringiensis) cotton in India. PNAS 109(29): 11652-11656. http://www.ncbi.nlm.nih.gov/pubmed/22753493  )) However, these studies focused on early short-term impacts before pests became resistant to Bt toxins and ignored other major changes in Indian agriculture, such as irrigation and fertiliser use, according to a long-term analysis by internationally renowned experts.

The experts concluded that while initially, “Bt cotton did make a positive contribution in India” by reducing predations by the American bollworm, “the technology’s benefits have been modest and largely ephemeral… Bt seeds’ positive effects on spraying were fleeting. Countrywide yields have not improved in 13 years, and Indian cotton farmers today are spending more per hectare on insecticide than they did before Bt began to spread.” ((Kranthi KR, Stone GD (2020) Long-term impacts of Bt cotton in India. Nat Plants 6:188–196. https://doi.org/10.1038/s41477-020-0615-5 ))

Will new GM crops reduce pesticide use?

The European Commission has claimed that new GM techniques (“new genomic techniques” or NGTs) such as gene editing can reduce the use of pesticides in agriculture by enabling the development of more resilient plants. It has used this claim to justify its proposal to remove certain NGT plants from the requirements of the EU’s GMO regulations (risk assessment, full traceability, and labelling).((European Commission (2023). Remarks by Commissioner Stella Kyriakides at the Agrifish Council – New Genomic Techniques. 25 Jul. https://ec.europa.eu/commission/presscorner/detail/en/speech_23_4004 ))

However, according to a report by the European Commission’s Joint Research Centre (JRC), out of the new GM plants that were classified as close to commercialisation, the largest trait group – six out of 16 plants – was herbicide-tolerant.((Parisi C, Rodriguez Cerezo E (2021). Current and future market applications of new genomic techniques. Current and future market applications of new genomic techniques. Publications Office of the European Union, Luxembourg. ISBN 978-92-76-30206-3. doi:10.2760/02472. https://publications.jrc.ec.europa.eu/repository/handle/JRC123830 . The graphic representation of the data is at https://datam.jrc.ec.europa.eu/datam/mashup/NEW_GENOMIC_TECHNIQUES/ )) These GM plants will continue the trajectory of older-style GM herbicide-tolerant crops, of increasing herbicide use.((Benbrook C (2012). Impacts of genetically engineered crops on pesticide use in the US – The first sixteen years. Environmental Sciences Europe 24. http://www.enveurope.com/content/24/1/24 ; Perry ED et al (2016). Genetically engineered crops and pesticide use in US maize and soybeans. Science Advances 2(8). https://www.science.org/doi/10.1126/sciadv.1600850 ; USGS (as above). https://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php ))

Will new GM techniques like gene editing offer crops that are resistant to pests and diseases, thereby reducing pesticide use? A scientific analysis suggests not, at least for the foreseeable future. The analysis examined the EU’s sustainable development goals (SDGs), including pesticide reduction, linked them with relevant plant traits, and reviewed existing research and field trials with gene-edited crop plants for evidence that their intended traits were able to fulfil the sustainability goals.

One of the two traits that the researchers focused on was resistance to fungal pathogens, a trait that could reduce pesticide use. They found that no new GM plants with resistance to multiple fungal pathogens – which alone could confer resilient disease resistance and thus reduce fungicide use – are close to commercialisation. They concluded that “developing new plants with modified traits will not be sufficient to reach food security or adaption to climatic changes in a short time frame”.((Hüdig M et al (2022). Genome editing in crop plant research—alignment of expectations and current developments. Plants 11(2): 212. https://www.mdpi.com/2223-7747/11/2/212/htm  ))

A report by the non-profit organisation Foodwatch investigated the pesticide reduction claim for new GMOs and found it baseless. The report found that:

• Almost all pests, weeds, and diseases can be prevented by a diverse crop rotation.
• Even if new GM disease-resistant varieties are produced, the necessary development and testing could take decades. So new GM techniques cannot provide quick solutions to these problems.
• Almost 80% of the EU’s pesticide use comprises herbicides and fungicides, and there are no GM solutions available or in development that could substantially reduce these uses.

The report says, “When it comes to pesticide reduction in the European Union, the potential of these genetic engineering technologies seems to be currently nearly zero.” ((Neumeister L (2023). New genome techniques (NGT): A risky corporate distraction from real sustainable solutions. Foodwatch, 31 Jan. https://www.foodwatch.org/fileadmin/-INT/pesticides/2023-01-30_foodwatch_Pesticides_and_NGTSs.pdf ))

Companies

GM herbicide-tolerance traits and crops have been developed by Monsanto (now Bayer), Pioneer Hi Bred and Dow (both now Corteva), Syngenta, and BASF. GM Bt traits and crops have been developed by Syngenta, Bayer, Pioneer Hi Bred, Monsanto, BASF, and Dow and DuPont (both now Corteva).

Patents

GM Bt trait and crop patents are dominated by Syngenta, Bayer, Pioneer Hi Bred, Monsanto, BASF, Dow, and DuPont.((Patents search on lens.org. As at 24 Jan 2024. https://www.lens.org/lens/search/patent/list?q=(Bt%20toxin)%20AND%20Cry%20AND%20plants&p=0&n=10&s=date_published&d=%2B&f=false&e=false&l=en&authorField=author&dateFilterField=publishedDate&orderBy=%2Bdate_published&presentation=false&preview=true&stemmed=true&useAuthorId=false&patentStatus.must=active&patentStatus.must=pending )) GM herbicide-tolerant trait and crop patents are dominated by Monsanto, Pioneer Hi Bred, Syngenta, BASF, and Dow.((Patents search on lens.org. As at 24 Jan 2024. https://www.lens.org/lens/search/patent/list?q=herbicide%20AND%20tolerance%20AND%20plants&p=0&n=10&s=date_published&d=%2B&f=false&e=false&l=en&authorField=author&dateFilterField=publishedDate&orderBy=%2Bdate_published&presentation=false&preview=true&stemmed=true&useAuthorId=false&patentStatus.must=active&patentStatus.must=pending ))

Patents on glyphosate-tolerant soybeans

From the 1990s, Monsanto had owned the patents on the GM Roundup Ready trait in GM glyphosate-tolerant soybeans, the most widely planted GM crop globally. But the last Monsanto and Bayer patents protecting glyphosate-tolerant Roundup Ready soybeans expired in 2015. The authors of an analysis commented, “This opens up a very big market for generic soybean.”((Arias ACR et al (2017). Patents and genetically modified soybean for glyphosate resistance. World Patent Information 48:47–51. https://www.sciencedirect.com/science/article/abs/pii/S0172219016300503 ))

Patents on multi-herbicide-tolerance

The emergence of glyphosate-resistant weeds means that GM plants that are only tolerant to glyphosate are no longer commercially appealing. This has led to companies patenting methods for genetically engineering crops with tolerance to other and multiple herbicides. For example, Monsanto has an active patent on dicamba and glyphosate-tolerance in GM soybeans.((US 10604767 B2. Haplotypes associated with improved dicamba tolerance and glyphosate tolerance in transgenic soybean plants. https://www.lens.org/lens/patent/102-387-001-606-600/frontpage?l=en  )) Bayer has a patent on a GM soybean engineered to tolerate isoxaflutole as well as glyphosate.((US 8592650 B2. Elite event EE-GM3 and methods and kits for identifying such event in biological samples. https://www.lens.org/lens/patent/097-742-222-468-293/fulltext?l=en  ))

A patent search for “Dow + herbicide + tolerance + plants” on the lens.org patents database, restricted to active and pending status, brings up several thousand patents,((Patents search on lens.org. As at 24 Jan 2024. https://www.lens.org/lens/search/patent/list?q=Dow%20AND%20herbicide%20AND%20tolerance%20AND%20plants&p=0&n=10&s=date_published&d=%2B&f=false&e=false&l=en&authorField=author&dateFilterField=publishedDate&orderBy=%2Bdate_published&presentation=false&preview=true&stemmed=true&useAuthorId=false&patentStatus.must=active&patentStatus.must=pending)) including a Dow/Corteva-owned patent on genes conferring tolerance to 2,4-D and other types of herbicide.((US 2011/0124503 A1. Novel herbicide resistance genes. https://www.lens.org/lens/patent/164-635-579-924-33X/fulltext?l=en ))

The mixtures of herbicides and other chemicals that GM herbicide-tolerant plants are designed to be grown with are also patented: for example, “drift reduction adjuvants” intended to prevent Dow’s Enlist herbicides from drifting off-target;((US 11737455 B2. Drift reduction adjuvants and methods of using the same. https://www.lens.org/lens/patent/175-865-745-675-387/frontpage?l=en )) and pesticide mixtures designed as “tank mixes” for farmers to spray.((US 2020/0296964 A1. Pesticidal compositions and methods of use thereof. https://www.lens.org/lens/patent/063-759-906-575-943/fulltext?l=en ))

New GM techniques and patents

Will gene editing and other new GM techniques open up the patent ownership landscape for GM herbicide-tolerant plants? It seems unlikely. A search for active and pending patents relating to “herbicide + tolerance + gene + editing + plants” turns up over 12,000 records, with the field being dominated by Pioneer Hi Bred (Corteva) and Bayer/Monsanto.((Patents search on lens.org. As at 31 Jan 2024. https://www.lens.org/lens/search/patent/list?q=herbicide%20AND%20tolerance%20AND%20gene%20AND%20editing%20AND%20plants&p=0&n=10&s=date_published&d=%2B&f=false&e=false&l=en&authorField=author&dateFilterField=publishedDate&orderBy=%2Bdate_published&presentation=false&preview=true&stemmed=true&useAuthorId=false&patentStatus.must=active&patentStatus.must=pending )) However, as with patents on older-style GM plants, in many cases herbicide tolerance traits are not the primary focus of the patent but are included as optional “extras” in plants primarily engineered to express other traits.

An analysis of the value of sales of the four largest pesticide/seed companies (Bayer, Syngenta, Corteva, and BASF) by product type reveals that the sales value of pesticides outweighs that of seeds.((Neumeister L (2023). New genome techniques (NGT): A risky corporate distraction from real sustainable solutions. Foodwatch, 31 Jan. p7. https://www.foodwatch.org/fileadmin/-INT/pesticides/2023-01-30_foodwatch_Pesticides_and_NGTSs.pdf )) These pesticide-manufacturing companies are also the main developers of seeds produced with new GM techniques. This suggests that they will not abandon their main revenue stream by producing seeds that thrive under reduced agrochemical use – even if such seeds were technically possible to develop, which remains unproven.

Author: Claire Robinson. Reviewer: Jonathan Matthews. Scientific reviewers: Anonymous PhD; Dr Ray Seidler. 

---