---
title: "Genetically modified food controversies"
chunk: 14/21
source: "https://en.wikipedia.org/wiki/Genetically_modified_food_controversies"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:17:47.717639+00:00"
instance: "kb-cron"
---

The US has no legislation governing the relationship among mixtures of farms that grow organic, conventional, and GM crops. The country relies on a "complex but relaxed" combination of three federal agencies (FDA, EPA, and USDA/APHIS) and states' common law tort systems to manage coexistence. The Secretary of Agriculture convened an Advisory Committee on Biotechnology and 21st Century Agriculture (AC21) to study coexistence and make recommendations about the issue. The members of AC21 included representatives of the biotechnology industry, the organic food industry, farming communities, the seed industry, food manufacturers, State governments, consumer and community development groups, the medical profession, and academic researchers. AC21 recommended that a study assess the potential for economic losses to US organic farmers; that any serious losses lead to a crop insurance program, an education program to ensure that organic farmers put appropriate contracts in place and that neighboring GMO farmers take appropriate containment measures. Overall the report supported a diverse agriculture system supporting diverse farming systems.
The EU implemented regulations specifically governing co-existence and traceability. Traceability has become commonplace in the food and feed supply chains of most countries, but GMO traceability is more challenging given strict legal thresholds for unwanted mixing. Since 2001, conventional and organic food and feedstuffs can contain up to 0.9% of authorised modified material without carrying a GMO label. (any trace of non-authorised modification is cause for a shipment to be rejected). Authorities require the ability to trace, detect and identify GMOs, and the several countries and interested parties created a non-governmental organization, Co-Extra, to develop such methods.

=== Chemical use ===

==== Pesticides ====
Pesticides destroy, repel or mitigate pests (an organism that attacks or competes with a crop). A 2014 meta-analysis covering 147 original studies of farm surveys and field trials, and 15 studies from the researchers conducting the study, concluded that adoption of GM technology had reduced chemical pesticide use by 37%, with the effect larger for insect-tolerant crops than herbicide-tolerant crops. Some doubt still remains on whether the reduced amounts of pesticides used actually invoke a lower negative environmental effect, since there is also a shift in the types of pesticides used, and different pesticides have different environmental effects. In August 2015, protests occurred in Hawaii over the possibility that birth defects were being caused by the heavy use of pesticides on new strains of GM crops being developed there. Hawaii uses 17 times the amount of pesticides per acre compared to the rest of the US.

===== Herbicides =====
The development of glyphosate-tolerant (Roundup Ready) plants changed the herbicide use profile away from more persistent, higher toxicity herbicides, such as atrazine, metribuzin and alachlor, and reduced the volume and harm of herbicide runoff. A study by Chuck Benbrook concluded that the spread of glyphosate-resistant weeds had increased US herbicide use. That study cited a 23% increase (.3 kilograms/hectare)  for soybeans from 1996 to 2006, a 43% (.9 kg/ha) increase for cotton from 1996 to 2010 and a 16% (.5 kg/ha) decrease for corn from 1996 to 2010. However, this study came under scrutiny because Benbrook did not consider the fact that glyphosate is less toxic than other herbicides, thus net toxicity may decrease even as use increases. Graham Brookes accused Benbrook of subjective herbicide estimates because his data, provided by the National Agricultural Statistics Service, does not distinguish between genetically modified and non-genetically modified crops. Brookes had earlier published a study that found that the use of biotech crops had reduced the volume and environmental impact of herbicide and other pesticides, which contradicted Benbrook. Brookes stated that Benbrook had made "biased and inaccurate" assumptions.
The environmental impact of herbicides is estimated in several studies through the Environmental Impact Quotient (EIQ); however, some authors criticize the use of this tool, considering it an inadequate and methodologically flawed measure for accurately assessing the environmental effects of pesticides and, in particular, herbicides. In the study by Kniss (2017), which did not use the EIQ but instead adopted an approach based on risk quotients for acute and chronic toxicity, the evolution of herbicide use intensity and relative toxicity in the United States over approximately 25 years was analyzed across six crops. Herbicide use intensity increased in all evaluated crops, including faster growth in some non–genetically modified crops. Despite this, the toxicity associated with herbicides did not increase proportionally: chronic toxicity decreased in soybean and rice, while acute toxicity showed reductions in corn/maize, soybean, cotton, and rice. In the most recent year evaluated in the study (2014–2015), glyphosate accounted for approximately 26% of applications in corn, 43% in soybean, and 45% in cotton, but was responsible for only 0.1, 0.3, and 3.5% of the chronic toxicity risk in these crops, respectively, due to its relatively low toxicological profile.

===== Insecticides =====
A claimed environmental benefit of Bt-cotton and maize is reduced insecticide use. A PG Economics study concluded that global pesticide use was reduced by 286,000 tons in 2006, decreasing pesticidal environmental impact by 15%. Another study concluded that insecticide use on cotton and corn during the years 1996 to 2005 fell by 35,600,000 kilograms (78,500,000 lb) of active ingredient, roughly equal to the annual amount applied in the European Union. A Bt cotton study in six northern Chinese provinces from 1990 to 2010 concluded that it halved the use of pesticides and doubled the level of ladybirds, lacewings and spiders and extended environmental benefits to neighbouring crops of maize, peanuts and soybeans.