Excerpted from the Environmental Impact of Missouri Crop Production report

  • Farmers have widely adopted genetically modified corn, soybeans and cotton.
  • The adoption of herbicide-resistant crops has led to more herbicide use but a smaller environmental impact.
  • The adoption of insect-resistant crops has led to less insecticide use and a smaller environmental impact.

Two types of genetically modified crops are common in U.S. agriculture: herbicide-tolerant crops and insect-resistant crops.

Missouri producers extensively adopted genetically modified crop varieties during the past two decades. The image below charts the share of Missouri planted corn, soybean and upland cotton acreage that used genetically modified varieties from 2000 to 2017.

Missouri genetically modified variety adoption by crop, 2000–2017

Missouri genetically modified variety adoption by crop, 2000–2017
*All genetically modified varieties
**Missouri-specific cotton acreage data were first released in 2005
Source: USDA Economic Research Service (2017)

Depending on the crop, producers have accepted some biotech traits more than others. The table below summarizes Missouri and U.S. genetically modified variety adoption data for 2017.

Types of genetically modified crop varieties planted in Missouri and U.S., 2017
Insect-resistant (Bt) only2%3%
Herbicide-tolerant only8%12%
Stacked gene varieties81%77%
All genetically modified varieties91%92%
Herbicide-tolerant only87%94%
All genetically modified varieties87%94%
Insect-resistant (Bt) only5%5%
Herbicide-tolerant only36%11%
Stacked gene varieties58%80%
All genetically modified varieties99%96%
Source: USDA Economic Research Service

In some cases, interest in environmental sustainability has encouraged genetically modified crop adoption. Research has measured whether genetically modified crops have enabled growers to apply less herbicide and pesticide. Analysis of a farm-level, commercial dataset from 1998 to 2011 revealed the following observations about the quantity of herbicides used: 1) glyphosate-tolerant soybean adopters used 28% more herbicide than farms that didn’t use glyphosate-tolerant varieties and 2) for corn, adopters of glyphosate-tolerant and insect-resistant varieties decreased herbicide and insecticide use by 1.2% and 11.2%, respectively.

When the environmental impact quotient (EIQ) rather than pounds of product were evaluated, genetically modified adopters and nonadopters used relatively the same amount of herbicides for soybeans and 9.8% less herbicide and 10.4% less insecticide for corn. The EIQ considers a product’s effect on farmworkers, consumers and ecology such as fish, birds and bees.