GM crops lead to rise in pesticides
Genetically modified crops have increased agriculture’s dependence on pesticides, according to a study published in the Journal of Agrarian Change in April 2025.
Drawing on data from four GM crops—a case study of insecticide-producing cotton in India and a global analysis of herbicide-tolerant soy, maize and canola—the researchers traced the increase in GM crop production over three decades alongside a surge in chemical use.
GM insecticide-producing cotton was introduced in India with the promise of reducing chemical pesticide use and, by the mid-2000s, GM cotton covered most cotton-growing areas. The researchers found that pests developed resistance and farmers responded by spraying more insecticides. By 2018, they were spending 37% more on insecticides than before the introduction of GM cotton.
In the US, crops genetically modified to survive being sprayed with the weedkiller glyphosate initially made weed management more efficient. The result was a dramatic escalation in glyphosate application. Between 1994 and 2018, the percentage of area treated with glyphosate rose from 15% to 87%.
But contrary to the predictions of its manufacturer Monsanto (now Bayer), weeds developed resistance. GM crops have since been created to be resistant to even more dangerous chemicals.
Likewise, in Argentina, Brazil and Canada, GM crops promised simpler weed control but delivered higher herbicide use.
The study is a timely reminder of the false promises that accompany GM crops. As she introduced the UK’s new regulations for new GMOs in March 2025, Emma Hardy MP said that they would be resistant to pests and diseases and reduce the need for pesticides. The study highlights the lack of evidence to support such claims.
The authors recommend pursuing systemic change rather than “incremental technical fixes toward efficiency”. They state: “In complex living systems like farms… the long game of stability through diversity makes for a better evolutionary strategy.”
