Tractor Spraying Herbicide on Field

To understand the environmental effects of GMOs, I started by looking at plants genetically modified to be insect-resistant — and concluded that they have, on balance, helped reduce overall insecticide use in U.S. farming. The picture isn’t so rosy with the other main trait that GM agribusiness promotes, herbicide tolerance.

While it’s clear that genetic engineering has reduced the amount of insecticides that farmers spray, it’s just as clear that it has encouraged a much larger increase in the use of the herbicide glyphosate. And while insect resistance is safeguarded by some (insufficient) regulations, there are no regulations to rein in the way that herbicide-tolerant plants encourage overuse of herbicides.