Unintended Effects of the Intended Herbicides on Transgenic Herbicide-Resistant Crops

The herbicides used with crops that have been made resistant to them with transgenes are assumed to have no significant effects on these crops. Crops made resistant to glyphosate, glufosinate, dicamba, 2,4-D, mesotrione, and isoxaflutole are discussed in this paper. Most of the literature on this topic has been on glyphosate-resistant crops, as these have been the most successful of all herbicide-resistant crops. Reports of adverse effects, such as phytotoxicity symptoms, disrupted mineral nutrition, and reduced yield, caused by these herbicides on these crops are reviewed and critiqued herein. These reports are often conflicting, however, and there is no consistent evidence of any major adverse effects of these herbicides on these crops. Literature on the accumulation of residues of the intended herbicides in the parts of the plants that are used as food is also discussed. Reports of potential unintended beneficial effects, such as effects on crop pests and stimulation of crop growth and development are also critiqued.