Herbicide-resistant crops are genetically modified plants that were created to withstand the dispersal of herbicide to kill weeds. Herbicide-resistant crops allow for the use of non-selective or broad spectrum herbicides when managing weeds that endanger crops. Non-selective herbicides are more effective than selective herbicides at killing weeds, leaving fewer of them standing and thereby removing more weeds that threaten crops. They also provide more flexibility to farmers for when they distribute herbicides.
Excessive Herbicide Use
One possible disadvantage of herbicide-resistant crops is that it can potentially lead to farmers using excessive amounts of herbicides in order to attack weeds. Because there is no risk of killing the crops with the herbicides, farmers might not feel the need to be judicious about how they distribute the herbicide. An increased use of herbicides carries environmental risks, possibly leading to increased pollution. Possible effects include contamination of groundwater, carrying risks for human health.
In the case of certain crops, the use of herbicide-resistant crops might trigger the evolution of new species of weeds in the fields, according to the Food and Agriculture Organization of the United Nations. These weeds would be resistant to the herbicides in use and new herbicides would need to be developed and used on affected crops in order to manage the herbicide-tolerant weeds. In addition, volunteer crops resistant to herbicides could emerge as nuisances.
Another potential disadvantage of herbicide-resistant crops is that they are suspected of sometimes harming the biodiversity on the farms where they are used, affecting the ecology of farms in a broader way than is intended. In particular, there are concerns of affecting the diversity of the plant species that are present on farmland where herbicide-resistant crops are planted. However, the risks are low that nearby plant species that are not actually located where the land is cultivated will be affected, according to the Food and Agriculture Organization of the United Nations.
The use of herbicide-resistant crops could potentially affect other crops on the farm that are not herbicide-resistant, leading to a danger of transferring genes to a crop that a farmer wants to keep non-herbicide-resistant, according to the Food and Agriculture Organization of the United Nations. Not only could this potentially occur within a farm but from one farm to an adjacent farm, according to the FAO.