Monsanto's Dicamba Resistant Seeds

In 2015 the U.S. Department of Agriculture (USDA) allowed the sale of seeds that have been genetically engineered to tolerate dicamba, a selective herbicide. Monsanto introduced a new product called Xtend a genetically modified soybean seed that is resistant to the herbicide. Dicamba is already registered (approved by the EPA) for uses in agriculture, on corn, wheat and other crops. Dicamba is also registered for non-agricultural uses in residential areas, and other sites such as golf courses, mainly to control broadleaf weeds such as dandelions, chickweed, clover and ground ivy.

One of the main concerns about genetically engineered crops such as Roundup Ready crops and now the new genetically modified soybean and cotton seeds that are resistant to dicamba and 2,4 D is the development of weeds and other plants that are also resistant to the pesticides. Glyphosate (N-phosphonomethylglycine), the active ingredient in the herbicide Roundup is also manufactured by Monsanto and is the most popular herbicide in use today in the United States, and throughout the World. Americans spray an estimated 180-185 million pounds of the weed killer, on their yards and farms every year.

The massive adoption of genetically engineered resistant crops in soybean-, maize and cotton-growing regions of the United States has resulted in evolution of glyphosate-resistant weeds. The first reported resistant weed was in 2001, Conyza canadensis L. This occurred after more than 25 years of glyphosate use. However, the development of resistant species of weeds has speeded up. There are now several known glyphosate-resistant populations of the very vigorous, highly competitive and economically damaging ragweeds Ambrosia artemissifolia L. and Ambrosia trifida L.

Researching this scientists found that If there is a sufficiently diverse system of weed management, herbicide resistance may evolve only very slowly or not at all. However, the reality is that most farmers using Roundup resistant seeds rely on glyphosate alone, with markedly reduced diversity in other weed management tools historically used like burndown, glyphosate use before crop seeding, or physical tillage were found to minimize glyphosate-resistant weeds, but they increased runoff of pesticides and soil. These methods were abandoned to the easier and no till method of spraying once the crop emerges. The result is that Roundup is not working so well anymore. So, Monsanto has come out with their new product With the new dicamba and 2,4 D resistant seeds.

The New York Times reports that the expanded use of dicamba is damaging nearby traditional crops through vaporization and  pesticide that is carried on the wind. That is the first problem to be seen. The development of weeds and other plants that are also resistant to the pesticides will happen. Right now dicamba kills weeds that can no longer be controlled by Roundup. In the long run it is likely that weed resistance to dicamba will increase. There are more sustainable methods of weed control.