All year in the Midwest and Southeast, the biggest story in agricultural circles has been problems triggered by the widespread planting of dicamba-resistant soybeans and cotton. At issue – damage to non-target plants and trees. This herbicide is highly prone to movement from treated fields onto surrounding cropland, trees, and other vegetation.

Some 20 million acres of dicamba-resistant (DR) soybeans were planted in 2017 (about one in every four soybean acres nationwide), and another 5 million acres were planted to DR cotton (about one-half national acreage). As a result, at least 4 million acres of non-DR crops, trees, and vines have been damaged in 2017 by drift and off-target movement of dicamba.

So, in crop year 2017, close to one acre of non-DR plants or trees was damaged for every four acres planted to DR crops.

On September 21th, the New York Times recounted the scope of dicamba-driven problems in 2017. The story reports the difficult time farmers, regulators, and the pesticide-biotech industry are having in figuring out what to do in crop season 2018. Danny Hakim’s penetrating NYT piece is entitled “Monsanto’s Weed Killer, Dicamba, Divides Farmers”.

In crop year 2018, close to 60 million acres will be planted to DR crops, and the damage to nearby crops, vines, and trees will almost inevitably be much worse. But people are at risk too, a dimension of the dicamba story that is just touched upon in the NYT piece.

Our Dicamba Watch presentation was recently featured in the New York Times, access it and other Herbicide Timelines here.

The online version of the Hakim piece contains a link to our “Dicamba Watch,” which the Times accessed from this website. Those interested in the history, regulation, and trajectory of use of dicamba can also view Parts I, II, and III of what we call the “Dicamba Diary.”

One goal for this project is to help the biomedical community, and others concerned about the possible impacts of rising herbicide use on reproductive outcomes and birth defects, understand the history and current regulatory conditions of use governing the three herbicides most directly associated with the rapid expansion in herbicide use in the Midwest — glyphosate, dicamba, and 2,4-D.

Concern is rising in the public health community, and especially among obstetricians and pediatricians working with patients living in rural areas, and for good reason. Across the Heartland and throughout the Southeast, the levels of exposure to dicamba and other herbicides, the frequency of exposures, and duration of exposures rose markedly in 2017, and will take off in 2018-2019.

Our project’s primary goal is determining whether these changes in human exposures lead to adverse human health outcomes, and what can be done to prevent such outcomes.

We approach our work with a rising sense of urgency for three reasons. While limited in scope, biomonitoring data show that the levels of some herbicides in people, including pregnant women and infants, are becoming more common and are rising.

Second, preliminary studies report a possible connection between higher levels of exposure to herbicides and some common birth defects and reproductive problems, like spontaneous abortions.

And third, the primary strategy promoted by the pesticide and seed industry to resolve the crop-damage problems triggered by dicamba drift is to genetically engineer all the soybeans, corn, and cotton grown in the Midwest and Southeast to be resistant to dicamba. This more-of-the-same strategy could lead, down the road, to soybeans, cotton, and corn engineered to tolerate four, five, or even more herbicides, so any farmer can spray any registered herbicide, and not put a neighboring farmer growing the same crop, or another DR crop, at risk.

Among the obvious concerns exacerbated by this strategy are even more rapidly rising use of dicamba and other herbicides, and an unprecedented threat to fruit and vegetable plants, trees, and other vegetation that will not be resistant to any of these herbicides.

We will continue to track developments with herbicide-resistant crop technology and herbicide use and risks, in the hope a safer and sustainable way can be found to manage weeds in these parts of the country.


Danny Hakim, “Monsanto’s Weed Killer, Dicamba, Divides Farmers,”   New York Times, September 21, 2017.

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