Dicamba: Top Stories and Takeaway Facts

What is dicamba?

Dicamba is a selective herbicide in the benzoic acid family of chemicals. It is registered for agricultural use 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.

How is dicamba used for agriculture?

The widespread adoption of Monsanto’s first generation of Roundup Ready crops – engineered to tolerate glyphosate, aka Roundup – has worsened weed problems on farms and created herbicide-resistant superweeds. To combat these weeds, Monsanto engineered new soybean and cottonseeds to withstand a chemical cocktail of glyphosate and dicamba.

In 2016, the Environmental Protection Agency registered new dicamba formulations approved for “over-the-top” use, or use on growing plants, to control weeds on cotton and soybean plants that are genetically engineered to resist the herbicide.

Only dicamba products registered for use on genetically engineered cotton and soybeans can be applied over the top. It is a violation of the Federal Insecticide, Fungicide, and Rodenticide Act to use any other dicamba product that is not registered for use on genetically engineered crops over the top.

Dicamba drift damage

As of November 2017, dicamba has damaged more than 3.6 million acres of soybean crops or about 4 percent of all soybeans planted in the United States. The EPA is calling for an urgent federal response.

Dicamba drift damages unprotected, nonresistant crops by stunting their growth and marking the plants with withered leaves. These crops are then unable to produce a yield and, in most cases, the farmers affected have to report the damaged crops as a total loss.

Dicamba is not particularly new, but dicamba-resistant soybean seeds are, as are newer versions of dicamba that Monsanto and BASF – the companies behind the pesticide – claim are designed for the seeds. But dicamba has shown a tendency to vaporize rapidly and drift onto neighboring farms. If neighbors have not used dicamba-resistant seed, the drift is incredibly destructive. Monsanto has laid the blame for dicamba drift damage at the feet of farmers, claiming that they have not been following directions for proper use. Meanwhile, farmers using dicamba-resistant seeds said the directions from Monsanto are nearly impossible to follow.

Most of the drift damage complaints were related to soybeans, but the drift has also harmed other crops, including tomatoes, watermelon, cantaloupe, vineyards, pumpkins, organic vegetables, residential gardens, trees and shrubs, researchers found.

Last year the EPA reached an agreement with manufacturers on measures to minimize the potential for dicamba drift to damage neighboring crops. The registrants voluntarily agreed to registration and labeling changes, including restricting the use of these products restricted-use, setting recordkeeping requirements, and implementing certain additional spray drift mitigation measures. New requirements for the over-the-top use of dicamba “over the top” (application to growing plants) will allow farmers to make informed choices for seed purchases for the 2018 growing season.

In an effort to limit the damage, the EPA announced that new instructions about how to apply the herbicide would be sent to farmers nationwide for use next year.

Illegal use and criminal complaints

As stated in Reuters, in 2015, Monsanto had bred the dicamba-resistant trait into its entire stock of soybeans, the only alternative would have been “to not sell a single soybean in the United States” that year, Monsanto Vice President of Global Strategy Scott Partridge told Reuters in an interview.

Betting on a quick approval, Monsanto sold the seeds, and farmers planted a million acres of the genetically modified soybeans in 2016. But the EPA’s deliberations on the weed-killer dragged on for another 11 months because of concerns about dicamba’s historical drift problems.

In 2016, Monsanto started illegally selling a new dicamba-resistant seed, called XtendiMax, without EPA approval. Then farmers began using the seeds without the proper chemicals to go with the crop.

There has been an avalanche of criminal complaints regarding dicamba, and many reports of affected farmland. The State Plant Board is quoted stating, “the $1,000 fine doesn’t seem to be deterring anyone.” But, fines and crop damage are not the worst stories surrounding the dicamba issue. In one case another farmer murdered a farmer over illegal use and crop damage. In another case, Missouri’s largest peach farmer is suing Monsanto for putting out Dicamba-tolerant seeds without the new spray to go with it. Monsanto says the suit is baseless; that it’s not their fault people sprayed a chemical they weren’t supposed to.

Maps from a Modern Farmer investigation, using data from various state departments of agriculture and weed scientists, summarizes all of the damage from the illegal and improper use of these Monsanto products.

These maps show 2,708 dicamba-related cases in progress, ranging from North Dakota to Louisiana, and as far east as North Carolina. The state with the single highest number of cases in Arkansas, with 986.

Arkansas was one of the states that issued a temporary ban on the sale and use of dicamba this summer.

The map of affected acreage is even scarier, ranging to the east coast as far north as Pennsylvania and as far south as Georgia. Arkansas again was hit the hardest, but the Dakotas and Minnesota were severely damaged as well. Altogether, Bradley’s map shows 3.6 million acres of soybean fields damaged by dicamba.

Whether the recent decision to make dicamba a restricted-use pesticide will result in less damage is unclear, especially as big chunks of the affected areas enter winter.

In response to mounting evidence, widespread complaints, and local bans, the Environmental Protection Agency, at the suggestion of Monsanto, has taken steps to restrict the pesticide dicamba.

In an attempt to curb the complaints, Monsanto has offered cash to U.S. farmers who use the controversial chemical. The incentive to use XtendiMax with VaporGrip, a herbicide based on dicamba, could refund farmers over half the sticker price of the product in 2018 if they spray it on soybeans Monsanto engineered to resist the weed killer, according to company data.

States banning dicamba use

EPA documents show 2,708 complaints had been reported to state agriculture officials about dicamba crop damage as of mid-October. They came from 25 of the 34 states where the “over the top” application is approved for use. The largest number of complaints was filed in Arkansas, where there were 986 incidents, and Missouri, which had 310.

The EPA documents suggested the number of complaints understated the problem because most incidents went unreported. He estimated the actual number of damage incidents could be five times greater than the Missouri researchers found.

Several state officials asked EPA officials at the Wednesday meeting how the agency would evaluate the extent of the dicamba drift problem at the end of 2018 growing season, and determine whether the corrective measures had gone far enough. Arkansas state officials have already moved toward banning the use of dicamba because of the crop damage in their state this year, though the pesticide companies are challenging that effort.

There is a new, approved Dicamba on the market that’s not supposed to drift so much. But there are already reports of damage to crops, whether from legal or illegal use. And as NPR describes, weed scientists have a longer-term worry that once everyone starts using Dicamba like they used Roundup, the pigweed will play that trick of Mother Nature and become resistant again.