Drift Checklist

What to Do if You Suspect Dicamba Damage

Emily Unglesbee , DTN Staff Reporter
The distinctive cupping of soybean leaves is a sign of dicamba herbicide injury, so take photographs of any damage you intend to report. (DTN photo by Aaron Hager)

ROCKVILLE, Md. (DTN) -- More than 15 million soybean acres are expected to sport Monsanto's new dicamba-tolerant Xtend trait this year. That's one-sixth of the expected U.S. soybean acreage.

Whether you are growing them or not, do you know where they are?

This awareness will be important for growers of non-Xtend soybeans, which are extremely sensitive to dicamba herbicides.

The new dicamba formulations (BASF's Engenia, Monsanto's XtendiMax and DuPont's FeXapan) are engineered to be less volatile than older dicamba herbicides. Yet, already, reports of dicamba drift damage are beginning to trickle in from states like Missouri and Arkansas.

University of Missouri weed scientist Kevin Bradley has two such cases on his hands -- one in a soybean field and one with homeowner trees. University of Arkansas weed scientist Bob Scott knows of one tank contamination and at least four dicamba drift complaints in his state, some of which are under investigation by the Arkansas State Plant Board.

The good news is that the Engenia formulation, the only dicamba herbicide in use this summer in Arkansas, does appear to be less volatile when used according to the label, Scott said.

The bad news is that mistakes happen, and the spraying season is only now ramping up, he added. Here's a list of steps to take if you see or suspect dicamba injury in your fields or property:

1. MAKE VISUAL CONFIRMATION

Dicamba produces very distinctive injury symptoms on sensitive soybean plants, Bradley said. Seven to 10 days after the injury, newly grown soybean trifoliates will show signs of cupping, as the leaf puckers and the edges curl upwards.

In severe cases, all new growth will display this damage for the rest of the season, but in lighter cases, only a few initial leaves will show it, Bradley said. Leaves present before the drift incident will not appear damaged.

Dicamba injury before the V4 stage usually does not lead to major yield loss, Bob Scott said. But damage that occurs at or after flowering can cause serious yield loss and is harder to spot, Bradley warned.

A close look will show aborted flowers and puckered or aborted pods as well, he said. University Extension agents can help you identify and confirm visual symptoms to soybeans or other plants and figure out your next step.

David Scott, who works in the pesticide division of the Office of Indiana State Chemist, recommends documenting the visual injuries as quickly and comprehensively as you can. Time-stamped photographs of the damaged plants and their location may prove valuable later on if an investigation becomes necessary, he said.

2. MAKE SOME PHONE CALLS

Both Bob Scott and Bradley agree that working out an agreement with the neighbor or applicator responsible for the drift is the best solution.

"I always prefer when neighbors can work things out across the turn row when accidents happen," Bob Scott said. "But when that doesn't work, that's when it's time to call the state agency."

State departments of agriculture or state plant boards are tasked with investigating pesticide complaints.

Like many of the state agencies, Indiana's State Chemist investigators have been specially trained to deal with dicamba drift complaints this year, David Scott said. They are familiar with the many label requirements applicators must follow and dicamba's injury symptoms.

You can also inform the company of the herbicide in question. For complaints regarding Monsanto's XtendiMax herbicide, you can call this hotline: 1-844-RRXTEND. BASF recommends contacting a BASF retailer or representative or using this website to report problems: www.Non-Performance.BASF.US. For FeXapan, the label states that problems should be reported to a local DuPont representative or retailer.

3. GATHER EVIDENCE

If you decide to file a report, there are some things you can do to help a state investigator, David Scott said.

"Our first step is to contact the complainant and then contact the applicator and get information from them," he said. "So any information you can gather beforehand is helpful -- the identity of the applicator, the time of application and any photographs, for example."

The investigators will also gather other evidence such as maps of the area, weather details and plant samples.

Dicamba dissipates from plant tissue in just three weeks, Bradley noted. Smptoms only appear a week after the injury, which leaves growers a narrow window of opportunity for sampling.

You can pull samples and freeze them until investigators arrive, Bob Scott noted. Another option is you can simply send the samples off to a lab yourself, Bradley said.

4. CONSIDER OTHER LEGAL ACTION

Many growers mistakenly believe that a state investigation will result in compensation for any yield losses or damage, David Scott said.

"We don't do yield loss estimates -- we're not insurance adjusters," he said.

The state investigation might produce fines against the applicator, but farmers have to seek compensation for their losses through the insurance coverage of the applicator or civil action. That means contacting the insurance company and likely a lawyer.

"Our findings might be helpful to a grower in a civil case for restitution," David Scott noted. "But that's not our function."

For help identifying dicamba injury, see the Herbicide Injury Database here: https://plants.uaex.edu/….

For more information on yield losses to soybeans from dicamba injury, see this University of Missouri study here: http://bit.ly/….

Emily Unglesbee can be reached at Emily.unglesbee@dtn.com.

Follow Emily Unglesbee on Twitter @Emily_Unglesbee.

(PS/ES/)