Dicamba Debate Continues

States Contemplate More Herbicide Restrictions

This soybean field in Illinois is showing symptoms of off-target movement of a new formulation of dicamba that was sprayed in a neighboring field. (DTN photo by Pamela Smith)

DECATUR, Ill. (DTN) -- States continue to debate regulations on dicamba herbicide that is the suspected cause of widespread crop injury across several states.

The Missouri Department of Agriculture said it may lift the temporary ban on the sale and use of in-crop use of the herbicide this week if a new label is developed that institutes additional safeguards. The state has received over 130 official complaints related to dicamba since June 13, 2017.

Both Monsanto and BASF, companies that manufacture dicamba herbicides designed to work with new Xtend-traited soybeans and cotton, confirmed to DTN that they have been actively working with state rule makers. "We are hopeful we will be able to reach resolution on this matter in very short order," said Monsanto spokesman Kyel Richard.

In a formal statement, BASF said: "The Missouri Department of Agriculture is requiring a Special Local Need Label for Engenia herbicide (and all other low-volatility dicamba formulations intended for use on dicamba-tolerant soybeans and cotton) for the remainder of the 2017 growing season. Because we believe it is important for growers to be able to continue to access Engenia herbicide at this critical point in the 2017 season, we have already proposed the text of such a label to Missouri, according to their direction." Neither company would confirm any details behind the discussions, claiming they were "confidential."

The Tennessee Department of Agriculture (TDA) also confirmed that it is also working closely with producers, industry representatives, manufacturers and the University of Tennessee to address complaints of potential off-target movement of dicamba. As of July 11, state officials told DTN they were investigating 69 complaints of possible dicamba drift and were considering additional regulatory measures.

In Arkansas, official complaints continue to pile up with 633 recorded as of July 11. An official ban of dicamba sales and spraying in row crops began at 12:01 a.m. on July 11.

With cupping and puckering symptoms characteristic of dicamba deposition taking as much as three weeks to show in new growth on soybeans, reports from the Midwest have been slower to materialize. However, Iowa State University weed specialist Bob Hartzler reported on the situation in his state here: http://crops.extension.iastate.edu/….

University of Tennessee weed scientist Larry Steckel predicted spraying will finish up in the next 10 days in his state. He said most of the sensitive soybeans are showing some level of injury.

"We've probably got the highest concentration of dicamba-tolerant crops on the planet -- roughly 60% of the soybeans are Xtend and about 80% of the cotton," Steckel said. "Concentration of crops and the fact that some of these guys are on their third year of having injury is a large reason you're hearing more from Southern states so far," he said.

The label associated with the approved low-volatility dicamba formulations called XtendiMax, FeXapan and Engenia are already complicated without further restrictions. "Following them as they are now is a Herculean task. Talk about threading the needle -- you can't spray when it's too windy. You can't spray under 3 miles per hour. You got to keep the boom down -- there are so many things," Steckel said. "It looks good on paper, but when a farmer or applicator is trying to actually execute that over thousands of acres covering several counties, it's almost impossible."

Steckel, like weed specialists in other states, say much of the injury they are seeing this year seems related to the herbicide moving as a gas at some point after application. "This is landscape level redistribution of that herbicide," Steckel said, compared to physical drift that often injures in a pattern in the field.

"It's 200-acre or larger fields covered pretty uniformly. I've never seen anything like it," he said.

Fields that got hit early with light doses of herbicide may not have yield losses. "However, these fields that got hit multiple times are struggling. Some of them aren't boot-top tall and they were planted May 1. They are likely going to have some significant yield loss."

Steckel said the good growing conditions his state is currently seeing may help beans recover. However, he recalled that fields hit multiple times last year saw up to 40% losses in yield.

In 2016, many of the yield losses were worked out neighbor-to-neighbor, he said. "This year it is whole crops and not just a field or two," he said. "And there's often no way to know which neighbor it was since we're seeing lots of movement [of the herbicide]."

He added that many farmers abandoned dicamba sprays and turned to other herbicide options to avoid hurting neighboring crops further. Depending on the weed control pressure and problems, that's a sacrifice and potential loss of income for those that bought into the technology, he agreed. "Mostly farmers want to do the right thing."

"I'm just not sure we can steward this technology as it currently exists," he added.

"This is bigger than soybeans too. I've seen dicamba injury in vineyards, commercial tomatoes, peas and trees this year. Homeowners are really starting to catch on to this, and I'm afraid agriculture is going to start to lose public support in other areas because of it," he said.

Dicamba resource pages and updates available here:

Arkansas: http://www.aad.arkansas.gov/…

Iowa: http://www.iowaagriculture.gov/…

Kansas: https://webapp.agron.ksu.edu/…

Missouri: http://agriculture.mo.gov/…

Tennessee: https://www.tn.gov/…

Pamela Smith can be reached at Pamela.smith@dtn.com

Follow her on Twitter @PamSmithDTN