Did Rains Negate Dicamba Damage to Soybeans?

Russell “Wally” Huschka, who farms in Barnes and Steele counties in North Dakota, saw the “cupping” of soybean leaves just prior to July 4. Two fields were hit with off-target dicamba herbicide, for a total of about 50 to 60 acres.

Three months later, the results are trickling in.

One of Huschka’s locations came in at 37 bushels per acre, a bushel or two more than the unaffected rest of the field. Another field was 40 bushels per acre, about equal to the rest of the field.

But it wasn’t entirely a surprise.


Huschka has a prior history with dicamba. In 2008 or 2009 he’d sprayed some “Status” — a BASF dicamba formulation for broadleaf weed control on conventional corn. Some of it affected some of his own soybeans. Back then, the crop received some rain and the soybeans “grew through it” and he couldn’t ultimately see a difference in yield from where the crop had been affected versus where it wasn’t.

This year, with new formulations on the market, Huschka saw his damage but didn’t know what to expect. He reported the apparent effect to the attention to the neighbor who’d sprayed.

“We said we’d watch it for the summer and see how it comes out,” Huschka says.

But the neighbor also instantly took it to his liability insurance agent. The insurance company “came right out and give us our option — that day — to take that day’s price at five bushels an acre, or leave the acres.” Huschka was willing to drop off 10 acres and settled for 50 acres at that price — essentially about $45 per affected acre, or about $2,250.

By the middle of the next week, “all of the insurance companies said they weren’t paying a thing on it,” Huschka says. He speculates that insurance companies thought spray records would indicate that their clients had sprayed according to labels, that it was a manufacturer error.

Bad to good

The damage initially looked “terrible” on the drier nobs, Huschka says, but the severity was uneven. It was dry in July and things “stood still for awhile.” But the rains came in August, and the beans seemed to be flowering and putting on pods as they should.

Huschka laughs and says he can’t explain a yield increase of any kind after being affected by herbicides.

“You hear about these ‘gurus’ going out and hitting their beans,” he says. “The timing must’ve been right that it worked out that way.”

He declines to speculate on whether the fields would have been fine if it hadn’t rained.

“It might have been fine. The rest of the fields might have been 20 bushels less (per acre), too, if we hadn’t gotten that rain,” he says.


Rich Zollinger, North Dakota State University Extension Service weed specialist, says some county agents have reported that farmers are feeling their yields have been affected very little by the dicamba.

“If that were true across the whole state, it would be wonderful,” Zolllinger says.

Soybeans can recover quickly and effectively from an injury or stress. “They’re kind of elastic in their growth,” he says.

If growers supply information for a University of Missouri-led survey for this year’s crop, that will be a good start for understanding what to do for subsequent years. The survey asks for a half dozen environmental influences such as humidity and air speed, with public weather systems such as NDAWN (North Dakota Agricultural Weather Network).

Zollinger says the dicamba drift has caused injury on soybeans across the whole United States in 2017. One of the important things regulators don’t yet know is the effect on yield. Some research shows drift early in the soybean plant’s life cycle is not as damaging as drift happens “closer to flowering and reproductive states.

The drift “in the air” has different concentrations, he says. “Even though it might cup the beans, we don’t know exactly to what extent that drift will yield in yield reduction,” Zollinger says.

It’s about yield

When beans received “life-saving rains” during their reproductive phases, “farmers make money by yield, and if yield is impacted, that’s certainly going to hurt everybody,” Zollinger says, adding that he thinks “regulation is independent of yield loss. Farmers and others saw, with their human eyes, injuries, and that’s enough to begin extra regulation to see if we can stem what happened this year.”

The Environmental Protection Agency added about a dozen points of restrictions to the label — specifying wind speed, speed of applicator travel and other things to monitor and reduce the risk of drift. He says state regulators may add additional items, from academia and farmers.

Huschka says he isn’t sure whether regulators should make regulations tighter, but acknowledges he doesn’t want to see leaf-cupping again.

“I know my own weed situation,” he says. “I need a chemical that’s going to take care of your waterhemp, common ragweed, and others. We need something in soybeans that’s going to knock them flat. I’m leaning toward dicamba. I would prefer to keep using some.”

Huschka had 450 acres of dicamba beans of his own this year, where there were “no issues” with them.

“We need something, but we’ve got to learn to control the volatility issue, As smart as we are this day and age somebody should figure this out,” he says.

Source: Mikkel Pates, Agweek

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