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Dicamba takes its final curtain call

By Staff | Jul 1, 2020



The last few weeks, many farmers have seen a product they were going to rely heavily on for weed control stripped from them only to have it given back a few days later with heavy restrictions.

Earlier this month, the U.S. EPA issued a cancellation order for three dicamba-based herbicides: Xtendimax with Vaporgrip Technology, Engenia and FeXapan.

According to information provided by Iowa State University Extension, the order followed the Ninth Circuit’s immediate vacatur of the EPA’s conditional registrations for these herbicides on June 3. In the case, the court found that the EPA violated the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) by substantially understanding some risks of dicamba and by entirely failing to acknowledge other risks. The court ruled that there was no substantial evidence to support the EPA’s decision to register the herbicides.

This court order led to widespread concern, in particular, regarding whether farmers or applicators with existing stocks could use the product already on hand.

“It couldn’t have come at a worse time because beans were ready to start being sprayed, and then so all of a sudden the tool that more than half of Iowa’s farmers were planning to use was no longer available,” said Bob Hartzler, Iowa State University Extension weed specialist.

Iowa Secretary of Agriculture, Mike Naig also shared his disappointment with the Ninth Circuit Court’s decision to overturn the EPA’s approval of products.

“The Court’s decision has left farmers without a critical weed management tool at the same time they are treating growing crops. I’m grateful that EPA recognized the hardship this places on our farmers and issued an order allowing them to use existing stocks to finish out the 2020 growing season,” he said.

The cancellation order regulates the distribution and use of “existing stocks” legally purchased pursuant to EPA-issued registrations. Generally allowing the stocks to be used through July 31, 2020.

According to the EPA the order addresses the sale, distribution and use of existing stocks of XtendiMax with Vaporgrip Technology, Engina and FeXapan.

  • Distribution or sale by any person is generally prohibited except for ensuring proper disposal or return to the registrant.
  • Growers and commercial applicators may use existing stocks that were in their possession on June 3, 2020, the effective date of the Court decision. Such use must be consistent wit the product’s previously-approved label, and may not continue after July 31, 2020.

“Basically they are saying all stocks have to be used by July 31,” said Hartzler adding here in Iowa the majority of the soybeans approved for a post emergence application of dicamba would be off label due to the fact they have been in the ground for more than 45 days.

What does this mean for the future of dicamba?

“When you look at EPA’s ruling, it sounds final,” said Hartzler. “They said these products are not coming back. And, so that would mean that dicamba for post emergence use on soybeans in 2021 is not a viable option.”

Allowing producers to follow through with their post emergence dicamba herbicide application plans for the year, Hartzler said gives those that depend on those Xtend Genetics and herbicide to find alternatives for next year.

“In my opinion, we can move on,” he said. “We have a variety of options, and we have the time to evaluate and determine what is best for a specific operation. Whereas with the decision that was made last week, farmers didn’t have plans and they didn’t have flexibility because the beans were already in the ground. That was what was so bad about the decision.”

The biggest tool in weed control, Hartzler said is pre emergence products; however, they can’t handle an entire season of weed control all on their own.

“We still have to continue to rely on pre emergence products,” he said. “None of our pre emergence products are strong enough to get the job done on their own, so that is why we need effective post emergence products.”

With conventional soybean varieties, Hartzler said one option would be PPO Inhibitor herbicides.

“Those are effective, but over half of our fields have waterhemp that is resistant,” he said. “That is why growers are interested in a trait to provide them additional options.”

Hartzler said he agrees with the decision to eliminate the usage of dicamba in post emergence applications in soybeans.

“I believe the particular use should go away,” he said. “I think we have sufficient evidence showing that current formulations have issues with volatility. A farmer could do everything right and still run into problems because of volatilization.”

The EPA previously tried to control the volatility issue, putting additional restrictions on the label, but to no avail.

“The EPA tried to add restrictions to the label to reduce the probability and what that did was put growers in a really difficult spot because it was almost impossible to find suitable hours to apply the product where environmental conditions were within the label guidelines,” he said. “That just placed applicators in a really, really difficult position.”

Plants that occur throughout the landscape in the mid-south, he said were being damaged significantly by post emergence applications of dicamba.

“Trees can take getting hit by herbicides every so often, but if you keep doing it every year, the added stress just builds up and is not good for their long term survival,” he said.

Although Iowa hadn’t received the wide scale off-target movement injury as those areas in the mid-south, there had been enough damage, Hartzler feels.

“What I have seen in Iowa, I haven’t seen trees or plants in the landscape that I thought their long term health was being jeopardized. I just felt there was too much injury going on and some farmers are even defensive planting Xtend soybeans in order to prevent their beans from being damaged by their neighbors,” he said.

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