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Companies clarify new EPA rules for dicamba

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New label limits use of low-volatility formulations, requires new buffering agents

The dust is still settling from news on Tuesday, Oct. 27, that EPA has approved a five-year registration for dicamba. What does that mean to the companies that make and market these products?

The new rules expand downwind buffers, and lock in application windows for key crops – June 30 for soybeans, July 30 for cotton. In addition, the new formulation dicamba products can now only be used on dicamba-tolerant crops. "Overall the label is simplified," says Tracy Rowlandson, technical market manager for Engenia, BASF.

She explains that for Engenia, and in fact for Xtendimax with Vaprogrip, DuPont FeXapan herbicide and Tavium plus VaporGrip, the rules say these products can no longer be used on conventional crops or for non-crop uses. Dicamba has often been used for weed control in a variety of ways, but for these new formulations, under this new registration, that's no longer possible.

Rowlandson from BASF and Alex Zenteno, dicamba product manager, Bayer, talked with Farm Progress in separate conversations about the new labels and that they mean.

Bringing in a buffer

Perhaps the newest "bullet point" in the EPA rules is the requirement that these formulations be applied with a buffering agent. BASF is rolling out Sentris for this and Bayer will be launching Vaporgrip Xtra Agent.

"What the pH buffering adjuvant does is bring the solution pH up to help reduce the chance for volatility," Rowlandson says about Sentris. "Addition of other products in the tankmix, like glyphosate, can lower the solution pH in the spray tank. When that falls below 5 you convert the anion form of dicamba to the acid form, which increases the risk for potential volatility."

The buffering agent, also called a "volatility reduction agent" will now be required by EPA and applicators must document use and volume used in their records. The buffering agent must also be approved for the specific formulation of dicamba applied. For example, at this time Sentris is the only approved buffering agent for Engenia, both made by BASF.

At Bayer, the answer is Vaporgrip Xtra Agent, which will be added to the tankmix at application. Zenteno explains that this formulation is more than a buffering agent bringing the Vaporgrip technology to the additive. "This is not just a pH buffering agent it's designed to prevent the formation of dicamba acid," she explains.

She offers a short chemistry lesson about the production of protons that can turn to dicamba into an acid. The Vaporgrip Xtra Agent attaches to those protons and prevents the formulation. In fact Vaporgrph technology in XtendiMax is already designed to do that as well. The new additive will be enhancing the presence of Vaporgrip to scrape up those protons and prevent acid formation, which helps reduce volatility.

She adds that Vaporgrip Xtra Agent is not yet approved for use with XtendiMax, but should be in time for application.

What does new label mean?

The new label for these over-the-top dicamba formulations will be simpler clearly stating the cutoff dates, and the downwind buffers. The standard cutoff dates, which could be modified on a state-by-state basis, at least for now avoid the confusion of plant growth stage.

Adds Zenteno: "This is a great label. It is a five-year label which is good not just for companies and EPA but as you think of the grower planting with the Xtend system learning that in 2021 they have five years for planning, that's a big deal."

The added measures in the label also will help reduce the potential for off-target injury and both company representatives note that this strengthens the registration. The label itself is about half the length of the label produced for the 2018 registration and even starts with an application checklist to help the applicator plan for product use.

There are going to be questions about the use of the buffering agent, including what's approved for which products. Farmers may also see state-focused changes to EPA rules, and the agency has noted it is open to discussing local needs.

Farmers can learn more about the new label in depth with this FAQ produced by EPA for the new registration.

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