The EPA has announced it will extend the registration of dicamba for two years for over-the-top use in dicamba-resistant crops.
Jason Norsworthy, University of Arkansas weed scientist, was unfazed by the news. “There’s nothing there that surprised me. I’ve been in correspondence with the agency over the past few months, and I know they have been poring over a wealth of data. I do think what they have put out takes things a step further than where we were at in 2017 and 2018.
“I just want to caution everyone: what we’ve seen so far are talking points or modifications that will occur to the label, not the label itself.”
Will what the agency is proposing be sufficient in addressing all the issues seen in grower fields?
“No. But, again, what needs to be pointed out is none of us has actually seen the label. My understanding is there isn’t a physical label out, at least not publically at this point. It is difficult to comment on the new label until I can physically see it.”
How might the new EPA label line up with the Arkansas State Plant Board regulations?
“I have no idea what the Arkansas Plant Board will do. It would be pure speculation. All I know is they next meet on Nov. 5. I do know the federal label hasn’t greatly impacted how the state has managed dicamba.”
The new EPA dicamba registration decisions include:
- Only certified applicators may apply dicamba over the top (those working under the supervision of a certified applicator may no longer make applications).
“The question I have on that is: are they referencing all certified applicators? Certified commercial applicators? Certified private applicators? I don’t think we’ll be able to answer that until there’s a physical label in front of you.”
- Prohibit over-the-top application of dicamba on soybeans 45 days after planting and cotton 60 days after planting.
“I don’t see that being a lot different than where we are now. In soybeans, there’s a reproductive restriction due to residue tolerance. Additionally, weed control in soybeans is generally completed by 45 days after planting. I don’t know of many folks spraying soybean eight to nine weeks after planting.
“In cotton, we don’t typically spray the crop over-the-top beyond 60 days after planting. Depending on where you are in Arkansas, we try to plant cotton mid-April to early May and we are spraying layby no later than July 1 in most years.”
- For cotton, limit the number of over-the-top applications from four applications to two applications (soybeans remain at two over-the-top applications).
“Originally, the label allowed four over-the-top applications. There was no real opportunity to spray cotton four times over-the-top. Taking it back to two is typically where most growers would be. Also, growers have glufosinate (Liberty/Interline) that can be used for pigweed control in XtendFlex cotton.”
- Applications will be allowed only from one hour after sunrise to two hours before sunset.
“I fail to see how this will have a significant impact on off-target movement. I assume the agency is trying to prevent spraying into an inversion. I think Missouri and Tennessee tried this in 2017 and it had no impact on the issues they dealt with.”
- In counties where endangered species may exist, the downwind buffer will remain at 110 feet and there will be a new 57-foot buffer around the other sides of the field (the 110-foot downwind buffer applies to all applications, not just in counties where endangered species may exist).
“What that tells me is the agency is saying because of volatility the product moves in multiple directions. They’re trying to take an additional measure to protect endangered species. Prior to this, there was only a downwind buffer.”
- Clarify training period for 2019 and beyond, ensuring consistency across all three products.
- Enhanced tank clean-out instructions for the entire system.
“These are the same comments that were made at the end of 2017 and going into 2018. It seems like these are some of the same bullets from previous years.”
- Enhanced label to improve applicator awareness on the impact of low pH’s on the potential volatility of dicamba.
“That gets into some research I and colleagues elsewhere have conducted. We’ve found that when you add glyphosate to the spray tank and the pH is lowered, it increases the volatility of the spray mixture. I don’t see them pulling glyphosate off the label even though we know it increases the volatility of the dicamba products.”
- Label clean up and consistency to improve compliance and enforceability.