The labels for the three dicamba-containing herbicides registered by EPA for use on Roundup Ready Xtend cotton and soybeans during the 2017 and 2018 use seasons continue to be a work in progress.
New nozzle tips, tank-mixture partners and adjuvants are being added to the websites for the three herbicides – XtendiMax, Engenia and FeXapan – on an almost daily basis, according to Extension weed and agronomy specialists.
Example: XtendiMax with Vapor Grip Technology, which could not be applied with any other products when it was registered by EPA last November, can be tank mixed with 17 other herbicides and 37 adjuvants, as of March 3. It can also be applied with 20 different spray tips vs. the one initially approved.
“This is changing almost daily,” says Darrin Dodds, Extension cotton specialist with Mississippi State University. “If you look at XtendiMax in and of itself, right now there are 17 herbicides listed on that label, and I think there are more probably coming.”
Adjuvants on that label “is a very, very broad classification,” said Dr. Dodds. “It could be a water conditioner; it could be a true adjuvant; it could be a deposition aid – there are a number of them on there.”
Gin Show meeting
Dr. Dodds, and Dr. Larry Steckel, Extension weed scientist with the University of Tennessee, were speakers at the Xtend Your Dicamba Knowledge Seminar at the Mid-South Farm and Gin Show. The seminar was aimed at helping farmers broaden their knowledge surrounding the Roundup Ready Xtend weed control system.
They; Chris Porter, a producer from Matthews, Mo.; Ty Fowler, Monsanto’s technical development manager for cotton traits; and Jessica Christiansen, North American Crops Lead for Monsanto, talked about the latest developments in the long-running saga of the herbicide trait and the three herbicides that have been registered for use with it.
The options for Engenia, the new dicamba formulation developed by BASF, and FeXapan, DuPont’s new dicamba herbicide, were much more limited as of the March 3 meeting. Engenia could be tank mixed with Prowl H2O and Sonic and applied with two nozzles while FeXapan could not be applied with other herbicides and with only one nozzle, the TTI 11004.
The myriad of label requirements “begs the question of why growers shouldn’t just go off label, buy something cheap and go down that road” said Dr. Dodds.
The main reason: “You are violating a federal herbicide label and anytime you do that and, in my case, the Mississippi Department of Agriculture’s Bureau of Plant Industry gets involved.” As a result, it may not end well, according to Dodds.
Can’t ‘un-call’ the BPI
“You cannot un-call the Bureau of Plant Industry, once you call them,” he said. “Somebody’s getting a $5,000 fine out of that. I know they talk about higher fines and lower fines, depending on where you are. But it’s going to happen”
Dr. Dodds said the newly labeled formulations are definite improvements over the older dicamba products. “You look at some of the volatility issues we’ve seen in the past and even some of the tank cleanout issues. Certainly these new formulations are improvements in those areas.”
But there could be other factors involved if growers elect to go off-label with their dicamba formulations. That’s because some of those may be packaged in the same plants where products containing 2,4-D are being formulated.
Dr. Dodds talked about receiving a call from a grower who admitted spraying a dicamba formulation on his cotton last year and wanted to know how much the injury symptoms could affect his yields.
“I asked him to send me some photos and a sample of the product,” said Dodds. “I have two things circled on the report that came back on the sample. One is 2,4-D and the other is 19 parts per million. He had 2,4-D in his dicamba formulation.
Jump on the cotton
“You think about 19 parts per million, and it’s not very much. But I can tell you 19 parts per million was enough to jump on the cotton in this situation pretty hard. The cotton just sat there and looked bad.”
If the formulation is not intended for in-crop use, he said, the tolerance levels for 2,4-D can be relatively high, some as much as 1,000 parts per million. “If you spray an off-label dicamba product on your cotton with 1,000 parts per million 2,4-D, I can tell you you’re not going to pick that cotton.”
Dr. Steckel said farmers in west Tennessee could plant as much as70 percent of their cotton in Roundup Ready Xtend varieties with “30 percent in something else, mostly Enlist or Liberty Link cotton.”
From 45 to 50 percent of the soybeans are expected to be planted in Xtend varieties, he noted.
“Why did we see this big sea change; why did we have to move to these new technologies,” Dr. Steckel asked. “The fact is we’re running out of herbicides on Palmer amaranth in particular, but other weeds, as well.”
That makes it even more important to steward those old/new herbicides through increased diversity of choices and use of non-herbicidal controls, says Dr. Steckel.
For more information, see http://www.deltafarmpress.com/soybeans/epa-issues-highly-restricted-label-new-dicamba-formulation.
To watch more videos from the Xtend Your Dicamba Knowledge Seminar at the Mid-South Farm and Gin Show, click on: