A fair number of producers appear to be trying the new dicamba-tolerant cotton varieties this spring. They will not be allowed to spray dicamba over the top of them because it’s not labeled for that use in cotton.
But weed scientists like Larry Steckel, Extension specialist with the University of Tennessee, says it’s not too early for growers to be thinking about how they will apply dicamba – they can spray glyphosate and glufosinate over XtendFlex cotton now – including what nozzles they will use when the products are labeled for 2016.
“Xtend is here,” says Dr. Steckel. “It’s become very apparent as I’ve gone through the whole meeting circuit with our growers, but I’d be willing to bet that 50 percent of our cotton will be Roundup Xtend cotton in 2015.”
Speaking at Adama’s Southern Crop Consultants meeting in Memphis, Tenn., Dr. Steckel said growers originally thought they would be able to spray dicamba on the cotton in 2015. EPA, however, did not approve a label for the new dicamba formulations from Monsanto and BASF, and growers cannot apply it in cotton in 2015.
“We’re still going to be able to use Roundup, and we’re still going to be able to use Liberty,” he noted. “I’ve really been pushing stewardship because it will be huge going forward. If any of you have been in meetings with Monsanto, you know they’re stressing it, too.”
Based on the label that’s been issued for Dow AgroScience’s new Enlist technology and preliminary information from Monsanto and BASF, the new regulations will represent a paradigm shift for U.S. agriculture.
“Never before have we had a label for any pesticide that specified exactly what nozzle you had to have to apply it,” Dr. Steckel said. “And some of these nozzles like these TTIs that they favor are not going to be so sporty with the fungicides and insecticides we’re applying.
“Exactly what the Roundup Xtend label will look like we don’t know,” says Steckel. “At one time they were just going to go with the TTIs or Turbo Teejet Inducation nozzles because they provide large droplets. Since then, they’ve added more nozzles such as the AIXRs or Teejet Air Induction nozzles, which seem to be as close to a happy medium as we’re going to get.”
EPA has issued a label for the Enlist weed control system, which may give growers an idea of what to expect for Xtend Flex. “I can’t imagine EPA will approve a label that is that much different.”
With the XtendFlex varieties growers will be able to apply glyphosate from pre-emergence to harvest and glufosinate from pre-emergence to mid-bloom. The proposed dicamba label would also cover from pre-emergence to harvest.
Enlist corn can be sprayed with Enlist Duo, its new formulation of 2,4-D, up to V8 or 30 inches; Enlist soybeans and Enlist E3 soybeans up to R2 or full flower; and Enlist cotton up to mid-bloom.
“Some are asking why are we putting 2,4-D tolerance in corn – can’t we use it up to 30 inches anyway?” says Dr. Steckel. “You can. The other thing it gives us is fop resistance. You can put Assure II herbicide on the corn.”
Steckel displayed the nozzle requirements on the Enlist label, saying growers have never seen the types of nozzles that must be used spelled out in such a manner before. “Look at this. We have an 03, an 04 and an 06 nozzle on the Greenleaf nozzles. What happened to the 05? I can tell you they probably haven’t done the wind tunnel tests on the 05 yet.”
Another potential problem area that may come into play are pulse modulating spray systems. Dr. Steckel says most of the pulse modulating systems will not work with the venturi-type nozzles, such as the TTI or an AIXR nozzle that will be on the label for the new herbicide formulations. The exception is the Wilger nozzle.
Some growers think the new dicamba and 2,4-D traits will allow them to go back to early Roundup Ready days when they could kill 12- to 15-inch Palmer amaranth with an application of glyphosate. That will not be the case, according to Dr. Steckel.
“Stanley Culpepper with the University of George, Allan York at North Carolina State University and I have conducted tests with these herbicides on 6-inch pigweed,” he said. “Liberty gave us 74 percent control; 2,4-D, 80 percent control; and dicamba, 83 percent control. That’s not good enough. If it’s smaller, you can do something with it, but it won’t do what Roundup did 15 years ago.
“You’re going to have to use a system to make it work where you’re using a pre herbicide with a postemergence herbicide whether it’s soybeans or cotton to achieve consistent control. Even with some of the traits that are a little farther off – like putting Halex on soybeans – you’ll need a pre to make it work.”
For more information on weed control recommendations, visit www.Utcrops.com/weeds/PDFs/2015WeedControl-Manual.pdf.