Dicamba on soybeans
Are any of you using the dicamba-tolerant technology this year on soybeans? It hit some bumps last year with illegal application use in Missouri and there are a number of precautions applicators need to take before using it compared to other herbicides in nozzle type, tank/hose cleanout, etc.
I wonder if the additional work will deter some from using it. On the other hand, it's my understanding that it's pretty good technology from the control/management end, too.
Crops Technology Editor
Re: Dicamba on soybeans
Got this of Ag Web -
As farmers across the Midwest prepare for postemergent spraying, southern states report new dicamba formulations won’t be a silver bullet to all weeds. Palmer amaranth’s resilience is proving to be more challenging than farmers expected and begs for farmers to follow the less than 4” guideline.
“What I can say is that the perception many have that dicamba will control Palmer amaranth like Roundup did in 1996 is causing a lot of disappointment,” says Larry Steckel, University of Tennessee Extension in a recent blog post. He’s heard similar sentiments from colleagues in Arkansas and Georgia.
His field visits show applications when weeds are 2” to 4” and a few near the 6” show only 50% Palmer amaranth control in some areas. Survivors were twisted and took a couple weeks to begin growing again after application, Steckel says. “In our research a sequential application of Engenia, Xtendimax or Liberty (in Xtend cotton) about 14 days after the first dicamba product application removed all the crippled pigweed.”
Engenia, FeXapan and Xtendimax labels explicitly state weeds should be no more than 4” tall for maximum control. Because Palmer amaranth can grow up to 2.5” per day in certain conditions it’s important to scout frequently and spray herbicides as soon as weeds emerge. Residual herbicides can extend control.
What do you do about Palmer escapes? In cotton, follow dicamba with Liberty, and in soybeans the only option is Engenia, FeXapan or Xtendimax, according to Steckel. “If you want to get good Palmer amaranth control with one application target one to two inch Palmer—if you wait until some pigweeds are four inches tall plan on having the sprayer back to the field in two weeks.”