Remember when glufosinate-tolerant soybeans were released? Folks quickly learned that confusing glufosinate- and glyphosate-tolerant soybeans could render disastrous results.
The same rules will apply for Roundup Ready 2 Xtend soybeans. After spraying a mixture that includes dicamba, tank cleanout is of paramount importance.
Monsanto's Seth Logan says the tank must be triple rinsed. This is in addition to taking the nozzles apart and cleaning the strainers and screens.
Logan showed some plots where the tank had been rinsed once or twice. It definitely wasn't enough.
For those who don't have time to rinse the tank three times, Monsanto is experimenting with a "deactivator" that essentially renders the dicamba ineffective. The results are encouraging.
Of course, drift is a major concern, even more so with dicamba. There will be stringent spray application requirements for the Roundup Ready 2 Xtend crop system. One requirement is a very coarse nozzle as the minimum for droplet size. In the Collinsville test plot, ultra coarse droplets provided the best drift reduction results.
At the field day, Logan pointed out the results of spraying a dicamba mixture in a traditional Roundup Ready soybean field with an XR nozzle, which produces a high percentage of medium and fine droplets (less than 150 microns). On the day of the application, the wind was blowing at 3 to 6 mph. With that nozzle, Logan saw symptoms of drift up to 50 yards away from the edge of the treated area.
Sara Allen, a weed management technology development rep with Monsanto, says the EPA is working to establish spray buffer requirements for Roundup Ready Xtend technology. Additionally, Monsanto will release a "Spray Manager Plus" app that will help applicators establish the proper buffer zones when spraying Roundup Xtend and Xtendimax.