By Dr. Larry Steckel, University of Tennessee Extension Weed Specialist
The fifth blog on stewardship of XtendiMax and Engenia on Xtend crops will revisit nozzles.
On February 17, the EPA approved the use of 20 other nozzles and/or orifice sizes besides the TTI 11004 for XtendiMax. The additional nozzles on the list are good with respect to having more options. But keep in mind that the nozzles are only approved if used at the designated operating pressures listed on that website.
As a result, I do not think we should be moving from Spraying Systems’ TTI nozzles to their AI nozzles. The reason for that is the operating pressure for AI11002, AI8002 and AI8005 must be between 30 and 40 psi to stay on label. I fear as folks get into a hurry (which we all know will happen at some point) and increase their speed, it will result in operating pressures that ramp up well above 40 psi. These higher pump pressures will cause those AI nozzles to produce a lot of fine droplets that will readily drift.
I am not sure how many AI nozzles are still out there, but these would be the last choice I would consider out of the nozzles on that list.
Similarly, other nozzles on that list that are only labeled to be used at a narrow pressure range, like the Lechler ID nozzles, would also concern me. The Lechler nozzles are only approved to be used between 30 and 40 psi, which is hard to do if you are in a hurry or indeed just trying to spray some of our rolling hilly fields.
On the other hand, I was glad to see the Greenleaf TADF and TDXL nozzles were added, as we have evaluated them for several years and they have proven to be good nozzles. Moreover, they have a pretty good pressure range that they can be operated at and still be on label.
Finally, I was very happy to see that the Wilger DR11010 was added. This non-air induction nozzle will let those sprayers using the Pulse Wide Modulation (PWM) system, like the Aim Command, to run as intended with solenoids and not pump pressure controlling the flow rate. I am a believer in the PWM sprayers, as the pressure remains constant even at higher speeds, which can greatly help mitigate drift.
Before the DR nozzle was cleared, the only choice folks running PWM systems had was to shut the PWM system off and use an air induction tip. Though that is workable, now they have the PWM option when spraying XtendiMax. Unfortunately that is not yet the case for Engenia. Hopefully, that will change before we go to the field.