As we get further into the year, bugs begin to enter our fields, disease onset starts to occur, and weeds continue to flourish, our chances of making tank-mixed applications increase. This ultimately makes spray nozzle selection more challenging as most products require different droplet sizes.
Spray nozzles directly affect the size and uniformity of droplets. Most product labels specify which droplet size, typically medium to coarse, works best in different scenarios. While there are many great nozzles on the market, there is not one specific nozzle that works to the best potential for each individual product. Most commercial sprayers of today come equipped with at least a 3-way nozzle turret giving us the flexibility to have a good spray nozzle option at all times for each application.
One of our biggest issues with spray applications is off-target movement or spray drift. This results in poor product efficacy and sometimes crop damage in neighboring fields. As our ground speeds get faster and our pressures rise, we may want to consider other nozzles than our usual flat fans of old. Also, these nozzles producing small droplets will not be labeled for use in future crops tolerant to herbicides like dicamba and 2,4-D.
Contact pesticides require very good coverage, which can be achieved by using high spray volumes (15-20 gallons per acre) and medium size droplets. Nozzles to consider when making these applications would be nozzles such as TeeJet’s AIXR (Air Induction Extended Range), Greenleaf’s Airmix, and Hypro’s Guardian Air. These venturi-style nozzles create air-filled droplets that minimize off-target movement while still achieving adequate coverage in medium to coarse droplet sizes.
Systemic pesticides also require adequate coverage, but work better when applied in coarse to very coarse droplets. By still having good efficacy with larger droplets, we have increased insurance of reduced off-target movement. Nozzles to consider when making this type of application would be Teejet’s TTI (Turbo Teejet Induction), Greenleaf’s TDXL (Turbodrop), and Hypro’s ULD (Ultra-Low Drift). These nozzles use combinations of pre-orifices, air induction, and/or deflectors to create larger droplets.
When making tank-mixed applications of contact and systemic pesticides, nozzle selection can be a little tricky. One idea would be to use the nozzle on your turret that produces the best overall coverage. Other nozzles to consider for tank-mixed applications would be dual fan nozzles. With these type arrangements, we can select nozzles that produce coarser droplets or both coarse and medium droplets. By having twin fans, these nozzles have improved coverage over single fans, and when selecting for a coarser droplet, we can also minimize our off target movement. Most nozzle manufacturers produce their single fans in a twin fan arrangement. Some dual fan nozzles to consider are Greenleaf’s TADF (Turbodrop Asymmetrical Dual Fan), Teejet’s TT Duo (Turbo Teejet Duo), and Hypro’s Guardian Air Twin.
There are many other manufacturers that create excellent nozzles other than those listed here. All nozzle manufacturers provide tabulation charts in their product guides that include droplet size and spray volume at all given speeds, pressures, and nozzle spacings. The biggest thing we need to do when choosing our nozzles is be mindful of what droplet sizes at our desired speeds and pressures are produced for our various types of pesticide applications.