"May you live in interesting times," is a reputed Confucian curse. The spray industry is definitely cursed, as post-emergence crop protection just keeps getting more and more interesting. New products, reformulated products and new combinations of products are hitting the market almost every day. Luckily for applicators and their customers, new nozzle technology and a better understanding of the role nozzles play is hitting the market as well.
Mike Collins has seen it all, from his days as a custom applicator to his current role as Midwest sales manager, CP Products. "Post-emergence application really came on with glyphosate and the drive to high-capacity sprayers," he said. "With the range of new herbicide-tolerant traits and accompanying products, as well as other pesticides that these sprayers are being used for, we are also seeing the need for a range of nozzle tips as companies call for an equally broad range of droplet size that provides product efficacy. We believe multiple orifice nozzles are the key, so you don't have to carry and change out multiple nozzles depending on what droplet size is recommended."
Collins noted that variable rate nozzles are starting to come along, but they tend to still be in the coarse droplet range. He points to the new six-orifice CP Sprayer Turbo Nozzle, with three deflectors for 18 possible settings of post-emerge applications, as providing a greater range of options. Change orifice, and you change the rate. Change the deflector, and you change the droplet spectrum. An eight-orifice version is also available for floaters and pre-emerge use.
Carolyn Baecker, CP Products president, pointed out how vital a range of options is in the new world of post-emergence application. "Multiple products in the tank mixes have a huge impact on droplet spectrum and whether a particular mix creates more fines under 200 microns that drift," she said. "The problem is you can't research every tank mix. It is simply not possible."
Baecker said the company is working on variable rate technology (VRT) nozzles, but questions if VRT is a good idea as applied to pesticides. "If you put enough on to control a problem in one area, but cut back in another, are you simply giving those pests a vaccination that can lead to more resistance?" she asked. "These are the kinds of unintended consequences we need to consider. At the same time, these challenges also produce unintended opportunities."
The idea for the multiple orifice Turbo nozzle came from aerial customers, recalled Baecker. They requested high volume capacity and the ability to change rates without stopping to change nozzles.
"They were total failures for aerial use and didn't even get off our test boom," she said. "However, the concept turned out perfect for our sprayer turbo, so we adapted the patent for that use. Our higher volume model goes up to 3.3 gallons at 40 psi."
Tim Stuenkel, global marketing communications manager, TeeJet, agreed that changing market needs due to new products and combinations of products are driving nozzle development.
However, one thing hasn't changed. "Certainly the ability to control droplet size and flow rate independent of each other remains the Holy Grail in tip technology," he said.
Stuenkel pointed to the higher degree of regulation and rules in place in Europe as driving technology for drift control and efficacy that will find its way to North America. He said, “Bi-fluid nozzle technology, like our AirJet system, has been in use for years in Europe and Australia allowing operators to select droplet size independent of flow rate. However, I expect other technologies, still under development, will be more appropriate for the North American market.”
Stuenkel noted that monitoring flow rates at individual tips is also getting more attention and likely to become an important feature in the near future. "We are also likely to see shorter boom sections and ultimately single tip shutoffs," he said.
"The biggest trend we are seeing is concern for off-target spraying," said Mark Bartel, Wilger. "I can remember when droplet size was never questioned. Now the first or second question is, 'Do you have a tip that can reduce drift?'"
Bartel said Wilger tries to make it easy for applicators to ensure they do have the right tip. A few years ago, the company introduced its online Tip Wizard. Viewers could go online and plug in information for each application. They get options for tips with droplet size and drift information in microns, not the common coarse, fine or very fine descriptors.
"Tip Wizard also shows what happens as you change speeds and then change pressure to match the speed and what that does to droplet size and added fines," said Bartel. "It makes it easier to match the tip to fit label recommendations."
Bartel noted that the Tip Wizard now is also available as a smart phone app. Go to iTunes and search for WilgerTipWizard and download it for free. Tip Wizard can also be accessed at www.tipwizard.net.
Stuenkel noted that operators need to move beyond droplet size when it comes to controlling drift. "As operators move to other modes of action and increased tank mixes, they need to be smarter and more diligent in tip selection," he said. "There is a wholesale shift in nozzle selection starting that will be more and more prevalent. We have to re-educate applicators about tip selection. We are also launching our Spray Select tip selection mobile phone app this spring that we hope will prove to be a very handy tool for growers."
Stuenkel emphasized the need for balance between drift control and coverage. He added that applicators also need to better understand the differences between a systemic, locally systemic or translocator contact product and the type of tip needed for each at a particular stage of crop growth.
"Our biggest droplet size produced with our Air InductionTurbo TeeJet is intended for high levels of drift control, is targeted at a systemic herbicide like glyphosate, but would be a poor choice for a contact herbicide," said Stuenkel. "Our AIXR tips offer good drift control, but with a finer droplet size that is good for a systemic-type chemistry. They provide increased coverage particularly at low water rates or on vary small grasses or small stage of growth weeds. With contact products like Liberty, Ignite or fungicides, our Turbo Twin Jet gives lots of coverage."
The question gets tricky with tank mixes where recommended tips differ for each product. Wilger introduced its Combo Rate series designed for those situations. It divides the flow with 50 percent being applied through each of two tips.
"We tried it last fall and again early this spring, but the jury is still out on the concept," said Bartel. "However, University of Tennessee tests did show positive results. The two tips tend to fill in the center between the two droplet sizes."
The Combo Rate tips also work well for fungicide, insecticide and defoliant sprays. Bartel noted that a finer drop tip promotes good coverage of the upper canopy, while larger drops penetrate to the lower canopy and even to the ground.
"Rusts, fungi and insects are in the lower part of the canopy, and, of course, you want to defoliate an entire plant, so penetration is vital," said Bartel.
TeeJet is taking a different angle—literally—to enhanced canopy penetration. "We just launched the AI370 this past February, targeted for fusarium control in the small grains market," said Stuenkel. "Its 30-degree forward tilt penetrates dense canopies, while the 70-degree rear tilt covers the seed head and upper stalks. The venturi air aspirator produces drift resistant drops."
One thing is certain. Crop production technologies will continue to evolve, nozzles will as well and agronomic approaches will change. "Everyone thought that with gene modification of seed, we wouldn't have problems with pests, and some wondered if the spray industry was going to go away," said Baecker. "Instead, now we find that if we spray corn at a certain stage with fungicides, we increase yield. As a result, the spray industry expands. That's one of those unintended consequences and opportunities."