Changing Crop Protection Landscape Demands Drift Advances
May 1, 2014 
Dealers and growers need to be more careful than ever about drift control and spray efficacy.
Drift control and spray application efficacy are entering a whole new era. So says Tim Stuenkel, global marketing communications manager at TeeJet Technologies, and many of his colleagues agree. With the new cropping systems coming on line in the next few seasons — utilizing more herbicide-resistant crops, for instance — and widening/rising consumer concerns about the environment, dealers and growers will need to be more careful than ever about off-target product movement.
Fortunately, manufacturers and universities continue to come up with innovations in three key areas: sprayer component design, crop protection chemistries and tank additives.
Pattern Master
The newest technology editors at CropLife® have come across is the Pattern Master brush system from K-B Agritech, LLC, based in Plainfield, WI. The tool is the brainchild of Kurt Kamin, veteran farmer and sport pilot. His design was based on the physics he saw in the aerodynamics of airplane flight — principles that also apply to sprayers in a field.
When the air hits the front of a sprayer boom as it moves, whether there’s a wind in the field or it’s a dead calm day, a high pressure area is created in front of the boom. As that high pressure travels around the boom, it’s moving to an area of low pressure, and the air actually accelerates. “So if you’re going through the field at 12 mph, you could have a 15 to 16 mph wind hitting your spray pattern,” says Kamin. That wind creates a shear factor on the spray pattern.
Kamin’s solution is to put brushes in front of each nozzle to deflect that turbulence, thereby eliminating a significant amount of drift. In fact, by eliminating that shear factor on the spray, the pattern can develop for about a third of its life unobstructed.
“Ecologically it’s friendlier for everybody because you hit your target. Economically it’s going to be extremely friendly because it makes you more efficient,” summarizes Kamin.
More testing will show exactly what percentage of drift is being eliminated, but Kamin is confident about the results.
The Pattern Master is so promising, it’s captured the attention of both Bob Wolf, drift expert/owner of Wolf Consulting & Research, and Monsanto, creator of the Roundup Ready 2 Xtend crop system. The system features soybeans tolerant to both glyphosate and dicamba. Monsanto will be tracking trials scheduled for this summer on soybeans that will quantify the brushes’ spray pattern protection.
A modern, full-size sprayer boom (120-feet, 20-inch spacings) can be equipped with a complete set of the Pattern Master units around $3,950.
More Spray Precision
While the technology of Pulse Width Modulation (PWM) control is not new — Case IH introduced the AIM Command System on its Patriot sprayers several years ago — the concept is gaining more attention recently.
Last summer, Case IH debuted the AIM Command PRO spray system, which offers constant rate and pressure over a wide range of speeds. Nozzles can be turned on and off one at a time, rather than entire boom sections. This “minimizes skips, overspray and overlaps, preventing over-application and the resulting crop damage,” says Mark Burns, Case IH application equipment marketing manager.
Wolf says the PWM technology has always been a useful tool, but in his training workshops, he’s discovered it’s getting more and more popular with users. In fact, he promotes the system at his meetings, demonstrates it and assures applicators the tool is a good investment.
TeeJet Technologies has been looking at PWM for many years, but recently decided to “pull the trigger on it because the timing is right,” says Stuenkel. “The market is accepting of it, for the cost and benefits.”
TeeJet’s product, the DynaJet Flex 7120 PWM Sprayer Control will be available later this year.
With the system, TeeJet’s solenoid bodies are mounted on every boom salvo body. The solenoids have actually been on the market for several years for individual tip shut-off or section shut-off, so it’s a proven solenoid package, says Stuenkel.
“In conjunction with the DynaJet Flex controller, we can pulse the solenoids 10 times per second,” he explains. “By adjusting the duty-cycle on the solenoids, we can maintain a fixed pressure in the boom, as field speed increases or decreases — rather than increasing or decreasing the flow pressure to get the flow rate.”
Stuenkel says drivers can be more productive, putting down a full, appropriate rate even when they are slowing down to 4 mph at the end of rows or going 18 mph in the middle of the field. Applicators can also select a specific droplet size and maintain that throughout application.
With new weed control systems, “there’s going to be a lot more droplet size spray management needed, so you don’t have 2,4-D drifting on your neighbor’s crops that may not be 2,4-D ready,” Stuenkel points out. The industry needs a technology that can do this effectively and efficiently, so someone doesn’t have to get out of the cab all the time and adjust tips, he says.
The DynaJet Flex system is designed to piggyback on to existing rate control systems. Its compact, touchscreen display, mounted in the cab, allows for easy set-up and operation.
Challenges Of The New Systems
The dicamba- and 2,4-D-tolerant cropping systems may be in demand by growers, but it’s going to take a whole lot of education in application techniques — including droplet issues and particle drift — to make them effective.
“Labels are going to start specifying the spray quality or droplet size, in particular telling users to put on a coarse or very coarse drop, and they have to learn how to do that,” says Wolf.
Chemical manufacturers have worked extensively to engineer some of the products for less volatility, plus their experts know exactly how to get the size of droplet that will 1) kill the weed and 2) minimize drift, he notes.
“I think they’re going to err on the side of safety and probably call for a little bigger droplet than they might need because they don’t want drift,” says Wolf. He is concerned that if drift control is the industry’s number one goal, applicators will lose sight of the other very important goal in application: Killing the weed with the best coverage.
Some of the new nozzles are designed to reduce drift already, and if applicators lower sprayer pressure they may reduce drift even more — but coverage is also reduced. Over the past few years, Wolf believes this lack of coverage has played a part in some resistance problems.
“We’re trying to get some of the applicators using this new nozzle technology to spray at higher pressures. But that kind of goes against the educational philosophy for years and years and years that low pressure means less drift,” he says.
Recordkeeping for new weed strategies will also become even more crucial, as growers try to avoid hitting fields of non-tolerant crops with inappropriate chemistries or inadvertently allowing drift to reach susceptible crops. Wolf points out that as the industry introduces dicamba, 2,4-D, HPPD, ALS and sulfonylurea “ready” technologies, “how many programs and systems are we going to have to work around? It’s going to be recordkeeping headache for one thing, and it will mean a lot more different tank mixes.”
Speaking of tank mixes, Brian Kuehl, product development manager, West Central Inc., Willmar, MN, represents another drift technology segment evaluating the new weed control technologies: additives. The company is a wholesale distributer of crop inputs, including nearly a dozen adjuvants. With additives, “you not only have to be aware of droplet size, but you also have to be aware of the impact you’re having on the chemistry from a vapor or volatility standpoint,” he says. “West Central is working very hard with the manufacturers of these new weed technologies to make sure we have the right additives.”
Chris Reeves, Kuehl’s colleague at West Central, says tank products will continue to evolve and improve. How they work with application equipment, nozzles and pesticides are an “untold story.” He notes that some products look great in lab conditions, but become a problem when used in a commercial setting. They may encourage quick breakdown due to pump shear, be difficult to handle in some environmental conditions, not mix with fertilizers or need to be used at rates that are inefficient for the applicator.
One company that is carefully watching how the new weed control systems play out is The Andersons Inc., Maumee, OH. In 2012, CropLife reported that the firm had developed a breakthrough application technology: herbicides applied via water activated granules. “We’re trying to solve for drift,” says Chuck Anderson, director of professional products for the company’s turf and specialty group. The concept has been well-proven for efficacy, but finding commercial partners has been a challenge. “The granules have to be applied pneumatically because they’re so small,” he explains. The Valmar-type or airflow-type technology is out there, but it’s not in widespread use.
In fact, granules containing gly-phosate, dicamba and 2,4-D have been developed.
Anderson hopes the new weed systems are successful, but if there are some regions where more conventional spray technology won’t work, he’s hoping industry stakeholders will take a second look at granules, “which are on very few people’s radar.” In California, for instance, so many crops are in close proximity, applicators may need the added precision that granules can deliver, he says.
EPA’s Role
EPA has become a key player in the drift debate, in particular with the introduction of its Drift Reduction Technology (DRT) program in 2006. The program’s goal is to encourage the industry to adopt technology to lower drift and setback requirements. EPA has offered a number of public comment periods, the last of which closed in January 2013.
A key component of the program is a “star” rating system for products like the one used in other parts of the world, including Europe, for years.
According to EPA’s Cathy Milbourn, revisions to the proposed product test protocol and program operations are undergoing internal review now. Later this year, the agency plans to publish the Federal Register Notice announcing the start of the DRT program. (The final DRT Webpage will post when the Federal Register Notice announcing the start of the program comes out.)
West Central’s Kuehl — who has carefully tracked the program — believes EPA has done a very good job working with both academia and industry in order to come up with a system that effectively evaluates products. He seems agreeable to the wind tunnel testing, for instance, that will be needed for the company’s products to get a DRT rating.
Reeves feels the program will “sort out all the chaff” in drift reduction claims. “Scientifically sound testing methods for all technologies will be good for the industry and should give retailers and growers the best information to reduce drift issues,” he says.
Reeves has prepared an extensive and helpful presentation on the DRT situation, which he gave at the South Dakota Agri-Business Association’s agronomy conference late last year (www.sdaba.org/agronomyconference/pdfs/2013ReevesDrift.pdf).
Bob Wolf, who’s also been following the program for several years, thinks it’s a “good idea” but is discouraged about the years it’s taken to develop.
Wolf is also concerned about the time and money companies are going to have to invest in proving their products to EPA in the agency’s testing. “It’s going to be an expensive way to collect new data,” he notes, with no credit given to the large amounts of work and testing that has already been done by many companies such as nozzle manufacturers. “Agriculture has a lot of small-time entrepreneurs who have developed drift reduction technologies. They may not be able to afford all it takes to get the products into the DRT program,” he says.
Dr. Greg Kruger, cropping systems specialist at the University of Nebraska’s West Central Research Extension Center, thinks the DRT approach is “really good at simplifying things.” Applicators that are using some sort of drift reduction technique/technology can quickly look at EPA’s ratings for an item and see how well it should perform.
Kruger is actually a manager of the university’s wind tunnels, which have already become key testing grounds for many drift products’ performance.
The Public’s Role
EPA may be vested in drift reduction, but many public organizations are vitally interested as well — as often evidenced by extension national media coverage. One example is the Pesticide Action Network (PAN) North America, which “works to replace the use of hazardous pesticides with ecologically sound and socially just alternatives.”
The group, based in Oakland, CA, with a Midwest office in Minneapolis, MN, has created a program called Drift Catchers. With funding from supporters, PAN gives special monitoring units to communities to collect air samples, which are then sent to a lab for analysis. The testing finds what pesticides are in the air and at what level. The goal is to prove dangerous pesticide drift and rally citizens to change local and state policies on applications.
PAN North America has sponsored 27 projects in nine states since the program’s beginning in 2008, some of which have indeed impacted policy.
“Applications with absolutely zero drift-able droplets are extremely difficult to achieve,” says West Central’s Kuehl. “I think it comes back to the tolerance and awareness of drift potential, what do we consider acceptable thresholds?”
Many groups are also concerned about wildlife, most recently bees. That’s where an ag industry program like the DriftWatch Specialty Crop Site Registry — now operated by FieldWatch — can help. It not only gives applicators in nine states the location of pesticide-sensitive crops, it shows registered apiaries. One challenge: Wolf has found that many beekeepers don’t like to release their locations. “They can be secretive,” he says. “They don’t like to let people know where they keep their moneymakers, so that defeats the DriftWatch’s purpose. The only way to keep pesticides away from their bees is if applicators know where they are.”
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