What's the drift when it comes to pesticide application? Well, it's the same old challenge. The smaller the droplet is the more the product lingers where you don't want it to linger. However, smaller droplets penetrate the turf's canopy better and provide uniform coverage.
It's vital that superintendents make sure the speedometer on a sprayer is accurate to the ground speed that it's traveling.
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"That's the great paradox," says Wayne Buhler, a professor and pesticide safety extension specialist at North Carolina State University.
That said, technology has and continues to improve in the goal to achieve maximum application efficiency while minimizing the risk to applicators and the environment. Golf course superintendents need to stay abreast of the technology for their own good.
"Golf courses are certainly in the crosshairs of environmental protectionists," Buhler says. "It's wise for them to be aware of this technology."
Will Smart, CEO of Greenleaf Technologies, which manufactures high-tech spraying equipment, says superintendents who want to improve application efficiency are paying attention to new technology.
"They are spraying some expensive products and filling that spray tank with a lot of money," Smart says. "You can have the fanciest sprayer in the world, but if you don't have the right nozzle on there to deliver the right droplet size and to hit that target and cover that target, you're wasting time and money when it comes to getting maximum efficacy out of those products."
Syngenta Research Scientist Dan Kidder agrees, noting that some superintendents realize that application efficiency will only help them keep their costs down. Kidder is impressed with the improvements he's seen in application equipment.
"Newer sprayers are much easier to calibrate than the older ones," he adds. "They usually come with a good set of nozzles, and the ability to adjust boom height has really improved."
But the ability to use the new sprayers at their optimum ability is what's lacking in many circumstances, Kidder notes. Many superintendents aren't sure what type of nozzles they should use for certain situations. They're also not sure what water volume to apply to get the best performance of their products.
Laurence Mudge, manager of the Green Solution Team for Environmental Science, a division of Bayer CropScience, is impressed with improvements made to application equipment, especially with nozzles.
"It's almost like precision application," Mudge says. "The technology has come a long way. We're doing a good job of applying pesticides. But that doesn't mean we can't do better."
Superintendents need to do better with nozzle selection, Smart says.
"It's all about educating them on nozzle selection from the standpoint of getting the right droplet size, operating with the right pressure and looking at different types of trajectories that are coverage sensitive, like contact fungicides, foliars and colorants," Smart says.
The flat-fan nozzle has been to the "go-to nozzle" for many years and features a fine droplet, Smart says. Greenleaf Technologies offers the TurboDrop, an air-induction nozzle that debuted about 12 years ago, which superintendents give solid reviews. It was designed to achieve a larger droplet size with the help of air. The air causes the droplet to splatter and achieve good contact. Even in a 10 mph wind, the nozzles will place droplets where they're needed, Smart says.
Smart says he knows superintendents who spray greens in one direction and then turn around and spray them in the other direction to get better coverage on both sides of the leaf blade, which he notes is a vertical target. To help them do that more efficiently, Greenleaf Technologies introduced the TDTW TurboDrop TwinFan nozzle, which covers both sides of the leaf blade.
Maximizing coverage through trajectory is the next step in achieving maximum efficiency, Smart says.
"You can only go so far with droplet size, but trajectory is something we can really enhance," he adds.
Spraying efficiency can also be improved by direct injection, Kidder says. Direct injection means the spray tank only holds water. However, a jug of pesticide concentrate is hooked to the spray tank with a tube for the pesticide to be metered into the spray line as the sprayer vehicle moves.
"There are several reasons why this creates a big advantage," Kidder says. "One, you never have to clean out a spray tank because there's only water in it. Two, you never have leftover product mixed in the tank when you get done spraying the golf course. It just meters in as you need it."
There's also less worker exposure to pesticides because direct injection is a closed system, Kidder points out.
Do their part
Superintendents shouldn't just rely on new technology to achieve more efficient pesticide application. They also have to do their part.
For example, it's vital that superintendents make sure the speedometer on a sprayer is accurate to the ground speed that it's traveling. They should spray when the wind is blowing 2 mph to 4 mph.
"Something less than 2 mph can be conducive to temperature inversions," Buhler says.
With temperature inversion, there's a layer of warm air on top of a layer of cool air, and the spray particles aren't mixed in the air very well because of the warm air.
"They hit a glass ceiling, if you will," Buhler says.
Bob Wolf, a sprayer technology consultant, says it's important to maintain sprayers in good condition, which includes proper calibration. But Wolf says he has heard superintendents say, "I don't have time for that," when it comes to calibrating sprayers. But he insists that superintendents need to find time for it.
Mudge says proper calibration is vital so superintendents know exactly what the spray volume is.
"[Chemical companies] recommend [a certain amount] of product per 1,000 square feet or per acre," Mudge says. "That's assuming they're using calibrated equipment. If we say 3.2 ounces per 1,000 square feet, that's what we mean."
Kidder suggests superintendents check a sprayer's calibration two or three times a year.
"If there's any big change - like you use different nozzles or go to a different spray volume or you're changing your speed dramatically from one type of product to another - you need to check calibration on the sprayer," he adds.
Kidder also stresses the importance of using the right nozzle for the right product. He has seen too many superintendents use the same nozzles to spray different pesticides on different parts of the golf course, which is a no-no.
"Most of our labels will tell you what kind of spray droplet there should be, and that's determined by the type of product you're using," he adds.
While Mudge says superintendents generally do a great job of applying pesticides, there are cases when they over-apply or misapply them or they use the wrong nozzles.
"It depends on what type of pesticide you're using," Mudge adds. "You have to have sufficient spray volume for enough leaf wetness with postemergence herbicides. Whereas with a pre-emergence herbicide it's not as important, just so long as the spray is uniform. Sometimes spray volume is important, and sometimes it's not. Sometimes sprayer tip or nozzle selection is important, and sometimes it's not."
Superintendents also need to know when to replace worn nozzles, which is sometimes difficult to tell, Wolf says. Superintendents can tell if nozzles are worn by measuring their output and analyzing pattern quality.
"If either one of those are off the standard, that's when you need to replace them," Wolf adds.
Kidder says some superintendents are using the same nozzles on sprayers even after five years, not realizing the nozzles have worn out.
Superintendents can measure the output of a nozzle for 30 seconds or a minute to see if it needs changing. If it's more than 5 percent from the average output, it needs changing, Kidder says. They can also spray water-sensitive paper to see if nozzles are worn. If the water droplets aren't uniform, the nozzle is worn.
Mudge understands why superintendents elect to load their tanks with several products for one spray. It's about time and money. "I wouldn't want to spray three or four times when I can just do it once," he says.
But Mudge is concerned that superintendents are mixing too many products - including herbicides, fungicides, insecticides, fertility products and plant growth regulators and adjuvants - in the spray tank, which is causing application problems, including the increased risk of phytotoxicity and reduced efficacy. Chemical companies test product for plant safety, but can't possibly test all of the spray tank mixtures that can be done.
"You have all these products in the tank, and they aren't compatible with each other," Mudge says.
Sometimes a superintendent will spray a mixture of several products a few times and not have any problems. Then he'll spray the same mixture again and there will be a problem. And he might blame the problem on a "bad" product, Mudge adds.
But if the environmental conditions changed for the last spray, the turfgrass may have been overly stressed, which led to the problem. "Nobody has done any research on this," Mudge says. "We should be thinking more about it."
Mudge recommends that superintendents at least do jar tests to test the compatibility of products, and are careful with putting too many products into the spray tank.
Aylward can be reached at 330-723-2136 or email@example.com.