Perspectives Online

A Peach of a Solution. Fruitful Extension partnership results in new pesticide sprayer technology. By Suzanne Stanard.


Between rows of peaches near Candor, a tractor (above) pulls the pesticide sprayer, which has been calibrated more accurately and in half the time it previously required, thanks to a new method developed through the collaborative efforts of Dr. Gary Roberson, biological and agricultural engineering Extension specialist, and Roger Galloway, Montgomery County Extension agent, (below, back and foreground), as well as Dr. Wayne Buhler, Extension horticulture specialist.
Photos by Becky Kirkland

Montgomery County Extension agent Roger Galloway prides himself on staying abreast of the latest technology. He recognizes its value in his work and the vast potential it has to help farmers in his community. Galloway is inventive, resourceful and eager to try new things that will benefit farmers. That's why his latest innovation - a high-tech method to improve calibration of air blast pesticide sprayers - could be a boon to growers in Montgomery County and, if he gets his wish, across the state.

Air blast sprayers are used primarily for tree crops like peaches, plums and apples, but they're also used to protect grapes, blueberries and some vegetable crops from harmful pests and diseases. Pulled behind a tractor, the sprayer is a large cylindrical tank with a fan on the end that has 16 to 24 nozzles. A pump is used to supply spray solution to the nozzles at high pressure. Then, the fan uses high-velocity air to push the spray from the nozzles into the trees, coating them from top to bottom.

Calibrating the sprayers at least twice a year is critical, Galloway says, because it alerts farmers to faulty equipment that may be causing over- or under-use of pesticides. The typical method for calibrating an air blast sprayer can consume several hours for each sprayer, costing farmers valuable time and labor. To calibrate the sprayers, farmers collect liquid from each nozzle and measure it in buckets, a precision task that is difficult to pull off without getting soaked. Growers must then enter the measurements for each nozzle's output into mathematical formulas and hand-calculate the results.

To make it easier for farmers to calibrate their sprayers, Galloway has developed an innovative new method that cuts the time in half. And it incorporates computer technology that does the math for them.


Galloway teamed with Dr. Wayne Buhler (See related story) , horticultural science Extension specialist, and Dr. Gary Roberson, Extension specialist and associate professor of biological and agricultural engineering, to make his idea a reality. Together, they developed a system for calibration that employs a digital scale, hand-held computer and wireless printer - portable technology that produces results more accurately and much more quickly than the manual method.

"The beauty of this system is that is speeds up something farmers don't want to have to spend a lot of time on . even a half-day is a big loss," Galloway said. "We want to make this process as easy as possible for farmers. And, I think it's kind of nifty to stand here with the iPAQ (handheld computer) and print a document 30 feet away, without any wires connecting the two."

Buhler, who provides extensive expertise in pesticide use, as well as critical funding for the project, points out the financial - and environmental - benefits of the new system.

"Using less pesticide is advantageous to the grower in more ways than one," Buhler said. "Chemicals are often the most expensive part of their operation, and this also makes it possible for them to put fewer pesticides into the environment."

Galloway, Buhler and Roberson demonstrated the system in November, just after the last peach harvest at Garrett Johnson's family farm in Candor. Accurate sprayer calibration is especially critical to Johnson's peach operation, which picks seven days a week, never refrigerating the product, to deliver the freshest produce possible to consumers.

First, they attached short hoses to each of the nozzles on the sprayer. The hoses funneled the liquid into plastic buckets in 30-second or one-minute timed intervals. Then, each bucket was weighed on a portable digital scale. The three worked together efficiently, in an assembly line that Galloway jokingly referred to as the "bucket brigade." Galloway then plugged the data into a hand-held computer containing a scaled-down version of Microsoft Excel that is pre-loaded with the appropriate formulas. The program automatically calculated the results, and using "Bluetooth" radio frequency technology, transmitted the information to a nearby wireless printer.

The entire operation takes place out in the field, and in a matter of minutes, the grower has a detailed and easy-to-read report of the calibration.

Galloway also had placed bright yellow water-sensitive cards in the upper canopy of the trees before spraying. Dappled in blue afterward, the cards indicate how much - or how little - solution had covered the tree.

"The object is to have the pesticide on target," Galloway said. "The more off target the sprayer is, the greater the ramifications for the environment - and for the quality and safety of the fruit."

Roberson, an expert in precision technologies, teaches a variety of calibration trainings and has a deep personal and professional interest in finding better and more productive ways to use farm equipment. He handled the hardware side of this project and described the advantage of the new system as a "long-term cost-benefit relationship" for growers.

"The payback (for using this new calibration system) is an operation that is more environmentally responsible, more efficient in chemical use and produces a better overall product," Roberson said.

The system also has the potential to be a valuable teaching tool for farmers, Galloway said, because the report features all of the raw data and formulas, enabling them to go back and examine the specific factors more carefully - and to better understand how the results came about.

True to his resourceful nature and commitment to serving his growers, Galloway already has solutions in mind to tackle the project's only downside: the technology may not be attainable by many growers. He proposes that farmers invest in the technology together and share the equipment through cooperatives, or Extension agents could maintain the equipment and make it available to their growers. Galloway also suggests the idea of giving pesticide-training credits to growers who adopt the new technology.

Always thinking ahead, Galloway has explored newer and more advanced technologies that will improve the calibration process. But, he added, the most important factor isn't technology or equipment. It is the core of Galloway's work and the heart of Cooperative Extension: relationships.

"This is the way Extension works best," Galloway said. "Good communication between the specialist and the agent - sharing expertise and working together - helps growers solve problems."