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Turf Talk
Targeting Sustainability
GPS-guided sprayers in golf course management by ELISABETH KITCHIN, SHAWN ASKEW, and DAVID MCCALL
Putting precision to the test At Virginia Tech, the research labs of Drs. McCall and Askew are working to fill these knowledge gaps by evaluating the accuracy and precision of GPS-guided pesticide applications. Specifically, we investigated how factors such as sprayer travel speed and target size influence the effectiveness of targeted treatments.
We conducted our study on a fairway at the Virginia Tech Golf Course in Blacksburg. We marked intended spray targets on the turf with neon orange paint, ensuring each target’ s center was precisely mapped. Target sizes ranged from 1.5 feet to 6.5 feet in diameter to represent realistic scenarios— from
The Virginia Tech
Turf Team works to capture drone images of UV dye deposition.
Turfgrass managers and golf course superintendents are increasingly interested in precision management technologies, especially as environmental sustainability becomes a higher priority in the industry. One promising approach is the use of GPS-guided sprayers to make targeted applications of pesticides and fertilizers only where they are needed.
Consider the magnitude of reducing chemical inputs, costs, and potential environmental impact on a large scale when treating only the affected areas of a fairway rather than making broadcast applications course-wide. Despite this clear potential, however, uncertainty remains about how consistently and accurately these systems perform under typical field conditions. small disease patches to larger weed infestations. Instead of pesticides, a Toro Multipro 5800G sprayer equipped with GeoLink Precision Spray technology applied a mixture of biodegradable fluorescent dye( commonly used to trace leaks in plumbing systems) and water. Under ultraviolet( UV) light, the dye glows vividly, allowing us to pinpoint exactly where the sprayer deposited the solution.
We tested three sprayer travel speeds: 3, 4.5, and 6 mph. After treatments, our team illuminated the plots at night with UV lights and captured high-resolution drone imagery, clearly revealing spray deposition patterns. By comparing the fluorescent deposits to the originally marked targets, we quantitatively assessed both accuracy( how closely the spray matched the intended target area) and precision( how consistently this accuracy was achieved under different conditions).
Technology that pays off The results offered valuable insights for turfgrass managers considering GPS-guided sprayers. Overall, the sprayer demonstrated impressive accuracy and reliably hit intended targets. Target size had no significant effect on accuracy or precision, suggesting these systems can effectively treat both small disease outbreaks and larger infestation zones. This is particularly beneficial for site-specific management, reinforcing the value of precise applications regardless of infestation scale.
Sprayer travel speed, however, significantly influenced performance. Treatments at the slower speed of 3 mph resulted in less precise applications, often depositing spray slightly offset from the intended targets. In contrast, applications at 4.5 mph and 6 mph consistently achieved high accuracy, with spray deposits closely aligned to target areas. This finding challenges the common assumption that slower speeds yield greater accuracy. Instead, moderate-to-faster speeds appear optimal for maintaining both accuracy and efficiency in targeted applications.
The takeaway for golf course managers and turfgrass professionals is clear: GPS-guided spraying technology can be a reliable and practical tool for precise pesticide applications. By selecting optimal application speeds, managers can confidently use these systems to reduce inputs, manage pests more effectively, and support environmental sustainability. Through continued research, Virginia Tech’ s turfgrass team aims to provide superintendents with practical guidance that promotes wider adoption of precision turfgrass management practices— ultimately helping deliver healthier turf and better-playing conditions for golfers.
VIRGINIA TECH
10 V IRGINIA G OLFER | J ANUARY / F EBRUARY 2026 vsga. org