The Full Monty: A Case Study of Precision Management of Spring Dead Spot across an Entire Golf Course’s Roughs and Fairways By Caleb Henderson, School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA
The
clustered nature of spring dead spot (SDS) provides opportunities to reduce fungicide inputs by making precision applications using GPS spray equipment. Previous research from our lab has demonstrated success with targeted applications, first using manually created spray maps and subsequently using computer automated SDS detection both using drone images. On-course applications have been scaled from small-plot research to covering full golf course fairways, with successes and challenges with each phase of new research. The objective of our current study was to apply zonal or targeted applications of Kabuto across an entire golf course using a combination of developed approaches and determine the commercial viability of the process as it stands now. Drone imagery was collected across all in-play areas of the Independence Golf Club in Midlothian, VA while SDS was visible in Spring 2022. Disease patches were then detected, and their GPS coordinates were recorded using the computer automation methods we discussed earlier. Disease maps were made by drawing one yard di-
ameter circles around spots in the rough, and spots in the fairway were mapped into zonal treatments based on the density of the points. These maps reduced the area sprayed across the course by around 80% compared to a broadcast application. Targeted Kabuto applications were made from disease incidence maps were input into a John Deere ProGator 2020A Precision Sprayer in the Fall and results were collected the following Spring. While the process was possible it was not without its difficulties. Our first sprayer broke at the last minute, so we had to re-format all of the maps for a then unfamiliar sprayer, which took time. However, these issues were overcome, and the fungicide applications were made. The results in the Spring of 2023 showed severe winterkill in many areas, likely due to the uncharacteristically warm winter with several deep cold snaps in December and February. This also caused several patches that were treated to show up the following year, but these quickly filled in. Other patches persisted due some inconsistencies with our zonal treatment methods leaving gaps where disease went untreated. Limited new patches occurred in untreated areas that did not have SDS the previous year. issues were addressed and in Fall 2023 applications all detected SDS was treated with one yard diameter circles. Final results will be collected in Spring 2024. While the process overall is possible, there is still a lot of specialized knowledge required. At this time we would not recommend the average golf course to begin performing in house, but do not be surprised if private entities begin to tackle this issue in the near future.
Travis Roberson making a fungicide application at Independence Golf Club with John Deere ProGator 2020A GPS sprayer.
22 | VIRGINIA TURFGRASS JOURNAL January/February 2024 www.vaturf.org
