Golf Course Management

APR 2019

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

Issue link: http://gcmdigital.gcsaa.org/i/1094722

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04.19 GOLF COURSE MANAGEMENT 81 Spring dead spot (SDS), caused by the pathogen Ophiosphaerella species, is one of the most destructive diseases of bermuda grass exposed to cold temperatures (3). Spring dead spot infects bermudagrass, predisposing the turf to isolated patches of cold-temperature damage. Although the primary pathogen in - fection occurs in the fall of the year when soil temperatures range from 50 F to 70 F (10 C to 21 C) (2), symptoms, including dead or thin patches of bermudagrass, are not present until bermudagrass exits winter dormancy in the spring of the year and may take months to recover (3). Symptoms can be isolated or widespread but generally reoccur in similar geographic locations from year to year (2). A recent survey of turfgrass managers in Virginia revealed that more than 80% of those surveyed were using chemical suppression tac - tics to combat spring dead spot, but that was not always the case. For several reasons, spring dead spot had, in general, not been chemically managed until the last 15 years. Increased demand for turfgrass quality, coupled with new hybrid bermudagrasses that were slower to recover from spring dead spot symptoms, prompted turfgrass managers to explore combatting this disease. Products that were labeled for spring dead spot suppression were cost-prohibitive to the majority of turfgrass managers until generic tebuconazole became available to the turf management market in 2011. At this point, it became common practice in the United States transition zone for turfgrass managers with a history of spring dead spot to make two to three applications of tebuconazole to all bermudagrass surfaces in the fall of the year. With inconsistent results, some golf course su - perintendents with access to greater resources began using more-expensive QoI, SDHI or combination fungicides to suppress spring dead spot. Although this method provided more consistent control, it was certainly cost- prohibitive to many and required multiple applications of fungicides. Turfgrass manag - ers effectively had three chemical suppression options: apply nothing, apply an inexpensive fungicide with inconsistent results, or apply an expensive fungicide with the hope of im - proved control. Site-specific management With these three imperfect options, we began to explore new tactics, including site- specific management, also defined as preci - sion turfgrass management (1). Site-specific management uses a variety of data inputs to make informed decisions on when and where to treat the turfgrass for maximum efficiency. As in large-scale crop production, turfgrass managers worldwide are interested in ways to improve input efficiency, especially in relation to the primary cultural practices, and to mini - mize any potential negative environmental ef- fects. An economic benefit from site-specific management in turf is more difficult to recog - nize than in crop production because inputs are not balanced by crop yields in turfgrass management. Inputs are balanced by human experience, environmental benefits and aes - thetics. ese factors are much more diffi- cult to quantify than revenue from harvested crops. Spring dead spot is a prime candidate for site-specific management because of its sin - gle life cycle per year, known infection timing and geographic reoccurrence of symptoms. Our goal was to explore the option of using Advancements in unmanned aerial vehicle aviation, GPS accuracy and global information system software make aerial maps a feasible option for superintendents to evaluate their golf course rapidly at a given time. Photo by David McCall

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