Golf Course Management

DEC 2012

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/95639

Contents of this Issue

Navigation

Page 83 of 125

research Irrigation timing Bayleton FLO (1 ounce/1,000 square feet) Triton 70 WG (0.25 ounce/1,000 square feet) No fungicide 600 2008 500 400 300 200 100 0 Immediate 10 hours later Immediate 10 hours later Figure 2. Effect of irrigation timing on prevention of fairy ring caused by Vascellum curtsii in 2008 and 2009. AUDPC = Area Under the Disease Progress Curve, a measure of the total fairy ring occurrence from May to September. Irrigation timing had no effect on fungicide performance. Wetting agent tank mix Bayleton FLO (1 ounce/1,000 square feet) Triton 70 WG (0.25 ounce/1,000 square feet) No fungicide 500 450 400 350 300 250 200 150 100 50 0 w/ Revolution w/o Revolution w/ Revolution w/o Revolution Figure 3. Effect of wetting agent tank mix on prevention of fairy ring caused by Vascellum curtisii (AUDPC). AUDPC = Area Under the Disease Progress Curve, a measure of the total fairy ring occurrence from May to September. Treatments were applied twice in the spring on March 28 and April 25, 2008, and March 31 and April 28, 2009. Within a year, bars with the same letter are not significantly different from one another. Data in this research suggest that tank-mixing a surfactant with a preventive fungicide does not increase disease control. 2008 a b 2009 Application timing Proper timing of preventive applications is necessary to maximize the residual effectiveness of the fungicide and target a vulnerable portion of the pathogen's life cycle. Because preventive applications are made before plant symptoms are evident, environmental cues, such as soil tempera- ture, have been used as indicators of application timing for control of soil-borne turf pathogens. In this field study, we were not able to statistically determine the most effective soil temperature threshold for fairy ring prevention. A weak data trend suggests that preventive applications made at five-day soil temperature averages of 55 F or 60 F (13 C or 16 C) may be most effective, but further study should be conducted to confirm this result. Surfactant tank-mix and irrigation timing Fungicide application methods may affect the a c c c c b b b b a efficacy and duration of preventive control. Other surfactant chemistries may respond differently, but data in this research suggest that tank-mixing a surfactant with a preventive fungicide does not increase disease control and may result in slight phytotoxicity. In a curative situation, however, fungicides must be tank-mixed with a surfactant to aid delivery of the material through the hydro- phobic layer and into the target zone of the soil profile. Because hydrophobicity is not present in a preventive situation, the surfactant may diminish the soil residual of the fungicide and, therefore, reduce its efficacy. Results of this study also indicate that the impact of watering-in the preventive DMI appli- cations immediately versus 10 hours later is neg- ligible. Superintendents should therefore be able to wait until the night irrigation cycle to water-in the fungicide if play is a concern. This statement comes with a degree of caution, however, as inad- equate control has been reported by superinten- dents if the fungicide is not watered-in within a 10- to 12-hour time frame. 80 GCM December 2012 2009 Discussion This study demonstrates the efficacy of using certain DMI fungicides for preventive fairy ring control, thereby reducing the need for more numerous and costly curative fungicide applica- tions and soil remediation procedures. No differ- ences in field efficacy were detected among the DMI fungicides tested in this study; however, two spring applications on a 28-day interval tend to provide longer residual control under high disease pressure than a single application. AUDPC AUDPC

Articles in this issue

Archives of this issue

view archives of Golf Course Management - DEC 2012