Influence of fungicide timing and post application irrigation on dollar spot severity
J. E. KAMINSKI (1), J. Inguagiato (2), A. I. Putman (3)
(1) The Pennsylvania State University, University Park, PA, U.S.A.; (2) University of Connecticut, Storrs, CT, U.S.A.; (3) North Carolina State University, Raleigh, NC, U.S.A.
Phytopathology 101:S87

Dollar spot, caused by the pathogen Sclerotinia homoeocarpa F.T. Bennett, is a common disease of golf course turf. Our study was conducted to compare early versus traditional preventive applications of different fungicides and the influence of post application irrigation on disease suppression. A total of seven evaluations were conducted between 2008 and 2010 in Connecticut and Pennsylvania. All studies were designed as a 2 × 2 × 4 factorial and arranged as a randomized complete block with 4 replications. The main treatments included timing (mid-April or mid to late May), irrigation (none or 2.5 mm), and fungicide (none, propiconazole, boscalid or vinclozolin). All treatments decreased dollar spot when compared to the untreated control plots, but few differences were observed among the main effects. Of 50 rating dates assessed across all studies, dollar spot was reduced on only 5 and 4 dates in plots treated at early or traditional timings, respectively. Irrigation was only significant on 3 of 50 rating dates and in all cases, the application of post application irrigation resulted in an increase in dollar spot severity when compared to plots receiving no irrigation after application. Results of this study indicate that while early season fungicide applications may suppress dollar spot infection centers, they may offer little benefit over properly timed preventive fungicide applications.