Written by Dr. Lee Miller and Dr. Lane Tredway
Two preventive applications of Bayleton (1 oz product/1000 ft2) or Tourney (0.28 oz product/1000 ft2) on a 28-day interval have been shown to effectively prevent fairy ring symptoms from occurring on putting greens during the summer. The initial preventive application should be made when soil temperatures average 60° F consistently, which was in late March in Raleigh last year. It has been a mild spring and soil temperatures in most of NC have not reached this level yet. A forecasted weekend warm-up may push soil temperatures in southern regions like Charlotte and Wilmington into this window. Next week should be a good target for the initial application in these southern areas, however, Raleigh and points north should wait for the next temperature spike.
For best results, these applications must be watered-in with 0.2 - 0.25" of irrigation to deliver the fungicide into the thatch and soil profile. It is preferable to immediately water-in the application, but at the least the application should be watered-in that night. Do not tank-mix wetting agents with these preventive applications as it has been shown to reduce control. However, wetting agents should be used on a normal schedule as soil moisture conditions warrant and along with curative fungicide applications.