written by Lee Miller and Dr. Lane Tredway
Recent research by the NCSU Turf Pathology Team has shown that spring is the best time to control fairy rings. Two spring applications of Bayleton (1 oz product/1,000 sq ft) on a 28 day interval have been shown to effectively prevent fairy ring symptoms from occurring on putting greens during the summer. These preventive treatment are most effective when 5-day average soil temperatures are between 55°F and 65°F, which was in late March last year. Soil temperatures in Raleigh, NC have recently entered this range, with Charlotte and coastal regions a few degrees ahead and western NC quite a few degrees behind. Forecasts indicate a warm-up going into this weekend, which should push all but the mountain courses into the preventive application window.
For best results, these applications must be immediately watered-in with 0.2 - 0.25" of irrigation to deliver the fungicide into the thatch and soil profile. Tank-mixing surfactants or wetting agents with this preventive application does not increase fungicide efficacy. However, wetting agents should be used on a normal schedule as soil moisture conditions warrant and along with curative fungicide applications. Other DMI or QoI fungicides may also be effective in this preventive strategy, and are being evaluated.