Recurring Nuisance Fairy Rings October 10, 2011 By Todd Lowe

Mycelial strands and small fruiting structures from a fairy ring fungus. 

Fairy rings can occur on golf courses at any time in our region, but are especially problematic during rainy summer months.  Fairy rings are created by different types of fungi that inhabit soil and feed on organic matter.  Green Type II rings occur as the fungi break down lignin in organic matter and release nitrogen for turf uptake.  Detrimental Type I rings occur if the infected areas become hydrophobic from substances that coat sand particles, where the fungus resides.

There are several fairy ring types, but large damaging Type I rings have been observed on several golf courses over the past month.  This past month has also seen above-average rainfall that has encouraged fairy ring development and recurrence.  A soil sample from a recent TAS visit revealed a mass of white strands and attached objects that resembled small cotton balls.  Dr. Mike Fidanza of Penn State University identified them as mycelial strands with small fruiting structures.  Other signs that sometimes accompany fairy rings include orange coloration within the organic matter and a strong mushroom odor.

Fairy rings are often managed with the fungicide Prostar (flutolanil), but other fungicides have been successful at times.  It is important that fungicides be watered into the soil where the fungus resides, so that it contacts the organism.  Green, Type II rings can be masked with supplemental fertility, but aggressive Type I rings may require additional aeration to infected areas followed by wetting agent applications.  To learn more about fairy ring biology and control, read Dr. Fidanza’s article /content/dam/usga/pdf/imported/course-care/090308.pdf.

It is important to remember that fairy rings can be only managed, not eradicated.  Fungicides and wetting agents are effective tools to suppress symptoms, but a change in weather will significantly improve conditions and dissuade fairy ring recurrence.  Drier, cooler conditions have already occurred over the past week and will continue over the next few months.  This should provide excellent turf recovery and reduce future fairy ring issues.

Source:  Todd Lowe, or 941-828-2625