Fairy Ring Fungus

Symptoms, Causes, and Management

Symptoms

Fairy Rings appear in patches, rings, or arcs, starting at 1 foot or less in diameter but expanding yearly—sometimes reaching several hundred feet in old turf stands. The fungi responsible do not infect the grass but alter the soil environment, indirectly affecting or even killing the turf above. There are three types of Fairy Ring fungi:

🔹 Type I – Kills turf in patches, rings, or arcs due to hydrophobic (water-repellent) soil and thatch. It is most common in hot, dry summer weather.

🔹 Type II – Causes dark green, fast-growing rings or arcs due to nutrient release from fungal decomposition. Symptoms are most noticeable in nutrient-deficient turf.

🔹 Type III – Produces mushrooms or puffballs in a ring or arc, typically appearing after extended periods of wet weather.

💡 Symptoms may change throughout the year depending on weather conditions.

Development Factors

🪵 Some Fairy Ring fungi decompose organic materials like tree roots, stumps, waste lumber, or thatch, fueling their expansion. Established turf produces organic matter, which helps sustain these fungi.

🌱 Spore Dispersal:

• Fairy Ring fungi spread via wind, water, or lawn equipment.

• Type I rings are caused by hydrophobic residues left by fungi in the soil.

• Type II rings result from nutrient release, especially ammonium nitrogen, which may accumulate to toxic levels.

🛑 Conditions That Worsen Fairy Ring:

• Type I: Drought stress, poor irrigation, and infrequent aeration worsen symptoms.

• Type II: Nitrogen and iron deficiencies make symptoms more visible.

• Type III: Heavy rainfall, poor drainage, and over-irrigation encourage fungal growth.

Management Strategies

🛠 Preventative Cultural Practices:

• Remove large woody debris (stumps, dead roots, waste lumber) before laying sod or seeding turf.

• Reduce excessive thatch buildup through core aeration or dethatching.

• Maintain balanced soil moisture—avoid extremes of too wet or too dry.

• Ensure proper fertility—included in all Natural State Horticare lawn programs.

🚨 Drastic Measures such as soil fumigation, removing infested soil, or tilling may work temporarily, but Fairy Rings often reappear over time.

Management with Fungicides

Over 60 fungal species are linked to Fairy Ring, and their fungicide sensitivity varies. This makes site-specific treatment essential.

🛑 Fungicide applications are helpful but do not alter soil conditions. A key component to managing Fairy Ring is core Aeration, which addresses soil conditions directly.

🛠 Preventative fungicide programs like our Fungal Agronomic Program offer the best long-term control.

📢 A proactive, integrated approach—including cultural practices, soil amendments, and preventive fungicide use—is the best defense against Fairy Ring in turfgrass! 🌱✅