Fairy Ring of lawn

Disease Information

Fairy Ring

 

Symptoms and damage

Fairy rings are caused by several species of fungi collectively referred to as basidiomycetes. They are soil- and thatch-borne fungi that form rings or arcs of dark green or dead grass. These rings can range in size from 2 inches to several yards in diameter. Fairy rings can be classified into three types. Type I fairy  rings have a band of dead grass and a band(s) of

dark green grass. Type II fairy rings lack the band of  dead grass, and Type III fairy rings consist of a ring of toadstools or puffballs that may be accompanied by a dark green ring. The lush green growth, called the zone of stimulation, is caused by the release of nutrients (primarily nitrogen) from the activity of the fungus decomposing organic matter in the soil, such as dead tree roots, buried construction material or excessive thatch. The ring of dead or dormant turfgrass plants, the zone of inhibition, is a result of the water-resistant (hydrophobic) properties of the fungal

mycelia. As the fungus grows in the thatch and soil, it prevents water from penetrating and reaching the plant roots. The result is plant dormancy or death. The majority of the fungal mycelia can be found below the fairy ring symptoms. As you move toward the center of the ring, the fungus is absent, resulting in a return to the normal appearance of the turfgrass plants and the characteristic ring symptom of this disease. The bands of lush growth often are visible throughout the growing season and may persist in the same location for many years as long as a food source remains.

COMMENTS on disease

Fairy ring damage is the most severe in dry, nutrientpoor areas and can be exacerbated by excess thatch.

Management

Chemical control

 Heritage (Azoxystrobin),

Insignia (pyraclostrobin) and (ProStar 70WP)

(flutolanyl).

Cultural methods

 Do not bury organic matter such as lumber and construction material, water and fertilize appropriately to mask symptoms, and balance rates of thatch accumulation and decomposition to decrease nutrients available to

the fungus. Fungicides and wetting agents may offer limited control. Soil replacement is also an option.

This can be quite labor-intensive and requires the removal of a 20-inch-wide by 8- to 30-inch-deep band of soil, followed by replacement with sterile soil and reseeding or sodding. Mushrooms and puffballs may

be raked up and discarded. Be sure to wear gloves if handling the fruiting structures to prevent skin contact with toxins such as alkaloids that are produced by some mushrooms and puffballs. Controlling weeds

in zones of dead and dormant grass also may be important.



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