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Fairy Rings1
M. L. Elliott and G. W. Simone2Fairy Rings
- Causal Agent(s): Chlorophyllum, Marasmius, Lepiota, Lycoperdon and other basidiomycete fungi
- Turfgrasses Affected: All warm-season turfgrasses.
- Occurrence: Fairy rings, especially the mushrooms, are most commonly observed during the summer months when Florida receives the majority of its rainfall. Fairy rings occur when large quantities of organic matter, such as lumber, tree stumps, logs, etc., are naturally located or have been buried in a turfgrass site. The fungi "feed" off this material. The mushrooms, which are all sizes and shapes, are the fruiting stages of these fungi.
- Symptoms/Signs: There are three types of fairy rings. Type I rings have a zone of dead grass just inside a zone of dark green grass. Type II rings have only a band of dark green turf, with or without mushrooms present in the band ( Plate 13 ). Type III rings do not exhibit a dead zone or a dark green zone, but simply have a ring of mushrooms present ( Plate 14 ).
CREDITS: M. L. Elliott
Plate 13. Type II fairy ring with dark ring of turfgrass and mushrooms.
CREDITS: M. L. Elliott
Plate 14. Type III fairy ring with only mushrooms present.
- Rings may be very small initially, less than 1 foot, but normally expand each year. It is not uncommon for rings to be 6 feet or more in diameter. The size and completeness (circular, semiquarter circles) of the bands varies considerably. Mushrooms will normally be produced during rainy weather. Since some of the mushrooms (ex.: Chlorophyllum spp. Plate 15 ) are poisonous, mushrooms should be removed or destroyed. Chopping them up with the mower is adequate.
CREDITS: M. L. Elliott
Plate 15. The mushroom of the poisonous fairy ring fungus Chlorophyllum.
- Cultural Controls: If necessary for aesthetic purposes, mask the dark green ring symptoms with nitrogen fertilizers. Although it is possible to excavate and fumigate the fairy ring sites, it is quite likely the rings will return if the food source for the fungi is still present underground. The rings will disappear naturally, but it may take up to five years.
- In some situations, the fungi will coat the soil particles to make the soil hydrophobic (repel water). This will result in rings of dead grass because the grass is being subjected to a very localized drought situation. If the soil under this dead grass is dry but the soil under healthy grass next to it is wet, then it will be necessary to break up the soil under the dead grass. A pitch fork is a good tool. Then apply a soil wetting agent and water the ring, and only the ring, daily to rewet the soil and encourage turfgrass recovery.
- Chemical Controls: azoxystrobin, flutolanil
- The fungicides inhibit the fungus only. They do not eliminate the dark green or dead rings of turfgrass, and they do not solve the dry soil problem.
- Refer to "Turfgrass Disease Management" section of the Florida Lawn Handbook" for explanations of cultural and chemical controls.
Footnotes
1. This document is SS-PLP-07, a series of the Plant Pathology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. This information is included in the Florida Lawn Handbook, SP-45. For a copy of this handbook, request information on its purchase at your county extension office. First published: May 1991. Revised: April 2001.2. M. L. Elliott, Associate Professor, Plant Pathology, Fort Lauderdale Research and Education Center, and G. W. Simone, Emeritus Professor, Plant Pathology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.
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U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
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