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First, thank you to Dr. Karl Danneberger for this opportunity to appear in Buckeye TurfNotes, and write about one of my favorite subjects - fairy ring. I have received many calls lately about type-I fairy ring symptoms on greens and fairways (International Centre for Fairy Ring Research - website coming soon). "Type-I" fairy ring symptoms are defined as necrotic, wilted, dead turf visible in a ring or circular pattern (Photograph 1 and 2). Last week, in Southeastern Pennsylvania, I measured a type-I fairy ring on a perennial ryegrass fairway. The semi-circular necrotic zone measured 32 feet in diameter. In 2005, that same ring measured 20 feet in diameter (Photograph 3). This active fairy ring has been expanding at a rate of 4 feet per year!

Figure 2. Intimidating type-I fairy ring directly in front of the pin on this green. What is the USGA ruling on this?

With spring, the rising soil temperatures combined with a prolonged lack of rain and "hungry" turf emerging from winter dormancy can reveal the visual appearance of fairy ring. At first, you may notice dark green rings of stimulated turf ("type-II" symptoms). However, be careful to observed the turfgrass along the margins of those rings, because that turf can quickly wilt and die ("type-I" symptoms). The underlying soil within the rootzone is often hydrophobic and difficult to re-wet by irrigation alone. Also, a detrimental accumulation of ammonium is often associated with fairy ring-affected soil. Therefore, turfgrass plants struggle to survive when their roots are dealing with drought stress and ammonium toxicity, which is an indirect result of the basidiomycete fungal organism that causes fairy ring.

Photograph 3. The diameter of this type-I fiary ring measured 20 feet in 2005 (recently measured 32 feet in diameter in 2008).

So, what can you do about active fairy ring now? A curative or "rescue" approach calls for a collaborative effort of aerification, fungicide, and a soil surfactant. First, aerify the affected area, but realize that some golfers may not appreciate this practice (Photograph 4). Aerification is important to help alleviate that harmful accumulation of ammonium, as well as facilitate the movement of fungicide and soil surfactant into the root zone where the basidiomycete fungus is active. Next, apply a fungicide plus soil surfactant tank-mix (4 gal water carrier per 1000 sq ft would be ideal). Water-in afterward if you have a native soil site, but careful with sand-based soil since excessive irrigation can "push" the materials through the target area. If you have the time and resources, another approach would be aerify first, then apply a soil surfactant, then irrigate thoroughly to wet the root zone. The next day, apply a fungicide (again, ideally in 4 gal water carrier per 1000 sq ft), and irrigate very briefly to move the fungicide off the turf canopy down into the rootzone.

Photograph 4.Type-I fairy ring on a creeping bentgrass/annual bluegrass green; notice the aerification holes - an important cultural practice to consider when battling fairy ring.

Prostar 70WP® was one of the first fungicides labeled for fairy ring control. Other fungicides now labeled for fairy ring control include Endorse 2.5WP®, Disarm 480WC®, Headway 1.39EC®, Heritage 50WG®, Heritage TL®, Insignia 20WG®, and Tourney 50WDG®. Both the Bayleton 50WP® and Prostar 70WP® have a preventive program outlined on their labels, and other fungicides are currently being tested. Many soil surfactants are available, and recent research has shown Revolution® to be an effective fungicide partner for fairy ring control. Other soil surfactants commonly used include Brilliance®, Cascade®, Dispatch®, Surfside®, Tricure®, and many others. Always refer to the fungicide and soil surfactant product labels for correct application rates. Also, a total plant nutrition approach to managing fairy ring is now offered by 3 Tier Technologies, which involves a program of nitrogen and fertility.

So, keep a watch-out for those pesky fairy rings, and have a great year in turf!

References:

Fidanza, M.A. 2007. New insight on fairy ring. Golf Course Management 75(3):133-136.

Fidanza, M, F. Wong, B. Martin, and S. McDonald. 2007. Treating fairy ring with fungicides, new soil surfactant. Golf Course Management. 75(5):121-125.

Fidanza, M.A., J.L. Cisar, S.J. Kostka, J.S. Gregos, M.J. Schlossberg, and M. Franklin. 2007. Preliminary investigation of soil chemical and physical properties associated with type-I fairy ring symptoms in turfgrass. Journal of Hydrological Processes 21(17):2285-2290.

About the Author

Mike Fidanza, Ph.D. is Associate Professor of Horticulture at ThePennsylvania State University Berks Campus. His responsibilities include teaching and conducting research in the area of turfgrass science and ecology.

Supplimental Information: Additional information on the fungicides mentioned can be found in the publication Families of Fungicides for Turfgrass

As a compliment to this posting, a Fairy Ring enhanced podcast is available.
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