Sponsored ResearchYou Can Use Fairy Ring 101 The curious, elusive, but troublesome fairy ring. BY MIKE FIDANZA, PH.D. he “fairy ring” has long been a subject of folklore and legend dating back to pre-medieval T2,21 times. In fact, the largest single organism on earth is actually a fairy ring-type fungus Armillaria sp., which Type-I fairy ring has been slowly growing and decom- symptoms are posing oak tree roots in a 37-acre site the most severe in northern Michigan for nearly 1,500 and are years, and this humongous fungus is associated estimated to weigh 21,000 pounds.19 In with necrotic turfgrass ecosystems, fairy ring symp- or dead turf. toms are described as a circle or ring of mushrooms, lush green circular or semi-circular bands of grass, or rings or arcs of necrotic or dead turf.5 The fungi that cause fairy ring symptoms in turf belong to the basidiomycete or mushroom group, the surfaces of sand and soil particles, A COMMON PROBLEM and these fungi grow and colonize the contributing to the development of In the past, fairy ring symptoms may soil, rootzone, and thatch.18 In nature, hydrophobicity or soil water repellency have been dismissed as a curiosity with these fairy ring fungi are known as in the rootzone.9,12,14,15,17 With type-I minimal impact on the turf surface or wood-decayers, which means they fairy ring, the loss of turf and stand interference with the game of golf. enjoy a diet of lignin. Lignin provides density is due to the detrimental Higher nitrogen fertility rates, the use strength to plant cell walls, is common reduction in plant-available water in of maintenance products that contained in all higher plants,16 and is a major the soil, the inhibition of nitrogen and banned heavy metals (cadmium- component of turfgrass thatch.3 In fact, other nutrients, and the accumulation and mercury-based fungicides, for lignin is the second most abundant of ammonium to levels toxic to plant example), higher mowing heights, and organic compound on Earth after roots.6,7,9,11 Elevated concentrations of irrigation practices were very helpful cellulose, which is the major compo- ammonium and also sulfi des in the soil with masking fairy ring symptoms in nent of turfgrass leaf blades.3,16 This rootzone correspond to a lack of turf.5,18 Today, a reduction in fertility may explain why fairy ring symptoms bacterial activity needed to process practices, lower mowing heights, in- are often observed in turf near trees or those compounds due to the low soil creased use of sand for topdressing and in older native soil greens that contain moisture content and/or soil water in new construction, and irrigation buried tree stumps, other organic repellency conditions.9 It is an inter- practices (i.e., longer wet/dry cycles) debris, and composts. action of all these factors that causes all contribute to the persistent appear- Fairy ring-causing fungi do not the grass to suffer. So, a combined ance of fairy ring symptoms.7,9 A major directly infect turfgrasses like other knowledge of plant and soil sciences, concern is the development of soil pathogens such as Pythium sp. or biology, and plant pathology are water repellency and localized dry spot Rhizoctonia sp., but indirectly cause needed to understand the fairy ring conditions often associated with type-I turf damage by disrupting the envi- complex in turf and on your golf and type-II fairy ring symptoms, and ron ment below the surface.7 As the course. This knowledge can improve scalping on greens associated with fungus decomposes organic matter, its your control of this soil-borne, thatch- stimulated turf from type-II symp- mycelium and other substances coat borne problem. toms.4,6,7,9,13,14 Fairy ring symptoms are 8 GREEN SECTION RECORD commonly observed on new courses, WHAT TO DO? tant and a higher-than-usual water- newly rebuilt or renovated areas, and The unpredictable nature of fairy ring carrier volume.4,5,8,10,13 The extra water turf areas within one year after estab- and its destructive impact on turfgrass is important for coverage and to move lishment, but also on older and long- frustrate even the best golf course the fungicide into the target area below established areas.5,7,18 Fairy ring symp- superintendents. Some fungicide prod- the turf canopy.9,10 Spot aeration also toms in turf can be observed at any ucts are now available to treat fairy can help.5,8 Lee Miller, graduate student time of year, but they often occur ring symptoms. Table 1 details cur- at North Carolina State University during periods of hot/humid and rently labeled and soon-to-be-labeled (Raleigh, N.C.), under the guidance of dry weather, especially in turf that is products for fairy ring management. Dr. Lane Tredway, currently is investi- under-fertilized.7,18 Truly, the fairy This is a good reference list to keep gating fungicide application timing for ring family of organisms is incredibly handy. After all, with fairy rings being symptom reduction in greens.20 diverse and occurs over a wide range such a problem, it is not a question of An ideal fairy ring control program of environmental conditions. This is whether fairy rings will become a would start with aeration (i.e., needle- why the problem is so common here problem, but rather what to do when tine the affected area) to help vent in the U.S. and worldwide. The argu- you get them. excess ammonium, which can damage ment could be made that fairy rings In the research work done at Penn grass, but more importantly to promote are the most common problem affect- State, successful performance of those oxygen into the rootzone. Next, an ing golf turf worldwide, since these products applied in a preventive or application of a soil surfactant followed organisms are growing everywhere curative program may be improved by a fungicide (either sequentially or turfgrass is grown. with the combined use of a soil surfac- in a tank mix) in 100- to 150-gallon water-carrier per acre and then watered in, is essential for control. Do not under-water or over-water these Table 1 treatments, since one or two turns of List of fungicide products currently labeled for treatment of fairy ring symptoms in the USA. the irrigation heads or a light syringe Active Trade Name is helpful, if not essential, to move the Ingredient and Formulation Manufacturer1 Remarks2 material off the turf canopy and into Azoxystrobin Heritage 50WG Syngenta 0.4 oz., 28-day interval, the zone where the fairy ring organism 4 gal. water/1,000 sq. ft. is growing.5,8 Azoxystrobin Heritage TL Syngenta 2 fl . oz., 28-day interval, 4 gal. water/1,000 sq. ft. Be careful of those irrigation prac- tices during stress times that over-wet Azoxystrobin + Headway 1.39EC Syngenta 3 fl . oz., 28-day interval, Propiconazole 4 gal. water/1,000 sq. ft. or saturate the soil, as this can lead to 18 Fluoxastrobin Disarm 480SC Arysta 0.36 fl . oz., 28-day interval wet wilt. Equally, enough water Flutolanil Prostar 70WP Bayer Preventive: needs to be applied to avoid a hydro- 2.2 oz., 21-28-day interval phobic rootzone that is diffi cult to Curative: 4,13,17 4.5 oz., 30-day interval re-wet. Metconazole Tourney 50WDG Valent Label addition pending FAIRY RING RECURRENCE Polyoxin-D Endorse 2.5WP Cleary 4 oz., 2-3 applications, 7-day interval, minimum The recurrence of fairy ring symptoms 2 gal. water/1,000 sq. ft., on the same green or fairway year after include soil surfactant, irrigate 0.05 to 0.1 inch year may warrant a preventive or pro- Pyraclostrobin Insignia 20WG BASF 0.9 oz., 28-day interval active approach. Experience from the fi eld and research from North Carolina Tebuconazole Lynx 2SC Bayer Label pending State University suggests that spring Triadimefon Bayleton 50WP Bayer 1-2 oz., 14-day interval 2 oz., 21-day interval applications of triadimefon (Bayleton (Poa greens) 50WP) and tebuconazole (Lynx 2SC) (refer to label for preventive use instructions) can be helpful in preventing the onset of fairy ring symptoms.20 “The DMI 1Arysta LifeScience, Research Triangle Park, N.C.; BASF, Research Triangle Park, N.C.; Bayer fungicides triadimefon and tebucona- Environmental Science, Research Triangle Park, N.C.; Cleary Chemical Company, Dayton, N.J.; Syngenta Professional Products, Greensboro, N.C.; Valent USA Corp., Richardson, Texas. zole provide excellent preventative 2Product rate/1,000 sq. ft., application interval, and water carrier volume/1,000 sq. ft. as listed on the control of puff-ball fungi Lycoperdon product labels. Refer to product labels for specifi c information and instructions for product use. This perlatum and Vascellum pretense in golf list may not be inclusive of all commercially available products. course putting greens. Two applications MARCH-APRIL 2009 9 say. It does underscore just how frus- 7. Fidanza, M. 2007. New insight on fairy trating this problem can become. ring. Golf Course Management, 75(3):107-110. Using chemical controls may ultimately 8. Fidanza, M., F. Wong, B. Martin, and S. McDonald. 2007. Treating fairy ring with prove to be a better option than a sod fungicides, new soil surfactant. Golf Course cutter or a shovel. In addition to fungi- Management, 75(5):121-125. cides and soil surfactant strategies, a soil 9. Fidanza, M. A., J. L. Cisar, S. J. Kostka, J. S. nutrition approach to fairy ring control Gregos, M.