Sponsored ResearchYou Can Use Ring 101 The curious, elusive, but troublesome fairy ring. BY MIKE FIDANZA, PH.D. he “fairy ring” has long been a subject of and legend dating back to pre-medieval T2,21 times. In fact, the largest single organism on earth is actually a fairy ring-type 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 , 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 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 ronment 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- 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 1 Arysta 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 2 Product 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. J. Schlossberg, and M. Franklin. 2007. Preliminary investigation of soil chemical is now offered by 3Tier Technologies and physical properties associated with type-I (Southlake, Texas), and similar kinds of fairy ring symptoms in turfgrass. Journal of products from Grigg Brothers (Albion, Hydrological Processes, 21(17):2285-2290. Idaho) and others are currently being 10. Fidanza, M. A., P. F. Colbaugh, M. C. tested. More information on those Engelke, S. D. Davis, and K. E. Kenworthy. 2005. Use of high-pressure injection to allevi- approaches to fairy ring control will ate type-I fairy ring symptoms in turfgrass. HortTechnology, 15:169-172. Type-II fairy ring symptoms are described as become available soon. stimulated plant growth as evidenced by circular 11. Gelernter, W., and L. J. Stowell. 2001. bands of dark green actively growing turfgrass. THE BOTTOM LINE Nitrogen in turfgrass health and stress. PACE Insights, 7(9):1-4. Sometimes these various treatment 12. Hallet, P. D., K. Ritz, and R. E. Wheatley. programs work, and sometimes they 2001. Microbial derived water repellency in on a 30-day interval, beginning in do not. What works to successfully golf course soil. International Turfgrass Society spring when fi ve-day average soil tem- manage fairy ring on one golf course Research Journal, 9:518-524. peratures reach 55°F, have provided may not work on another golf course, 13. Kostka, S. J. 2000. Amelioration of water season-long control in many cases.”20 repellency in highly managed soils and the or even at a different location on the enhancement of turfgrass performance through The same results can be expected on same golf course. After all, there are the systematic application of surfactants. tees and fairways. However, be mind- potentially more than 60 species of Journal of Hydrology, 231-232:359-368. ful of possible interactions between fungi that have been associated with 14. Rillig, M. C. 2005. A connection between DMI fungicides and plant growth fairy ring symptoms in turfgrass,5 and fungal hydrophobins and soil water repellency? Pedobiologia, 49(5):395-399. regulators. For curative control, again, these species likely vary in their sensi- 8,10,20 15. Roy, J. L., and W. B. McGill. 2001. Obser- refer to Table 1. tivity to fungicides. Although new vations on the chemistry of organic materials Questions are always asked about research results will provide a glimpse in water-repellent soils. International Turfgrass the use of soil modifi cation or soil into the elusive world of the fairy ring, Society Research Journal, 9:428-436. amendments and fairy ring. Realisti- there is still much to explore and 16. Salisbury, F. B., and C. W. Ross. 1985. cally, most golf courses have been on Plant physiology. Wadsworth Publ., Belmont, understand about fairy ring in turf. Calif. soil modifi cation programs using core Today’s turf manager does, however, 17. Schlossberg, M. J., A. S. McNitt, and aeration and topdressing with sand. have more good options to manage this M. A. Fidanza. 2005. Development of water Has this made the fairy ring probem problem than existed a few years ago. repellency in sand-based root-mixes. Inter- worse or better? It is hard to say. national Turfgrass Society Research Journal, Equally, the same could be said for soil 10:1123-1130. REFERENCES 18. Smiley, R. W., P. H. Dernoeden, and B. B. amendments. Results from the fi eld 1. Agrios, G. N. 1997. Plant pathology. Clarke. 2005. Compendium of Turfgrass have been variable where superinten- Academic Press, New York, N.Y. Diseases. APS Press, Minneapolis, Minn. dents have spot-treated or injected 2. Arora, D. 1986. Mushrooms demystifi ed. 19. Smith, M. L., J. N. Bruhn, and J. B. with inorganic soil amendments. Is the Ten Speed Press, Berkeley, Calif. Anderson. 1992. The fungus Armillaria bulbosa fairy ring being suppressed, or are the 3. Christians, N. E. 1998. Fundamentals of is among the largest and oldest living organisms. Nature, 356(6368):428-431. symptoms being masked? Again, it is turfgrass management. Sleeping Bear Press, Chelsea, Mich. 20. Tredway, L., and L. Miller. 2008. Breaking hard to say. Research is ongoing to the curse of putting green fairy rings. 4. Cisar, J. L., K. E. Williams, H. E. Vivas, and answer these questions about the way Carolinas Green: July-August 2008. J. J. Haydu. 2000. The occurrence and allevi- soil modifying products may or may ation by surfactants of soil water repellency on 21. Wollaston, W. H. 1807. On fairy rings. not affect fairy ring. Interestingly, in sand-based turfgrass systems. Journal of Phil. Trans. Roy. Soc. London, 2:133-138. rare occurrences, some superintendents Hydrology, 231-232:352-358. have dug out and physically removed 5. Couch, H. B. 1995. Diseases of turfgrass. MIKE FIDANZA, PH.D., associate professor, the fairy ring-affected area. This is a Kreiger Publishing, Malabar, Fla. Pennsylvania State University, Reading, disruptive, time-consuming, and messy 6. Fidanza, M. A. 2007. Characterization of Pa. For more information on fairy ring, soil properties associated with type-I fairy ring chore, and it’s questionable whether it symptoms in turfgrass. Biologia, 62(5):533- please contact Dr. Fidanza at maf100@ provides a long-term cure. It is hard to 536. psu.edu.

10 GREEN SECTION RECORD