Type I Fairy Rings

Fairy rings have appeared on golf course greens, fairways, and tees through much of Ohio. Earlier in the year the fairy rings were mostly cosmetic in appearance (dark green circles). However, under the current dry conditions fairy ring injury is most noticeable. These fairy rings are often classified as Type I rings, which exhibit a zone of dead grass, one or two zones of darker green stimulated grass and basidiocarps (photograph).

Generally speaking controlling fairy ring with fungicides may vary from excellent to marginal depending on the type of basiodiomycete (fungus). For example, Monica Elliot at the University of Florida had good success controlling the puffball fungus with flutolanil (Prostar®). Other fungicides that have shown efficacy on fairy ring include pyraclostrobin (Insignia®), and azoxystrobin (Heritage®). The use of a wetting agent may also limit the severity of fairy ring injury in the case where the circles become droughty. A Canadian study found that the organosilicone surfactants appear to work the best.

In a recently published study (Fidanza, et al., 2005), the researchers found that they could get acceptable Type I fairy ring control with flutolanil + Primer® applied via high-pressure injection. They also found that azoxystrobin applied alone via high-pressure injection gave excellent control.

It appears that flutlanil (Prostar®) or strobilin fungicide (azoyxtrobin (Heritage®) or pyraclostrobin (Insignia®)) applied with a wetting agent and either applied via high- pressure injection may be viable control methods. If high-pressure injection is not an option, research here has found coring prior to treatment then watering the above treatments in can provide a degree of control.

Reference

Fidanza, M.A., P.F. Colbaugh, M.C. Engelke, S.D. Davis, and K.E. Kenworthy. 2005. Use of high-pressure injection to alleviate Type-I fairy ring symptoms in turfgrass. HortTechnology 15(1): 169-172

Authors: Karl Danneberger