Ask the expert: Five tips for dealing with fairy ring

You know fairy ring when you see it, but this complex disease manifests itself in a number of different forms—all of which can adversely affect golf course turfgrass.

Here are five fun facts and tips to help you identify and control a disease that is much more sinister than it sounds:

1. Fairy ring is caused by a group of soil-inhabiting fungi. The greatest concentration of fairy ring fungi reside in the thatch layer but can be found up to eight inches deep in the soil. This is important for preventive fungicide applications.

2. Dead turf within fairy rings (type I fairy ring) usually dies from drought stress. As fairy ring mycelium grows and concentrates, the soil becomes hydrophobic. Once death rings form, it is likely too late to treat with a fungicide. Instead, the hydrophobic layer should be physically disrupted. Soil surfactants and wetting agents will also help rehydrate the soil.
   

3. Dark green rings (type II fairy ring) are formed when fairy ring fungi degrade soil organic matter, releasing a boost of nitrogen to turf. This is an excellent time to treat with fungicides; several are labeled for control.
   

4. Toadstools and/or puffballs produced in fairy rings (type III fairy rings) should not be eaten; they are likely poisonous.
   

5. Fairy ring can successfully be treated preventively with DMI fungicides. Tourney Fungicide from Valent Professional Products, for example, is an excellent choice for fairy ring control. Target the first application when soil temperatures warm up to 55-60F at a two-inch depth for five consecutive days. Make a second application 21-28 days later. Applications must be watered-in immediately. Do not tank mix them with a soil surfactant or wetting agent, as this may drive the fungicide below where the fairy ring fungi are located.