Looking ahead for fairy ring

Spring has arrived and many golf course superintendents are preparing to face a familiar foe - fairy ring. Michael Fidanza, Ph.D. from Penn State and Lee Miller, Ph.D. from the University of Missouri share what they see coming and what to do about it.

What are you testing in the lab/field?

MF: I'm working in collaboration with Dr. Derek Settle (Chicago District Golf Association) and Dr. Henry Wetzel (Washington State University) on a USGA Green Section-sponsored fairy ring management study, to evaluate cultural and chemical methods in hopes of developing a "recipe" for an early curative fairy ring control program, and thus preventing the symptoms from developing into Type I (i.e., dead, necrotic turf). I am also evaluating fungicides (both commercially available and experimental) for fairy ring control in golf course turf. I am also collecting fairy ring species to maintain in the laboratory for growth studies and fungicide screening.

Looking ahead, what to you see 2012 looking like for the disease? Heavy? Light?

MF: I suspect, since we experienced a mild winter season, that a dry spring, perhaps, predisposes us to a hot and dry summer. We could see an increase in fairy ring symptoms. Again, with increased heat and drought stress, we're likely to see more fairy ring symptoms.

LM: No idea. In Missouri, we are coming off the third warmest winter ever and just had the warmest March in 110 years of record keeping. This past March broke the previous average temperature record by nearly 6 degrees, whereas past records were broken by ½ a degree here and half a degree there. In fact, the March temperature record would stand as the 10th warmest April ever. I don’t think anyone has a frame of reference to know where we stand with turf pests this season, and I would surmise that, without a significant April cool down, fairy ring outbreaks would occur early like everything else this year.

What are two or three strong tips for superintendents to either avoid or combat Fairy Ring?

LM: If applying a curative fairy ring control, you must remediate soil properties and control the fairy ring fungus. As Dr. Bruce Martin showed in previous research, applying fungicide with a wetting agent is absolutely necessary to achieve curative control. If applying a preventive fungicide application on a site with a history of the disease, spray the first application when soil temperatures consistently reach 55-60°F for five days, and the second application 28 days later. Low rates of the DMI fungicides Bayleton and the four T’s (Tourney, Torque, Triton, Trinity) have been shown to be most effective. Don’t tank-mix wetting agents but keep them on a normal spring schedule, preferably 14 days away from the fungicide application. Fungicide applications targeted for fairy ring or any soil borne disease must be watered-in with 1/8 - 1/4 inch of irrigation.

MF: Use at least 2 gallon water-carrier per 1,000 sq. ft. when making fungicide applications; 100 gallon water-carrier per acre (~2.3 gal water-carrier per 1,000 sq. ft.) is even better. When making fungicide and/or fungicide/soil surfactant applications to greens especially, but other turf areas areas as well, water-in immediately. Don't allow materials to dry on the turf surface or give the turf a chance to absorb the fungicide. The products need to get into the thatch/upper rootzone, where the fairy ring fungus is located.

How much water? Depends. Monitor the site, and put-on enough water to "rinse" the products into the thatch/upper rootzone. You'll know how much is enough by taking a soil probe and looking at the moisture content of the thatch/rootzone as the site is being watered.

I like using a soil surfactant to help combat hydrophobic soil conditions associated with fairy ring-affected turf sites. This water-repellent or hydrophobic condition is largely responsible for turf death; turf roots can take-up water in those harsh conditions, so the turf dies of drought stress. I also like using a soil surfactant to help minimize the severe wet/dry cycles or extremes in the soil rootzone, that is often assocated with fairy ring symptoms.

Also, monitor the site; with many products, a repeat application may be needed to really "knock-out" the fungus causing the fairy ring symptoms, and to help turf recovery.

Another good tip: Needle tine or "vent" the affected site. It's a good idea to do this before applying products. This helps to vent excess ammonium that can build-up in fairy ring-affected sites, helps with fungicides/surfactants getting to where they need to go into the thatch and upper rootzone, and helps speed turf recovery.