Nashawtuc battles fairy ring

Nashawtuc Country Club in Concord, Mass., now graces the land of literary giants with 6,729 yards of lush fairways, roughs and greens. It is the land of masters – masters of their craft such as Thoreau, Emerson and Alcott.

Master of his course, GCSAA certified superintendent Paul Miller works with the confidence and knowledge gained from 30 years spent nurturing and maintaining top-quality turf. Each year, his work is seen by thousands who watch the PGA Champions’ Fleet Boston Classic, which calls Nashawtuc Country Club home.

While Nashawtuc’s beauty may look effortless during the Classic, it isn’t. Miller and his maintenance team spend hundreds of hours a week caring for the course’s bentgrass and Poa annua greens. For the past six years, the greatest threat to the course has been a disease with a deceptively whimsical name: fairy ring.

“In order to keep a fast playing surface on the greens, we have to lean the grass down and keep it hungry and firm by controlling our water distribution, or eliminating it completely,” Miller says. “However, as we continue this drought stressing and leaning out, green circles and semicircles – fairy ring – will appear. Sometimes the grass dies causing unsightly brown circles, affecting putting speeds. As we continue to raise quality standards, this isn’t acceptable.”

Fairy ring is caused by mushroom fungi that live in the soil and thatch layer and has three types: Type I rings include a center section of dead grass surrounded by a ring of dark green grass; Type II rings have only a band of dark green turf, sometimes with mushrooms; Type III rings have only a ring of mushrooms.

“We can sometimes mask it with iron and low fertility, but if the area drought stresses and there is a brown patch or margin, there is little we can do,” Miller says. “The only successful approach is prevention. If we wait for the symptoms, we’re going to be in trouble.”

Miller tried many fungicides without success, including ProStar, Endorse, Bayleton and Heritage, as well as adding wetting agents to help transport the fungicide to the plant roots.

“I had 75 to 80 percent fairy ring control with ProStar,” he says, “but with high rates (4.5 ounces per 1000 square feet) it was expensive and I felt that I was overusing it.”

Working with his distributor and BASF, Miller decided to participate in a 2003 research program to test a new product.

“There are leaders and there are followers,” he says. “When no one else was doing this research and we were continually fighting the disease, I decided that we had to do something proactive.”

The new BASF fungicide, now registered as Insignia fungicide (active ingredient pyraclostrobin), is a strobilurin fungicide that works by inhibiting respiration in the fungi’s mitochondria.

The testing began on the 14th and 16th greens, where fairy ring was the most prevalent. On one half of each green, he used a Cushman Enviroject to inject Insignia into the turf at a rate of 0.9 ounces per 1000 square feet. On the other half, he topically sprayed the fungicide at the same rate but added Aquatrols’s wetting agent to help it reach the plants’ roots, where the fungus is active. On each green he left a six-foot check plot so he could see how active the product was in preventing fairy ring.

Miller applied the fungicide three times throughout the season, with the first application on May 5. Thirty days later, on June 4, he followed with a second application.

Insignia labels suggest 28-day application intervals for fairy ring, but with almost 100 percent control between the first two applications, Miller decided to test the fungicide’s length of control at the third application; On June 23 – 19 days after the second application – Miller applied the fungicide on the 14th green, but did not make an application on the 16th green. Instead, he waited 40 days, until July 14, to make the third application on the 16th green.

“I seemed to have the same results – almost complete control – even with an extended time between applications,” Miller says. “I was tickled with that, especially because Insignia is used at a much lower rate than ProStar.”

Also, there was no difference in control between the half of the green injected with Insignia and the half that was sprayed. Miller thinks that is partially due to the wetting agent.

“We’ve tried different methods and products. Without question, this was the best,” Miller says. “I think the key is the products and the timing, applying them before there is any activity – taking a preventive approach rather than trying to cure it. I also plan to build on this success by widening coverage and developing a rotation program that maximizes the fungicides without abusing them.”

Miller plans to continue to use Insignia, rotating it with ProStar, a member of the carboxamide family, to avoid resistance issues. He also plans to spray the product to provide broader control for other diseases like brown patch.