Wetting Agents and Microbial Based Products for Control of Fairy Ring and Localized Dry Spot

March 15, 2005

Summary: A study was conducted to evaluate the efficacy of fungicides, wetting agents and biological control products, when applied curatively, for the management of fairy ring and localized dry spot. Results included:

• Symptoms of fairy ring that were observed during this trial included localized dry spot and the presence of puffballs (Bovista plumbea) and mushrooms (Agrocybe pediades). The presence of mushrooms or puffballs tended to occur in those plots where symptoms of localized dry spot were the most severe.
• The best performing products included Heritage plus Primer (with or without post-application irrigation), ProStar plus Primer, Nature Safe and Nature Safe plus Compete. These products all provided control that was commercially acceptable.
• Products that did not perform significantly better than the check included Heritage (without Primer), Nature Safe plus Yuccah Concentrate, Nature Safe plus Yuccah Concentrate plus Compete and Naiad.
• These findings indicate that the addition of Primer to fungicides such as Heritage and Prostar may be important for consistent performance, especially where symptoms of localized dry spot are severe. This confirms findings from PTRI fairy ring studies conducted in 1997, where the addition of Primer to Prostar resulted in significantly improved efficacy vs. Prostar alone. In addition, the results demonstrate that post-application irrigation does not appear to play an important role in the performance of Heritage.
• These findings also demonstrate that nitrogen fertilization (in the form of the organic fertilizer Nature Safe) is an important tool in alleviating the symptoms of fairy ring.
• In an interesting and unexpected twist, the addition of the wetting agent, Yuccah Concentrate, to Nature Safe fertilizer significantly decreased the efficacy the Nature Safe application. Similarly, the wetting agent Naiad did not provide good control of any of the fairy ring symptoms seen in this trial. This data indicates that although wetting agents are believed to be efficacious against fairy ring related dry spot symptoms, not all wetting agents perform equally. The reason for the disappointing performance of the wetting agents tested in this study is not clear.

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Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPPP, CPAg

Cooperator: Eric Lover, Dove Canyon Country Club

Sponsors: Aquatrols, Plant Health Care, Naiad, Zeneca