PACE Turf - Turfgrass Information Center

Diseases

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

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.

Printable version of full report

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

 

Evaluation of Fungicides and Wetting Agents for the Management of Localized Dry Spot and Fairy Ring

Summary: In a replicated field trial conducted on a bentgrass (Pennlinks) practice putting green at Del Mar Country Club, Rancho Santa Fe, CA, the wetting agents Respond and Primer and the fungicides Heritage and ProStar were evaluated for their ability to control localized dry spot (LDS) and fairy ring caused by the fungus Agrocybe pediades. Key results included:

  • The fungus Agrocybe pediades, which produces small brown mushrooms, was identified from non-treated plots. This fungus is frequently associated with fairy ring symptoms in Southern California.
  • Two types of symptoms were detected in the plots: 1) Type B fairy ring symptoms: dark green circles of stimulated turf growth, with thatch degradation leading to low spots in the turf, and 2) Type C fairy ring (also frequently called localized dry spot) symptoms: dry spots with irregular areas of dead or dying turf and extreme hydrophobicity underneath.
  • Respond G and Primer significantly reduced the incidence of LDS (Type C fairy ring) symptoms. However these products applied by themselves had no effect on the incidence of Type B fairy ring symptoms.
  • Both Type B and Type C fairy ring symptoms were controlled best by monthly applications of ProStar (6 oz/1000 sq ft) plus the wetting agent Respond (3 oz/1000sq ft) (no posttreatment irrigation) and by monthly applications of Heritage (0.4 oz/1000 sq ft) plus the wetting agent Respond L (3 oz/1000 sq ft) (with post-treatment irrigation). Performing almost as well were monthly applications of Heritage (0.4 oz/1000sq ft), with or without post-treatment irrigation, and Heritage plus Respond (with no posttreatment irrigation).
  • It is important to note that while wetting agents can manage the symptoms of LDS (as can cultural practices such as verticutting, aerification, topdressing and hand watering), a fungicide such as ProStar or Heritage is necessary to kill the fungus that causes dry spot and fairy ring.
  • For reasons that are not clear, turf phytotoxicity occurred when monthly applications of ProStar (6 oz/1000 sq ft) were made without the addition of Respond L. This appears to be a unique observation, since ProStar is typically applied on golf courses, including Del Mar Country Club, under these same conditions with no negative results. We are working with AgrEvo to better understand this effect.

Printable version of full report

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

Cooperator: David Major, Del Mar Country Club

Sponsors: Mike Fidanza, AgrEvo, David Bower, UHS and Jim Petta, Zeneca

 

Evaluation of ProStar and ProStar Plus for Control of Fairy Ring on Golf Course

Summary: Both ProStar (6 oz/1000 square feet) and ProStar Plus (7.5 oz/1000 square feet) provided good to excellent curative control of fairy ring caused by Agrocybe pediades on a bentgrass green. A thirty day application interval resulted in control equal to that with a 15 day application interval. The addition of Bayleton to ProStar, in the form of ProStar Plus, did not improve the control offered by ProStar alone. In addition, ProStar Plus caused some reduction in turf quality. Applications were not followed by irrigation, a factor which may have aided in control.

Printable version of full report

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

Cooperator: David Major, Del Mar Country Club

Sponsor:  Dale Comer, AgrEvo

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