PACE Turf - Turfgrass Information Center

Evaluation of Proxy as a Growth Regulator and Seedhead Inhibitor on Overseeded Fairways

Summary: In replicated field trials conducted at two locations (The Country Club of Rancho Bernardo, and Admiral Baker Golf Course), the effect of the experimental product ethephon (Proxy) on turf quality, turf growth regulation and Poa annua seedhead inhibition was evaluated on bermudagrass fairways that had been overseeded with perennial ryegrass. Key results include:

  • The use of Proxy at rates of either 5 oz or 10 oz/1000 square feet resulted in a significant decrease in the density of Poa annua seedheads. This effect was observed for as long as seven weeks after a single application of Proxy.
  • Primo L (0.5 oz/1000 square feet) also resulted in decreased poa seedhead densities, but this effect was neither as strong nor as consistent as that for Proxy.
  • Overall, Proxy applications performed inconsistently in the regulation of cool season turf growth on overseeded bermudagrass fairways. While the 5-oz rate produced significant clipping weight reductions at one location, it took several weeks for the effect to appear. The 10-oz rate of Proxy resulted in significant increases in turf growth on several evaluation dates. This unexpected result was observed at both test locations.
  • No phytotoxicity was caused by any of the products tested, although Primo L (0.5 oz/1000 square feet) caused a dark colored cast to appear on treated plots due to growth inhibition and stress caused on senescing bermudagrass. The lack of any damage to bermudagrass or ryegrass caused by Proxy, in combination with its ability to reduce poa seedhead densities, may make it a valuable tool in golf course poa management on fairways and greens,despite its disappointing performance as a cool-season turf growth regulator.

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

Cooperators: Alan Andreasen and Mike Magnani, Admiral Baker Golf Course; Sandy Clark, The Country Club of Rancho Bernardo

Sponsor: Chris Olsen, Rhone-Poulenc

 

Evaluation of Chipco Proxy and EXP 310309 for Use as a Turf Growth Regulator on Kikuyugrass Fairways

Summary: In replicated field trials conducted on a kikuyugrass nursery that was mowed at fairway height, the effect of the experimental product ethephon (Proxy) or a combination of ethephon plus cyclanilide (EXP 310309) on turf quality, turf growth regulation and scalping was evaluated. Key results include:

  • A single application of Proxy at either 5 oz or 10 oz/1000 square feet had little or no effect on growth regulation of kikuyugrass, with significant clipping reductions observed on only one (5 oz rate) or two (10 oz rate) out of a total of six sampling dates. The addition of cyclanilide to ethephon, in the form of EXP 310309, had a small but positive effect on performance, with significant clipping reductions observed on two sampling dates (2.5 oz rate) or three sampling dates (5.0 ozrate). However, in contrast, Primo L (0.5 oz/1000 square feet) resulted in significantly reduced clipping rates on all six sampling dates.
  • Turf quality was not improved through application of Proxy or EXP310309 at any of the rates tested. In contrast, Primo L (0.5 oz/1000 square feet) produced turf with significantly improved quality (when compared to the non-treated check) on all six sampling dates.
  • The degree of scalping (appearance of brownish, stubbly, unisghtly areas, as a result of mowing) of kikuyugrass was not consistently reduced through application of either Proxy or EXP310309. In contrast, application of Primo L resulted in signficant reductions in scalping on all sampling dates.
  • In general, EXP310309 performed slightly better than Proxy in terms of growth regulation, turf quality and reduced scalping, suggesting that the addition of cyclanilide to ethephon has a beneficial effect. However, the improvement in performance was small, and still did not result in commercially acceptable performance. For these reasons, neither product was judged to demonstrate commercial viability for use as a growth regulator on kikuyugrass fairways.

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

Cooperator:  Bruce Duenow, La Jolla Country Club, La Jolla, CA.

Sponsor:  Chris Olsen, Rhone-Poulenc

Primo-treated Sod: Harvest, Establishment, and Transplant

Summary: Primo applied in combination with Sprint 330 to sod 48 hours prior to harvest provided consistently high quality turf and reduced clipping yields for two weeks following planting. The reduction in foliar growth prevented scalping of the newly planted turf during the first mowing when non-treated areas scalped. The benefit of reduced foliar growth is realized during establishment of newly sodded areas by prevention of damage caused by scalping and the ability to delay the first mowing. In addition to improved turfgrass quality by prevention of scalping, root length and root mass were equivalent in the Primo treated and non-treated areas.
In order to extend the reduced foliar growth advantage provided by pre-harvest Primo treatment beyond two weeks, the sodded areas need to be re-treated with Primo. Sod that was not treated prior to harvest but was later treated with Primo demonstrated reduced clipping yields but quality was slightly reduced compared to the non-treated and pre-harvest Primo treated areas. The optimum performance of sodded areas were the pre-harvest treated followed by a post-plant treatment four weeks after initial pre-harvest treatment. Primo improves early sod establishment by reducing the need to mow thereby preventing scalping problems that frequently occur during establishment of sod on new golf course greens. Moreover, turf quality and rooting are not reduced by the Primo treatments.

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Principal investigator: Larry Stowell, Ph.D.

Cooperators: Jeffery Beardsley, Big Canyon Country Club, Joe Foster, West Coast Turf, Nick Angelucci, Ciba-Geigy

Sponsor: Nick Angelucci, Ciba-Geigy

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