Penn State News: Research Updates
Evaluation of a Copper-Plated Roller for Dollar Spot Management By Michael Fidanza, Ph.D., Professor of Plant and Soil Science
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ollar spot (Clarireedia jacksonii, formerly Sclerotinia homoeocarpa) is a major disease of golf course fairways in the Mid-Atlantic USA region. In addition to proper cultural practices and a responsible fungicide program, rolling the turf has a beneficial effect at reducing the incidence and severity of dollar spot. This field trial was conducted in 2018 on fairway-height ‘PennTrio’ creeping bentgrass at the Center for the Agricultural Sciences and a Sustainable Environment (Penn State Berks Campus, Reading, PA). The rootzone is 100% sand with pH 7.3 and 0.31% organic matter. Individual plot size was 3 × 5-ft and all plots were arranged in a randomized complete block design with four replications. Fungicides were applied every 21 days to attempt to “stretch” the application interval. Some plots received a rolling treatment from a new and unique, copper-plated metal roller measuring 4-in. diameter × 27-in. length and weighing 340 lbs. Dollar spot first appeared in early June.
KEY RESULTS: • Plots that received only the rolling treatment had a noticeable reduction in dollar spot compared to untreated plots. • Plots that received fungicides only at the lower label rate and extended 21-day interval, or those plots that received fungicides with the weekly rolling, also had a noticeable reduction in dollar spot compared to untreated plots.
Bert Brace testing the copper-plated roller.
Average number of dollar spot infection centers per plot for each treatment from June 6 to August 1, 2018. Untreated = check plot; DA = Daconil Action 6.1SC (contact site of activity), 2 fl oz/1000 ft2; X = Xzemplar 2.47SC (acropetal penetrant site of activity), 0.21 oz/1000 ft2. R = Rolling one time/week. Fungicides applied in 1 gal water-carrier per 1000 sq ft at 21-day intervals on May 23, June 13, and July 25. Rolling conducted once per week from May 21 through August 1, two passes (up-and-back) per rolled plot. Source: Plant Disease Management Reports (www.apsnet.org).
Soil Amendment by Ca- and Mg-Silicates and Perennial Ryegrass Wear Resistance By Derek Pruyne, MS Agronomy ’14; Max Schlossberg, Assoc. Prof. Turfgrass Nutrition; and Wakar Uddin, Prof. Turfgrass Pathology; Center for Turfgrass Science, Pennsylvania State Univ.
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hile not recognized as a plant essential nutrient, silicon (Si) accumulates in epidermal and vascular tissue of grasses. A field study of ‘CrossOver’ Ca/ Mg-silicate (SiO3) pelletized soil conditioner/liming agent (Harsco Minerals Intl., Sarver, PA) was conducted on a neutral perennial ryegrass field within the J. Valentine Turfgrass Research Center (University Park, PA). Plots were trafficked weekly by a dedicated wear simulator, June through Sept. Multispectral radiometric canopy quality measures, clipping yield, clipping/tissue composition, soil pH, and plant-available soil Si levels from the 0–3" and 3–6" depths were regularly collected over the two-year study. Similar multiyear field
16 Pennsylvania Turfgrass • Winter 2020
experiments, employing identical products and methods on creeping bentgrass fairways and putting greens, were inconclusive. However, perennial ryegrass plots under intense wear/ traffic and treated annually by granular application of Ca/ Mg-silicates at 25 or 50 lbs per 1000 ft2, showed significantly improved mean canopy quality relative to adjacent plots receiving equal Ca and Mg as lime. This improved canopy density and color coincided with acetic-acid-extractable soil Si levels >70 ppm in the 0–3" soil depth. Further field trials are being initiated on perennial ryegrass and turf-type tall fescue to confirm these results and identify a critical leaf Si concentration for improved wear tolerance.
