| Abstract/Contents: | "Fungicide programs were evaluated for maintenance of summer quality in creeping bentgrass putting greens. This trial was conducted at the Sandhills Research Station in Jackson Springs, NC on 'Dominant Plus' creeping bentgrass maintained under golf course putting green conditions. Mowing was performed five times weekly at a height of 0.156-in. with clippings collected. The site was irrigated as needed to prevent drought stress. Fertilizer was applied as 0-0-22 on 25 Mar (1.2 lb potassium/1,000 sq ft), 18-3-16 on 25 Apr and 30 May (1.4 and 0.6 lb nitrogen (N)/1,000 sq ft respectively), and 28-5-18 on 24 Jun, 14 Jul, and 12 Aug (0.16 lb N/1,000 sq ft each). Pelletized lime was applied on 18 Mar at 11.1 lb/1,000 sq ft. Harrell's MAX Calcium was applied on 24 Jun (7.4 oz/1,000 sq ft). Insect pests were suppressed with Topchoice Insecticide (87 lb/A), Sevin SL (5 qt/A) and Scimitar (10 fl oz/1,000 sq ft) on 27 Jun, 11 Jul, and 6 Aug, respectively. Oxadiazon 2G (100 lb/A) was applied on 12 Mar for pre-emergent weed control. Daconil Ultrex (1.8 oz/1,000 sq ft) was applied on 2 May to suppress an outbreak of dollar spot. Wetting agents were applied on 21 May (Magnus, 4 fl oz/1,000 sq ft), 11 Jul (Duplex, 0.5 fl oz/1,000 sq ft), and 6 Aug (Magnus + Duplex, 4 fl oz + 0.5 fl oz/1,000 sq ft). Plots were 3.33 ft x 6 ft and were arranged in a randomized complete block with four replications. Fungicides were applied in water equivalent to 2 gal per 1,000 sq ft with a CO2- powered sprayer at 40 psi using a TeeJet 9508E nozzle. All treatments were initiated on 20 May and were reapplied at the appropriate intervals as indicated in the table. Percent turf area exhibiting symptoms from a complex of brown patch and Pythium root rot activity were assessed on 29 Aug. Turfgrass quality was evaluated on 1, 15, 29 Jul, and 15 and 29 Aug, using a 1 to 9 scale (9=best, 5=acceptable) based on color, density, and uniformity. Data were subjected to analysis of variance and means separation by Waller-Duncan k-ratio t test (k=100). Turf quality in the untreated control declined steadily throughout July and August. No treatments separated statistically from the untreated control on 1 Jul and 15 Jul. On 29 Jul, the BASF Program, Luxembourg Program, Bayer Program #1, NCSU-EXP-13 + Chipco Signature 2008, and Phoenix Program #1 were providing acceptable turf quality that was significantly greater than the untreated control. On 15 Aug, 11 treatments improved turf quality compared to the untreated control, but only Phoenix Program #1 provided acceptable turf quality. By 29 Aug, 16 treatments improved turf quality in comparison to the untreated control, but none provided acceptable quality. Symptoms of brown patch and Pythium root rot occurred simultaneously on 29 Aug. The Luxembourg Program, Concert, Signature + Daconil Ultrex, QP Fosetyl-Al, and Aliette failed to provide significant suppression of this disease complex. Most other treatments maintained disease incidence at or below 5%." |
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