Evaluation of Emerald fungicide programs for curative control of dollar spot in creeping bentgrass, 2006

摘要

Various fungicide programs employing Emerald 70WG were evaluated for their curative effects on dollar spot at the Lake Wheeler Turfgrass Field Laboratory in Raleigh, NC on ‘Dominant Plus’ creeping bentgrass maintained under putting green conditions.Mowing was performed five times weekly at a height of 0.220-in. with clippings collected, and thesite was irrigated to prevent drought stress. Fertilizer was applied as 7-23-19 on 16 Feb (0.3 lb N/1000 sq ft), 19-5-19 on 1 Mar (0.5 lb N/1000 sq ft), 20-5-10 on 19 Apr (0.75 lb N/1000 sq ft), 18-3-16 on 20 Mar, 5 May, and 21 Aug (0.5 lb N/1000sq ft), 20-20-20 on 20 Jul (0.125 lb N/1000 sq ft), and 18-3-6 on 6 Apr, and 12 Jul, and 4 Aug (0.24 lb N/1000 sq ft). Micronutrients were applied as Brexil Multi (3.0 oz/1000 sq ft) on 14 Feb, 27 Mar, 4 Aug, and HEP 35 (4.0 oz/1000 sq ft) on 6Apr and 29 Jun. Insect pests were suppressed with Allectus G (2.9 lb/1000 sq ft), Scimitar (8.0 fl oz/A), and Dursban Pro (1.5 fl oz/1000 sq ft) on 1 May, 11 Jul, and 24 Aug, respectively. Heritage 50WG (0.2 oz/1000 sq ft) and ProStar 70WP (1.6oz/1000 sq ft) were applied on 22 Jun and 10 Jul respectively for control of brown patch in the experiment. Plots were 3.33 ft x 6 ft and were arranged in a randomized complete block with four replications. Fungicides were applied in waterequivalent to 2 gal per 1000 sq ft with a CO2-powered sprayer at 40 psi using TeeJet 8004 nozzles. All treatments were initiated on 19 Jun, and were reapplied as indicated in the table. Dollar spot incidence was assessed on 19 and 27 Jun, and 5,10, and 18 Jul by counting the number of dollar spot infection centers per plot. Data were subjected to analysis of variance and means separation by the Waller-Duncan k-ratio t-test (k=100).