| Abstract/Contents: | "The experiment was conducted at the Valentine Turfgrass Research Center, University Park, PA, on colonial bentgrass maintained under golf course fairway management conditions, at 0.5 inch cutting height. The soil was Hagerstown silt loam with a soil pH of 6.4. The test area was fertilized on 27 May with 1.0 lb nitrogen (Scotts 19-26-5) per 1000 sq ft, and on 10 Jun with 1.0 lb nitrogen (Scotts 15-0-30) per 1000 sq ft, on 29 Jun with 1.0 lb nitrogen (Country Club 18-5-9) per 1000 sq ft. Treatment plots, 3 ft x 8 ft, were arranged in a randomized complete block design with three replications. Treatments were applied with a CO₂-powered boom sprayer, using TeeJet 8004 nozzles, at 40 psi, in water equivalent to 2 gal per 1000 sq ft. Applications were made on 2, 17, and 29 Jul, except as noted in the table. The experimental area was innoculated on 9 Jul, seven days after first treatment application, by hand-broadcasting Rhizoctonia solani-infested rye grains at a density of 20-30 grains per sq ft. The test area was covered with a woven greens cover to reduce radiational cooling on the evenings on 15, 16, 18, and 19 Jul. Disease severity was high during the latter part of July, but had declined to 38% (nectrotic turf area) in the untreated check plots by 4 Aug. Brown patch evaluated on 21, 24, 29 Jul, and on 4 Aug. Data were subjected to analysis of variance, and the mean were separated by Duncan's New Multiple Range Test (P=0.05). Daconil Ultrex and Spectro (8.0 oz) provided complete suppression of brown patch throughout the experiment. Eminent Spectro (4.0 oz), the tank mixtures of Chipco 26GT + 3336, Aliette Signature + Chipco 26GT, and Aliette Signature + Daconil Ultrex, as well as the preventive Heritage (0.2 oz) treatment, Fore, Compass, and Echo provided 95% or greater control of brown patch during the test period. By the 4 Aug evaluation, the curative treatments of Heritage (0.2 and 0.4 oz), and Chipco 26GT (2.0 and 4.0 oz) provided significant brown patch suppression from the 24 Jul application." |
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