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Publication Type:
| Report |
Author(s): | Vincelli, P. C.;
Doney, Jack Jr.;
Powell, A. J. |
Author Affiliation: | Dept. of Plant Pathology, Dept. of Agronomy--University of Kentucky, Lexington, KY |
Title: | Control of dollar spot and brown patch of creeping bentgrass, 1991 |
Source: | Fungicide and Nematicide Tests. Vol. 47, 1992, p. 291. |
Publishing Information: | St. Paul, MN: American Phytopathological Society |
Keywords: | TIC Keywords: Agrostis stolonifera; Dollar spot; Lanzia; Moellerodiscus; Brown patch; Rhizoctonia solani; Disease control
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Abstract/Contents: | "A field trial was conducted to evaluate efficacies of various fungicidal products for control of dollar spot and brown patch of creeping bentgrass. The trial was conducted in a sward of creeping bentgrass (cv. Penncross) at the University of Kentucky Spindletop Research Farm in Lexington. The experimental area was fertilized with urea (46-0-0) at 1.0 lb N/1000 sq ft in Oct 90 and Mar 91. The area was mowed every 1-2 days to a height 0.25 in, and was irrigated as needed. Plots measuring 6 x 6 ft were established in a randomized complete block design (four reps) in an area that had not received applications of systemic fungicides in over 2 yr. The treatments indicated in the table were applied with a CO2-powered, hand-held sprayer fitted with LF-2-80 flat fan nozzles and delivering 3.5 gal/1000 ft2. Unless otherwise indicated, applications of all products were made at two-week intervals beginning 1 May 91 and continuing to 12 Jul. Neem oil, an oil that inhibits feeding activity of certain insect pests, has shown some activity in recent tests against certain fungal plant pathogens (Phytopathology 80:978). Margosan-0, a product that contains neem oil, was included in the trial to test for activity against dollar spot and brown patch. Severe outbreaks of dollar spot and brown patch occurred from natural inoculum during the treatment period. Dollar spot infection centers in each plot were counted on the dates indicated. Brown patch was assessed by visually estimating the percentage of plot are showing symptoms, using a scale of 0-25% at 5% increments and of 30-100T at 10% increments. Quality ratings were made on 19 Jul using a scale of 1 (poor quality) to 9 (excellent putting green quality). ASC-66825, Banner, Bayleton 25TO, Curalan F, Lynx 25DF, Sentinel, and Vorlan F provided excellent control of dollar spot at the rates tested. Control of dollar spot with Daconil 2787 was poor at the first assessment but was good at later assessments. Fungo 85DF failed to control dollar spot. Resistance to benzimidazole fungicides in fungi causing dollar spot was documented several years a ago at the site. Resistant strains apparently hav persisted in spite of not having used benzimidazole fungicides for at least 6 yr. ASC-66518 (3.8 oz only), ASC-66608, ASC-66825 (1.2 oz only), Banner, Daconil 2787, and Sentinel provided excellent control of brown patch on 3 Jul and 16 Jul. Lynx 25DF was not in the top statistical group at the 4 June brown patch rating; however, this rating was made only six days after the first application of Lynx 25DF (see footnote #3). No significant improvement in disease control was observed by adding X-77 spreader-sticker to Lynx 25DF. ASC-66791, Bayleton 25TO, and Fungo 85DF provided moderate control of brown patch. Curalan F and Vorlan F provided poor control of brown patch. Margosan-0 provided very poor control of dollar spot and no control of brown patch. To test for insecticidal active ingredient, a 1% solution of Margosan-0 was sprayed onto tobacco plants, and feeding behavior of apterae of Myzus persicae was monitored electronically (test performed by K.P. Srivastava, Visiting Scientist at UK). Neem oil has previously been efficacious on apterae but feeding was observed to be very active on these tobacco plants, indicating that the active ingredient(s) may not have been present at sufficient concentration in the lot of Margosan-0 used in these experiments. Plots treated with Sentinel consistently were observed to exhibit a slightly darker green color than other plots. Sentinel-treated plots also exhibited a slightly coarser texture when quality ratings were made. Plots treated with ASC-66608 exhibited a darker green color when disease assessments were made on 16 July but not at other dates." |
Language: | English |
References: | 0 |
Note: | Table |
| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete): Vincelli, P. C., J. Jr. Doney, and A. J. Powell. 1992. Control of dollar spot and brown patch of creeping bentgrass, 1991. Fungicide Nematicide Tests. 47:p. 291. |
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