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| Web URL(s): | https://www.plantmanagementnetwork.org/pub/trial/fntests/reports/2006/T016.pdf
Last checked: 11/14/2016
Requires: PDF Reader |
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| Publication Type:
| Report |
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| Author(s): | Dernoeden, P. H.;
McDonald, S. J.;
Fu, J. |
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| Author Affiliation: | Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, Maryland |
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| Title: | Gray leaf spot control with azoxystrobin and propiconazole, 2005 |
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| Section: | Turfgrass
Other records with the "Turfgrass" Section
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| Source: | F&N Tests. Vol. 61, 2006, p. T016. |
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| Publishing Information: | St. Paul, MN: American Phytopathological Society |
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| # of Pages: | 3 |
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| Keywords: | TIC Keywords: Lolium perenne; Gray leaf spot; Disease control; Azoxystrobin; Propiconazole; Application rates; Application timing; Disease severity; Quality; Percent living ground cover
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| Cultivar Names: | Catalina II |
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| Abstract/Contents: | "Fungicides were applied with a CO2 pressurized (34 psi) sprayer equipped with a flat-fan (8010) nozzle, and calibrated to deliver 1.1 gal water per 1000 sq ft. Treatments were applied on the dates footnoted in the data table. Soil was a Keyport silt loam with a pH of 6.3 and 2.9% OM. 'Catalina II' perennial ryegrass was seeded on 3 May 05, and fertilized with 1.0 lb N/1000 sq ft on 16 May and 17 Jun. Turf was mowed twice weekly to a height of 2.5-in.. Plots were 5 ft x 5 ft, and were arranged in a randomized complete block with four replications. Percent of plot area blighted or diseased (i.e., brownish foliage) was assessed visually on a linear 0 to 100% scale where 0 = entire plot area green and healthy, and 100 = entire plot area brown or dead. Ratings exceeding 5% blighting were considered to be commercially unacceptable. Turf cover was rated visually on a 0 to 100 scale where 0 = entire plot area brown or dead and 100 = optimum density. Overall quality was rated on a 0 to 10 scale where 0 = entire plot area brown or dead; and 10 = optimum greenness and density. Data were subjected to analysis of variance (ANOVA) and significantly different means were separated according to Fisher's protected least significant difference t-test at P=0.05. The study site is known to contain P. grisea biotypes resistant to azoxystrobin. Gray leaf spot became active in the study area in early Aug, but did not progress beyond a low to moderate level. Fungicide applications were initiated 11 Jul, but due to a lack of disease activity treatments were suspended on either 1 Aug (21-day interval) or 8 Aug (14 and 28-day interval). Gray leaf spot development was erratic, with moderately severe disease levels being sustained between 19 Sep and 10 Oct. Thereafter, disease activity ceased and blighted plants made a rapid recovery. There were few notable or significant differences among fungicide treatments between 5 Aug and 5 Sep. During this period, all treated plots remained below the 5.0% blight threshold. Plots treated with Heritage and Heritage TL, however, had higher blight levels, when compared to Headway, Banner MAXX, Instrata or Daconil Ultrex-treated plots on 19 Aug. Gray leaf spot subsided the week of 5 Sep, but intensified again on 19 Sep and remained at a similar level until 10 Oct. On 19 Sep, plots treated with Headway (1.5 fl oz; 14-day interval = 14-d) and Banner MAXX had blight levels equivalent to the untreated control. All other treatments, except for possibly Heritage (0.4 oz; 28-d), had similar levels of disease. Plots treated with Heritage TL + Daconil Ultrex + Banner MAXX, however, were disease-free on 19 Sep. Disease pressure subsided by 30 Sep, but the same trends observed 19 Sep remained evident at this time. Disease pressure peaked on 10 Oct (63 days since most treatments were last applied). At this time, plots treated with Heritage (0.4 oz; 28-d = 70 days since last applied), Headway (both rates), Daconil Ultrex, and Banner MAXX had blight levels statistically equivalent to the untreated control. There were, however, few significant differences among fungicide treatments. Basically, Heritage TL (both rates), Heritage TL + Daconil Ultrex + Banner MAXX, and Instrata (both rates) provided better gray leaf spot control than Headway (1.5 fl oz; 14-d). Overall quality data indicated that only Heritage TL + Daconil Ultrex + Banner MAXX and Instrata (2.75 fl oz; 14-d) had improved quality significantly, when compared to the untreated control. Turf cover data collected after disease activity ceased revealed that blighting by P. grisea was mostly superficial in 2005, since fungicide-treated plots (92 - 97% cover) exhibited only 4 to 9% higher cover ratings, when compared to the untreated control (88% cover)." |
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| Language: | English |
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| References: | 0 |
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| Note: | Tables |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Dernoeden, P. H., S. J. McDonald, and J. Fu. 2006. Gray leaf spot control with azoxystrobin and propiconazole, 2005. F&N Tests. 61:p. T016. |
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| Web URL(s):
https://www.plantmanagementnetwork.org/pub/trial/fntests/reports/2006/T016.pdf
Last checked: 11/14/2016
Requires: PDF Reader |
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MSU catalog number: SB 951.3 .F82 |
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