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| Publication Type:
| Report |
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| Author(s): | Vaiciunas, S. S.;
Majumdar, P. R.;
DiMarco, J. N.;
Tredway, L. P.;
Peacos, M.;
Clarke, B. B. |
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| Author Affiliation: | Department of Plant Pathology, Rutgers University, New Brunswick, NJ |
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| Title: | Curative control of gray leaf spot with selected fungicides, 1998 |
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| Source: | Fungicide and Nematicide Tests. Vol. 54, 1999, p. 522-523. |
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| Publishing Information: | St. Paul, MN: American Phytopathological Society |
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| # of Pages: | 2 |
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| Keywords: | TIC Keywords: Lolium perenne; Gray leaf spot; Pyricularia grisea; Disease control; Fungicide evaluation; Application rates; Application frequency; Disease severity; Tank mix
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| Cultivar Names: | Palmer II |
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| Abstract/Contents: | "Fungicides were evaluated for their ability to control gray leaf spot on perennial ryegrass at the Rutgers Turf Research Farm in North Brunswick, NJ. Turf was established 31 Jul 98 on a Norton loam with a pH of 6.4. The site was mowed at 2.0 in., two times per week, and clippings were not collected. Turf was irrigated to prevent drought stress. Seed was treated with Apron 50W (1.2 oz/1000 lb seed) on 16 Jul for preventive control of Pythium damping-off. Pythium blight was prevented with Subdue 2EC (2 fl oz/1000 sq ft) on 8 Sep. Fertilizer was applied as 16-4-8 on 9 Aug (1.0 lb N/1000 sq ft) and 10-10-10 on 8 Sep (0.5 lb N/1000 sq ft). Plots were 3 ft x 7 ft and were arranged in a randomized complete block design with four replications. Fungicides were applied in water equivalent to 2 gal per 1000 sq ft with a CO₂ powered sprayer at 30 psi using TeeJet 8003E nozzles. Treatments (trt) were initiated on 27 Aug, except 28 and 29, which were applied on a curative basis every 14 days beginning 10 Sep. Fungicides were reapplied at the appropriate intervals as indicated in the table. Turf was inoculated with a 5 ml conidial suspension of P. grisea per 21 sq ft plot (approx. 66,600 conidia per ml) on 22 Aug and 4 Sep. Percent turf area exhibiting foliar symptoms of gray leaf spot was assessed on 3 Sep, 14 Sep, and 9 Oct. Data were subjected to analysis of variance and means separation by Waller-Duncan k-ratio t-test (k=100). Gray leaf spot was first observed on 25 Aug, two days before fungicides were applied. The disease developed rapidly and was already severe (31% turf area infested on the untreated check, trt 38) by the first evaluation date on 3 Sep. Disease incidence continued to increase through 9 Oct. Overall, Spectro 90WDG (trt 1,2), CGA-279'202 50W (trt 7), Lynx 45W + Daconil Ultrex 82.5SDG (trt 10, 11), the 0.56 oz rate of Lynx 45 W (trt 16), Heritage 50WG + Daconil Ultrex 82.5SDG (trt 17-20), Heritage 50WG (trt 24-27), and Cleary 3336 50W (trt 32) provided good to excellent disease control throughout the study. Daconil Ultrex 82.5SDG (trt 21-23) did not provide adequate control of gray leaf spot, except the 7.6 oz rate on 9 Oct (trt 22), even though applications began only two days after symptoms were first observed. Although Heritage afforded good to excellent disease suppression when applied once (trt 24, 25) on 27 Aug, delaying applications until 10 Sep (repeated 24 Sep) resulted in poor disease control (trt 28, 29). S-4958 (trt 35 and 36) suppressed gray leaf spot 4 to 7 days post-treatment, but not 15 days after the final treatment on 24 Sep. Chipco 26GT 2SC (trt 34) and Prostar 70W (trt 33) did not provide acceptable control on any rating date. No phototoxicity was observed." |
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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):
Vaiciunas, S. S., P. R. Majumdar, J. N. DiMarco, L. P. Tredway, M. Peacos, and B. B. Clarke. 1999. Curative control of gray leaf spot with selected fungicides, 1998. Fungicide Nematicide Tests. 54:p. 522-523. |
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