M.L. Gleason, S.J. Helland, and J.P Newton
Department of Plant Pathology and Veenker Memorial Golf Course
Iowa State University
Trials were conducted at Veenker Memorial Golf Course in Ames, Iowa in 2002. Creeping bentgrass was maintained at 0.16-inch cutting height. Fungicides, selected for activity against brown patch, were applied using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal per 1,000 sq ft. The experimental design was a randomized complete block with four replications. All plots measured 4 ft x 5 ft. Because several treatments were added to the trial after it began, spray applications were initiated on 20 Jun, 28 Jun, and 21 Aug. These were followed by re-applications at recommended intervals until 11 Sep. Data were analyzed using the GLM procedure in SAS, and mean separations were determined using Fisher's protected LSD at P≤0.05.
Disease pressure was moderate to severe for Dollar Spot and Brown Patch. Most of the tested products suppressed both diseases significantly (P<0.05) in comparison to the unsprayed check. No phytotoxicity symptoms were observed during the trial.
| 26 Jun | 10 Jul | 2 Aug | 1 Sep | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Product and rate per 1,000 sq ft | Interval (days) | Brown Patchz | Dollar Spoty | Brown Patch | Dollar Spot | Brown Patch | Dollar Spot | Brown Patch | Dollar Spot |
| Unsprayed check | --- | 3.5 a | 16.7 a | 5.0 a | 34.2 a | 1.0 ab | 29.0 a | 3.4 a | 5.5 ab |
| Endorse WP 4 oz | 14 | 0.7 de | 11.7 ab | 0.0 d | 15.7 ab | 0.2 bc | 21.4 a | 0.4 f | 3.2 ab |
| Spectro 90WDG 4 oz | 14 | 2.5 a-c | 0.3 c | 0.0 d | 0.0 c | 0.0 c | 0.0 b | 1.0 c-f | 0.0 b |
| 3336 WP 4 oz | 14 | 0.5 de | 0.5 c | 0.0 d | 0.0 c | 0.0 c | 0.0 b | 0.1 f | 0.5 b |
| Spotrete F 4 oz | 14 | 3.2 a | 9.0 a-c | 5.0 a | 8.5 b | 1.5 a | 2.0 b | 3.2 a | 4.5 ab |
| 3336 WP 4 oz alt. w/ Spotrete F 4 oz | 7 | 1.0 c-e | 0.8 c | 4.7 a | 0.2 c | 0.0 c | 0.7 b | 1.7 b-e | 0.0 b |
| Chipco Signature 80WDG 1.5 fl oz, etcx | 14 | 0.0 e | 0.5 c | 0.0 d | 0.0 c | 0.0 c | 0.0 b | 0.0 f | 0.0 b |
| Magellan SC 4.1 fl oz + Daconil Ultrex 82.5WDG 2.1 oz | 14 | 1.5 b-e | 2.0 bc | 2.5 b | 4.0 b | 0.5 bc | 3.7 b | 1.6 b-e | 4.9 ab |
| Magellan SC 4.1 fl oz + Chipco 26GT 1.5 fl oz | 14 | 2.0 a-d | 3.4 bc | 1.2 c | 0.4 c | 0.0 c | 0.1 b | 1.0 c-f | 0.0 b |
| Magellan SC 4.1 fl oz + 3336 4 oz | 14 | 2.7 ab | 2.7 bc | 0.2 d | 0.0 c | 0.0 c | 0.0 b | 0.8 ef | 0.0 b |
| Magellan SC 4.1 fl oz + Mancozeb 75DG 4 oz | 14 | 1.5 b-e | 2.2 bc | 5.0 a | 6.5 b | 0.5 bc | 6.2 b | 2.1 b | 9.5 a |
| Eagle DG 8 lb | 14 | Xw | X | 4.3 a | 23.0 ab | 0.0 c | 7.0 b | 1.9 b-d | 0.0 b |
| DGPRO FVII 5.3 lb | 14 | X | X | 5.0 a | 11.3 b | 0.0 c | 5.0 b | 2.0 bc | 0.0 b |
| AG-400 8% v/v + Latron 0.2% v/v | 14 | X | X | X | X | 0.3 bc | X | 0.3 f | 2.2 ab |
| AG-400 4% v/v + Latron 0.2% v/v | 14 | X | X | X | X | 0.3 bc | X | 0.3 f | 3.5 ab |
| AG-500 8% v/v + Latron 0.2% v/v | 14 | X | X | X | X | 0.7 a-c | X | 0.7 ef | 8.5 a |
| AG-500 4% v/v + Latron 0.2% v/v | 14 | X | X | X | X | 0.3 bc | X | 0.3 f | 5.7 ab |
z Disease severity ratings on the following qualitative scale: 0 = no disease; 1 = 1-5%; 2 = 6-10%; 3 = 11-25%; 4 = 26-50%; 5 = >50% plot symptomatic.
y Percent plot symptomatic.
x Chipco Signature 80WDG + : (sequentially) Chipco 26GT2SC 4 fl oz; Triton 1.67SC 1 fl oz; Daconil Ultrex 82.5WDG 3.8 oz; Compass 50WG 0.15 oz; Triton 1.67SC 1 fl oz.
w Products were applied after this rating date.
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ISU Turfgrass:2003 Turfgrass Report | College of Agriculture |
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