Roots in Research CMREC - Turfgrass Facility - Yield Year 2023

Maryland Extension Publications and Resources on Turf Grass

There is a compiled list of resources from the Maryland Department of Agriculture, Maryland Extension Publications, along with other resources and manuals to help support the turfgrass industry. The Turfgrass Technical Updates (TT-Bulletins) of the University of Maryland's Department of Natural Resource Science and Landscape Architecture are featured here. These are the most current versions of the publications.
Check out Maryland Turfgrass Council website for this list.

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Efficacy of Registered Fungicides for the Management of      Brown Patch

F. Shahoveisi and U. Kumar Thera, Depart. of Plant Sciences and Landscape Architecture, University of Maryland

A field study was conducted at the University of Maryland Turfgrass Research Facility, College Park, MD, to assess the efficacy of four registered fungicides for the management of brown patch on tall fescue cultivar ‘Bullseye,’ planted on native silt loam soil in 2021. The turfgrass was mowed twice weekly to maintain a height of 3 inches. Fungicides were applied at approximately 28-d intervals from 20 Jun to 17 Aug. Experimental plots were 3 ft by 6 ft and arranged in a randomized complete block design with four replications. For fungicide application, a CO2 backpack sprayer at 40 psi equipped with a single Teejet AI9508E nozzle was used to dispense fungicides in a water volume equivalent to 2 gallons per 1000 ft². Plots were fertilized with urea (46-0-0) at 0.9 lbs/1000 ft² rate on 27 Apr. For weed management, Dithiopyr L (0.36 fl oz/1000 ft2 on 11 Apr) and Sedgehammer (0.9 g/1000 ft2 on 13 Jul) were applied. Brown patch severity was visually assessed as the percentage of symptomatic area per plot biweekly between 10 Jul and 8 Sep. The area under the disease progress curve (AUDPC) was calculated using the following formula: Σ [[(yi+ yi+1)/2] [ti+1 - ti]], where yi and yi+1 represent disease rating at two consecutive dates, ti, and ti+1 represent the corresponding rating dates to yi and yi+1, respectively. Disease severity data were subjected to analysis of variance and means separation using Fisher’s least significant difference (LSD) procedure at α= 0.05.

The initial symptoms of brown patch were noted on 10 Jul, and the disease severity elevated as the study progressed. In the non-treated plots, disease severity reached its peak at 33.8% on 23 Aug and decreased to 5.3% by 8 Sep. All tested fungicides (Heritage, Armada, Pillar, and Fame) significantly reduced brown patch severity compared to the non-treated control across all rating dates. No statistical difference was noted among treated plots. The maximum disease pressure in treated plots ranged between 10.0 to 12.0% on 23 Aug. The AUDPC was also significantly higher for non-treated plots (1107.3) than treated plots, with a maximum AUDPC of 230.8.

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Efficacy of Preventative Fungicides for the Management of Brown Patch on Home Lawn Tall Fescue

F. Shahoveisi, T. Lai, Department of Plant Sciences and Landscape Architecture, University of Maryland

The efficacy of two experimental fungicides, three commercially available fungicides and an experimental biofungicide were assessed for brown patch control on tall fescue (‘Bullseye’) planted on native silt loam soil in 2021. The study was conducted at the University of Maryland Turfgrass Research Facility in College Park, Maryland. The turfgrass was mowed twice weekly to maintain a height of 3 inches. Depending on the treatment, fungicides were applied approximately every 14, 21, or 28 days from 22 Jun to 1 Sep. Experimental plots were 3 ft by 6 ft and arranged in a randomized complete block design with four replications. For the suspension concentrate (SC) formulations and biofungicide applications, a CO2 backpack sprayer at 40 psi equipped with a single Teejet AI9508E nozzle was used to dispense fungicides in a water volume equivalent to 2 gallons per 1000 ft². Granular formulations were dispersed evenly with a shaker bottle and irrigated with 0.1-inch water after each application. Plots were fertilized with urea (46-0-0) at 0.9 lbs/1000 ft² rate on 27 Apr. For weed management, Dithiopyr L (0.36 fl oz/1000 ft2 on 11 Apr) and Sedgehammer (0.9 g/1000 ft2 on 13 Jul) were applied. Brown patch severity was visually assessed as the percentage of symptomatic area per plot biweekly between 10 Jul and 8 Sep. The area under the disease progress curve (AUDPC) was calculated using the following formula: Σ [[(yi+ yi+1)/2] [ti+1 - ti]], where yi and yi+1 represent disease rating at two consecutive dates, ti, and ti+1 represent the corresponding rating dates to yi and yi+1, respectively. Disease severity data were subjected to analysiTs of variance and means separation using Fisher’s least significant difference (LSD) procedure at α= 0.05.

The initial symptoms of brown patch were noted on 10 Jul and the disease severity increased throughout the study until late August. Plots treated with Exp-UMD-BP-TF1 had significantly lower disease severity than the non-treated control on most rating dates except on 23 Aug. Plots treated with Exp-UMD-BP-TF2, Headway G, alternating Exp-PK-1 and Fame SC, and Fame SC alone had significantly lower disease severity than the non-treated control throughout the study period. Plots treated with Fame G had higher brown patch severity than all other treated plots on 25 Jul and the two August rating dates. Disease severity was lower in plots treated with Headway G, an alternation of Exp-PK-1 and Fame SC, and Fame SC alone compared to other treated plots during August rating dates. Brown patch AUDPC values in plots treated with Headway G, an alternation of PK-1 and Fame SC, and Fame SC were significantly lower than other treatments and the non-treated control. Further, AUDPC values of Fame G treated plots were not significantly different than the non-treated control. No phytotoxicity was observed during this trial.

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Evaluation of Fungicides for Managing Brown Patch on Creeping Bentgrass Fairway

F. Shahoveisi and K. Shah - Department of Plant Sciences and Landscape Architecture, University of Maryland

A study was conducted on 'Penncross' creeping bentgrass fairway at the University of Maryland Paint Branch Turfgrass Research Facility in College Park, MD, to evaluate the efficacy of registered fungicides in managing brown patch disease. The turfgrass was mowed three times weekly at a height of 0.5 in. Depending on treatments, fungicides were applied approximately every 14, 21, or 28 days from 8 Jun to 22 Sep. Individual plots, measuring 3 ft x 6 ft, were arranged in a randomized complete block design with four replications. All the treatments were applied preventively using a CO2-pressurized handheld sprayer equipped with a TeeJet air induction AI9504E nozzle calibrated to deliver water equivalent to 1 gal/1000 ft2 at 40 psi. No phytotoxicity was observed during the study period. Since brown patch did not occur naturally, plots were inoculated using rye and wheat seeds colonized with Rhizoctonia solani (10 cc per plot) on 15 Jun. Urea (46-0-0) was applied at the rate of 0.9 lb/1000 ft2 on 14 Apr and 0.5 lb/1000 ft2 on 7 Jul to promote disease development. Herbicide applications included Lesco Bentgrass Selective on 11 Apr, Dithiopyr L on 13 Apr and 5 Jul, and Sedgehammer on 2 Aug for weed management. Boscalid fungicide was preventatively sprayed at the label rate of 0.18 fl oz/1000 ft2 on 14 Jun, 29 Jun, 20 Jul, 2 Aug, and 15 Aug to control dollar spot. Brown patch severity was visually assessed as a percentage of plot area affected with disease between 10 Jul and 20 Sep. The area under the disease progress curve (AUDPC) was calculated to evaluate the seasonal progress of brown patch using the following equation: AUDPC = Σ([yi+yi+1]/2) (ti+1−ti), where yi and yi+1 represent disease rating at two consecutive dates, ti and ti+1 represent the corresponding rating dates, and n represents the number of days between the first and last rating dates. Data was subjected to analysis of variance and mean separation was performed using Fisher's least significant difference (LSD) at α= 0.05.

The initial symptoms appeared in the non-treated plots on 25 Jul. Throughout the observation period, the severity of the disease in non-treated plots increased notably, with a maximum severity of 42.5% by 8 Sep. This progression was significantly higher compared to the treated plots, as evidenced by the high AUDPC of 1022.4 in the non-treated control compared to treated plots with AUDPCs equal or lower than 72.0. Alternation of a higher rate of Tuque exoGEM with Secure Action provided the same results as individual applications of Tuque exoGEM where brown patch severity was 0.0% throughout the season. The alternation treatments of lower rate of Tuque exoGEM with Secure Action and Ascernity with Secure Action significantly reduced the disease compared to the non-treated control.

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