Effectiveness of fungicides on Bermuda grass infected with spring dead spot

Effectiveness of fungicides on Bermuda grass infected with spring dead spot

Spring dead spot is a fungal disease of bermudagrass and zysia grass. As the name suggests, it usually appears as circular patches of dead or dormant grass in the spring. Ophiospherella The prosecution. They are fungal pathogens that cause disease by infecting the roots and crowns of grass during the fall. These infections predispose the grass to winter injury.

Spring dead spot thrives in poorly drained or compacted soil with heavy straw. Cultural practices such as proper watering, fertilization and aeration can help prevent and manage the disease. Fungicides may be necessary in severe cases.

We conducted three fungicide efficacy studies at the Turfgrass Field Laboratory of North Carolina State University in Raleigh, North Carolina, on 'Champion' bermuda grass maintained as a golf course with a USGA-specification mix. Two trials focused on adipidine (Syngenta) Fungicide mixtures.

Adepidyn provides effective control of a wide range of plant diseases, including those caused by them Syndromes And Basidiomycetes mushrooms. It exhibits protective, curative and translational properties, meaning it can protect treated plant parts and penetrate plant tissue to combat existing infections.

We mowed the plots six times weekly at a rate of 0.15 inch, collecting the clippings. For each experiment, individual plots were 3 × 6 feet and were arranged in a randomized complete block design with four replicates.

We applied treatments in water equivalent to 2 gallons per 1,000 square feet for each trial using a CO2 sprayer with a single spray Tigit AI9508E nozzle at 50 psi.

Experiment 1

We applied the treatments on October 18 and November 8, 2018, and watered immediately with 0.2 inch of irrigation after application. We evaluated spring dead spot severity on April 16, May 7, and May 21, 2019, using a 281-intersection grid to identify the area within each plot with symptoms. The area under the curve (AUC) was calculated using the trapezoidal method with the formula ∑ ((yi + yi+1)/2)(ti+1 + ti), where i = 1,2,3,…,n- 1, where yi is the classification, and ti is the classification time i.

Spring dead spot intensity peaked at 26.8 percent on April 16 in untreated plots and more than 17 percent in untreated control through May 21 (Table 2). All treatments suppressed dead spot in the spring compared to the untreated control at each grading date. Plots treated with the intrinsic lexicon (BASF) and Velista (Syngenta) had AUDPC values ​​that were not statistically different from untreated control nomograms.

Table 2Experiment 2

In this trial, we applied the treatments on October 17 and November 22, 2019 and watered immediately with 0.2 inch of irrigation after application. We assessed vernal dead spot severity on March 27, April 28, and May 26, 2020 to visually estimate the percentage of symptomatic area within the plot. Data were subjected to analysis of variance and mean separation by Fisher's Protected LSD test (P = 0.05).

Spring dead spot intensity peaked at 37.4 percent on March 27 in the untreated plots and decreased to 26.1 percent in the untreated control through May 26 (Table 3). All treatments suppressed spring dead spot when compared to the untreated control at each grading date. On April 28 and May 26, plots were treated with Next Generations (Syngenta) at 0.24 fl oz. oz and 0.32 fl oz, A19649H at 0.32 fl oz, and Felista provided better spring dead spot suppression than the other two treatments.

Table 3Experiment 3

We began treatments for this trial on October 17 and reapplied on either November 9 or November 21, 2019. Fungicides were watered immediately with 0.2 inch of irrigation after application. We assessed spring dead spot severity on March 27, April 28, and May 26, 2020, to visually estimate the percentage of symptomatic area within the plot. Data were subjected to analysis of variance and mean separation by Fisher's protected LSD test (P = 0.05).

Spring dead spot intensity peaked at 25.9 percent on March 27 in the untreated plots, and decreased only to 21 percent in the untreated control by May 26 (Table 4). All treatments suppressed spring dead spot when compared to the untreated control at each grading date.

Table 4

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