We evaluated fungicide treatments for disease control at the William H. Daniel Turfgrass Research and Diagnostic Center at Purdue University in West Lafayette, Indiana. We conducted green trials on creeping bentgrass ‘Crenshaw’ and ‘Pennlinks’ greens.
Figure 1: Crenshaw bentgrass fungicide treatment. Final applications were submitted on August 30 for Maxtima and Traction and August 23 for Xzemplar. The arrows indicate application periods of 14 days (Xzemlar) and 21 days (Maxtima and Traction) for each fungicide.
From April 1 to September 29, 2023, we will mow both greens five times a week at 0.135 inches. We used 4 fl. Wetting agent Excalibur (Aqua-Aid Solutions) on both greens on June 9 and 28. oz/1000 sq. ft. price on July 20 was 2.7 fl oz. oz/1000 sq. ft. to limit localized dry spots.
We then applied Fleet wetting agent (2.7 fl oz/1000 sq ft) to the greens on August 16th to limit localized dry spots.
We used 9 Tempo SC fluids (cyfluthrin, Envu). oz/acre and Meridian (Thiamethoxam, Syngenta) 12 fl oz. June 9 oz/acre for ant control. We applied 0.5 lb of nitrogen fertilizer on June 10 and September 2 using Country Club MD (18-3-18, Lebanon Lawn). N/1000 square feet
Our experimental plots were 5 x 5 feet in size and were designed using a randomized complete block design with four replications. Use a CO2 powered sprayer at 50 psi and three TeeJet 8008 flat spray nozzles at the equivalent of 2 gallons/1000 square feet of water.
In both studies (Experiment 1 and Experiment 2), we began all treatments on May 17, with the timing of the last administration varying across treatments (Table 1). On July 1, we used a hand spreader to evenly distribute dollar spot infested rye grain at a rate of 12.5 cc per bed. We then leave the rye grain on the surface of the lawn for four days before mowing.
We assessed the severity of dollar spots based on the number of infection centers at a site. The area under the disease progression curve (AUDPC) was calculated using the trapezoidal method using the formula Σ [(yi + yi+1)/2] [ti+1 − ti], where i = 1,2,3, … n -1, where yi – rating, ti – time of the i-th rating. Data were subjected to analysis of variance and mean separation (P=0.05) using Fisher’s protected LSD test.
We first observed differences in dollar spot control between treatment sites on May 31st. On June 13, dollar spot severity in the project treatments was significantly higher than in other treatments (Figure 1). Conversely, the $20 July 20 program’s spot severity was lower than other treatments.
On August 2, the areas were treated with 1.3 fl of Traction (fluazimide, tebuconazole, Nupharm). oz/1000 sq. ft. – The 21-day spot price in US dollars was significantly higher than for parcels treated with Maxtima (fluconazole, BASF) 0.4 oz. oz/1000 sq. feet over the same period. On September 16 and 28, two and four weeks after final application, respectively, plots treated with Traction had significantly more spot dollars than Maxtima and had significantly lower AUDPC values than control.
We first saw the dollar spot on July 7th. As of July 7, all treated sites had less than one outbreak per site. There were no treatment differences throughout the experiment. AUDPC values in all treated plots were significantly lower than those in untreated control plots (Table 1).
Purdue University’s Daniel Turfgrass Research and Diagnostic Center evaluated the effectiveness of fungicide treatments on mature, free-standing creeping bentgrass.
From April 1 to October 1, mow three times a week to a height of 0.5 inches. We introduced Ference (cyantraniliprole, Syngenta) on June 30 at 0.37 fl. oz/1000 sq. ft. for white grub control. On July 20, we used the moisturizing agent Excalibur at a dosage of 2.7 fl. oz/1000 sq. ft. to limit localized dry spots.
We used Fleet moisturizing agent (Harrell’s) on August 16th in a 3 fl. oz/1000 sq. ft. to limit localized dry spots. We then applied 0.75 lbs of nitrogen on May 24 using Shaw (24-0-22). N/1000 sq. ft. Sep 13, 1.0 lbs. N/1000 square feet
Plots were 5 x 5 feet in size and arranged in randomized complete blocks with four replicates. Use a CO2 powered sprayer at 45 psi and three TeeJet 8008 flat spray nozzles at the equivalent of 1 gallon/1000 square feet of water.
We applied the first fungicide application on May 19th and the last on August 18th. Rye grain infected with the dollar spot pathogen was evenly applied by hand spreader on June 27 and July 1 at the rate of 11 cm3 and 12 cm3 per plot, respectively. We then leave the rye grain on the surface of the lawn for four days before mowing.
Disease severity was assessed every two weeks throughout the study. Disease severity was assessed by visually assessing the percentage of affected area at each site. The area under the disease pressure curve (AUDPC) was calculated using the trapezoidal method described above. Data were subjected to analysis of variance and mean separation (P=0.05) using Fisher’s protected LSD test.
We first observed dollar spots (<0.3% severity, 0.2 infected lesions per site) on June 1, and their numbers increased following inoculation. On July 20, the areas were treated with Encartis (boscalid and chlorothalonil, BASF) 3 fl. oz/1000 sq. ft – 14 days and 4 fl oz/1000 sq. ft. – 28 days, Daconil Ultrex (chlorothalonil, Syngenta) 2.8 fl oz/1000 sq. ft. – 14 days, programmed treated plots had fewer dollar spots than all other treated plots and untreated controls.
From July 20 to September 15, all treated plots had fewer infestations than untreated control plots. Areas treated with Encartis (3 fl oz/1000 sq ft – 14 days), Encartis (3.5 fl oz/1000 sq ft – 21 days) September 2, two weeks after final application (WFFA) d), Xzemplar (fluxapyroxad, BASF) 0.21 fl. ounce/1000 sq. ft. – 21 days, Xzemlar (0.26 oz/1000 sq. ft. – 21 days) and program treated sites had the least dollar spot severity.
On August 3 and August 16, Encartis rates and application deadlines did not have a significant impact on US dollar spot controls. However, on September 2 and 15 (WFFA 2 and 4), sites were more likely to be treated with Encartis (3 fl oz/1000 sq ft – 14 days) and Encartis (3.5 fl oz/1000 sq ft). . . – 21 days) has lower USD stain resistance than Encartis (4 fl oz/1000 sq ft – 28 days).
In contrast, differences in the rate of administration and treatment timing of Xzemplar and Maxtima did not significantly affect the severity of dollar spots during the study period. Higher application rates of Daconil Action (3 fl oz/1000 sq ft) mixed with Secure Action did not result in a decrease in dollar spot. On September 2, Xzemplar’s Dollar Point infection control center treated fewer sites than Maxtima.
The AUDPC values of all treated sites were significantly lower than those of untreated control sites. Dollar spot severity was consistently lower in plots in this program throughout the study, with the lowest numerical AUDPC values of all treatments.
Sites treated with Daconil Ultrex alone had higher AUDPC values than sites treated with all treatments except those treated with 0.5 ml Secure (fluridinium, Syngenta). oz/1000 sq. ft. – 21 days) Daconil Action (2 fl oz/1000 sq ft) and Secure Action (azibendazole-S-methyl and fluazinam, Syngenta) 0.5 fl. oz/1000 sq. ft. – 21 days No phytotoxicity was observed throughout the study.
Post time: Apr-16-2024