Joseph W. Rimelspach
Kerry Kline
Karl Danneberger
Michael Boehm
A curative red-thread fungicide study was initiated on a stand of Kentucky bluegrass (Poa pratensis) at the Tru Green/Chemlawn Research Center in Delaware, Ohio. The Kentucky bluegrass, consisting of 'Julia,' 'Merit,' 'Schamrock,' and 'Touchdown' at 25% each, was maintained at 2-inch height of cut. No fertilizer was applied in 1997. The soil is a Blount silt loam, with a pH of 6.2. The condition of the turf was good to fair. At time of treatment application, May 30, 1997, the temperature was in the high 70s with moderate soil moisture. The spring was cool and wet. Thatch was minimal. Spray treatments were applied with a hand-held CO2 pressurized sprayer with two 6503 nozzle tips, spaced 18 inches apart, at 40 psi, 2 gallons of water per 1,000 sq ft. Granular treatments were applied by hand. Plot size was 6 feet by 10 feet with each treatment replicated three times. The design of the experiment was a randomized complete block design. Percent red thread in each plot was determined on June 20, 21 days after application (21DAT), and July 7, 35 days after application (35DAT).
Many of the products gave substantial reduction of the disease and gave fairly long suppression. Fertilizer alone improved turf quality but did not significantly reduce disease activity.
| Treatments | Rate (oz/1,000 sq ft)** | % of Plot with Red Thread * | |
|---|---|---|---|
| 6/20 (21DAT) | 7/7 (35 DAT) | ||
| Heritage 40 WP | 0.2 | 0.0 | 0.0 |
| Heritage 40 WP | 0.4 | 3.3 | 0.0 |
| Bayleton 25 WDG | 1.0 | 3.3 | 0.0 |
| Chipco 26019 FL | 4.0 | 3.3 | 0.0 |
| Sentinel 40WG | 0.25 | 3.3 | 0.0 |
| Daconil Ultrex | 3.8 | 3.3 | 0.0 |
| Eagle 40WP | 1.2 | 10.0 | 6.7 |
| EXP10790B | 4.0 | 10.0 | 0.0 |
| Prostar 50WP | 2.0 | 10.0 | 0.0 |
| Procymidone 50WP | 1.0 | 10.0 | 0.0 |
| Daconil ZN | 6.0 | 13.3 | 3.3 |
| Fertilizer (20-5-10) | 1 lb N/M | 13.3 | 16.7 |
| Lynx 25DF | 0.75 | 16.7 | 0.0 |
| Chipco 26019 FL | 2.0 | 16.7 | 6.7 |
| EXP10790A | 4.0 | 20.0 | 20.0 |
| Daconil Weather Stick | 8.0 | 20.0 | 0.0 |
| Check (untreated) | -- | 20.0 | 23.3 |
| LSD (0.05) | 15.2 | 7.7 | |
| * The % disease was associated with a scale of 0 to 100, with 0 = no disease and 100 = to 100% of the plot being diseased. ** Ounces of product applied per 1,000 square feet. | |||