Research Report
Spring Dead Spot Control Using Fungicides
different fungicides and rates applied in the trial.
Research results
Virginia Tech Researchers: Cam Shelton, Graduate Research Assistant, and David McCall, Ph.D., Research Associate Research Sponsors: BASF, FMC, PBI-Gordon and Syngenta
S
pring dead spot (SDS) is one of the most common diseases of bermudagrass in the transition zone. The pathogen causing SDS attacks the stolons and rhizomes of the bermudagrass plant, leaving depressed voids of turf as the turf breaks dormancy in the spring. To date, there is no silver bullet to consistently and completely control the disease in one growing season. Turf managers normally utilize various management strategies to reduce this disease to acceptable levels, including the use of fungicides. Product
Our research
Research trials were conducted at Tuscarora Country Club in Danville, VA, to determine fungicide efficacy against SDS. The research was conducted on a ‘MiniVerde’ ultradwarf bermudagrass practice putting green. Fungicides were applied when soil temperature declined to approximately 65°F (September 18, 2015), followed by a second application four weeks later (October 16, 2015). Treatments were applied at a spray volume of 2 gal./1,000 ft2 and immediately watered in. Table 1 shows the Application A (9/18/2015)
Rate
Application B (10/16/2015)
Untreated check
March 10, 2016
Lexicon
0.47 fl. oz./ 1,000 ft2
Velista
0.7 oz./1,000 ft2
Headway
3 fl. oz./1,000 ft2
Velista Headway
0.7 oz./1,000 ft2 3 fl. oz./1,000 ft2
Briskway Headway
0.72 fl. oz./ 1.000 ft2 3 fl. oz./1,000 ft2
Kabuto
3.42 fl. oz./ 1,000 ft2
Kabuto
2 fl. oz./10,00 ft2
Kabuto
1.47 fl. oz./ 1,000 ft2
Frame + T
In this research study, Lexicon, Velista, Fame + T and Kabuto suppressed and reduced the severity of SDS compared to the untreated check. Applications of Headway reduced the severity of SDS, but they did not reduce the diseased area or number of patches. Both rates tested of Kabuto showed the best control of SDS, but the disease is not currently on the label, and the product was applied above labeled rates for other diseases. In the photo below, you can see control by Kabuto compared to the untreated check in the background. This was the first year of testing Kabuto for the control of SDS, and it was applied at excessive rates. Future research will explore the consistency and efficacy of this product against SDS at more conventional rates. c
1 fl. oz./1,000
ft2
Table 1. Fungicides and rates used in this trial.
22 | Virginia Turfgrass Journal May/June 2016 www.vaturf.org
Untreated check
Kabuto 3.42 fl oz/ 1000 ft2 (1 app)