SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/107950
FieldScience >> FIGURE 2. White tissue symptoms that normally occur from the topramezone treatments (center plot is topramezone alone) are reduced or nearly eliminated and bermudagrass control increases dramatically when topramezone is tank-mixed with triclopyr (plots on left or right) (photo courtesy of Shawn Askew). mon and immature turf will always be present due to the need to manage wear areas. Dr. Askew's research suggests that fenoxaprop + triclopyr should only be used in early spring or late fall where immature turf is less prevalent and should be replaced with mesotrione or mesotrione + triclopyr at low rates during stressful periods of summer. Applications of either mesotrione or fenoxaprop mixed with triclopyr can effectively control bermudagrass in cool-season grasses. Just remember to reduce triclopyr rates in hot weather and on Kentucky bluegrass, switch from fenoxaprop to mesotrione both to save money and reduce potential damage to the bluegrass during stressful summer weather, and concentrate on fall treatments to get the best kill (repeat treatments at a 3-4 week interval). Two new herbicides that are currently under investigation by Dr. Askew's group include topramezone and metamifop. Both herbicides show great promise for selective bermudagrass control and topramezone could be registered within the next year (Figure 2). Both herbicides work better when mixed with triclopyr but offer superior turf safety and bermudagrass control to other herbicides currently on the market. No herbicide, however, will control bermudagrass alone but must be mixed with other herbicides and applied 4-6 times per year in a program approach to bermudagrass eradication. 16 SportsTurf | February 2013 TURF TOLERANCE TO RIGID TURF PROTECTION SYSTEMS–Erik Ervin. Dr. Erik Ervin is a Professor of Turfgrass Physiology in the Crop and Soil Environmental Sciences department of Virginia Tech and has primary responsibilities in teaching and advising in the undergraduate program. This research brief summarizes work supported by VT Athletics and the U.S. National Park Service and was completed in 2012 by M.S. student John Royse. The presidential inauguration, the national book festival, the solar decathlon, and a U2 or Dave Matthews Band concert: what do these events have in common? They are all multi-day set-up and takedown events (often involving cranes) that take place on natural turfgrass surfaces (e.g., the National Mall and MLB fields) with thousands of attendees. Many times the activities are so intense that major turf death occurs and complete re-grassing is required. Managing or softening the conditions that cause major turf loss, however, is preferred. Unfortunately, there have been almost no scientific studies investigating the positives and negatives of current practices. In 2010 and 2011 we conducted multiseason event cover simulation trials to determine how long a mature tall fescue turf (2.5 inch mowing height on a silt loam soil) could survive and what some of the controlling factors might be (e.g., light, compression resistance, soil moisture, temperature). Two commercially available rigid high-density polypropylene covers were compared to plywood-alone or plywood over Enkamat (Table 1). Terratile is a single-sided, white, translucent cover with foot pads and air holes used primarily for seating or foot-traffic protection, while Matrax LD is a double-sided, white, translucent cover with no air holes used primarily for vehicle-traffic protection. Each spring, summer, or fall season covers remained on the turf for 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20 days giving us a look at turf persistence and recovery every 2 days during a 3-week period (Figure 3). Using linear regression we were able to estimate how long tall fescue could be covered (and driven over daily with a truck) and not have more than 40% turf loss (Table 1). We found that light availability played a major role in turf persistence and recovery. The translucent Terratile and Matrax prod- Table 1. Light transmission, average maximum high temperature under cover, and the predicted days until 40% or greater tall fescue loss following covering of various turf protection systems in summer or fall/spring. High temperature under cover Number of days under cover before >40% turf loss, tall fescue Cover name Light transmission Mean across 2 summer seasons (oF Summer1 Fall/Spring1 Terratile Matrax LD Plywood over Enkamat Plywood 25% 5% 0% 108 100 101 10 12 1 >20 >20 5 0% 104 1 5 1 Average high air temperatures during the two summer test periods was 94oF, while that over the four spring and fall test periods was 70 oF. www.sportsturfonline.com