as autumn leaves fall, superintendents in the South begin to worry about dealing with winter problems while accommodating more golfers. Experts offer advice on what some of these problems are and how to avoid them.
Spring dead spot
Although it is aptly named, spring dead spot begins infecting roots in the fall. That is when superintendents should apply a preventative fungicide to treat against the disease, says David Y. Han, extension specialist associate professor in Auburn University’s Department of Crop, Soil and Environmental Sciences. “You just have to go with something systemic,” he says. “I know a lot of people these days are using the DMI class of fungicides.”
Superintendents often pay more attention to above-ground appearance than they pay to roots, says Dr. Steve Kammerer, regional director of the USGA Green Section Southeast Region. Roots are affected by water movement, which becomes compromised when organic matter builds up.
Fighting against spring dead spot means supporting root growth, Han says. “The healthier the root system is, the more fungal infection it can withstand before you actually see symptoms,” he says.
Other measures lower chances of the disease appearing, such as maintaining quality aeration programs on fairways and checking pH levels, Han says. Superintendents should also avoid late-season nitrogen applications on fairways where they have had previous problems with spring dead spot, while monitoring potassium levels to avoid deficiencies.
Overseeding is stressful on Bermudagrass, says Dr. Aaron J. Patton, associate professor of agronomy in Purdue University’s Department of Agronomy. The overseeded cool-season grass places extra shade stress on the Bermudagrass; it takes long for the cool-season grass to die and for the Bermudagrass to green up. Additionally, the process is expensive.
As an alternative to overseeding, some superintendents are painting dormant Bermudagrass, Patton says. “In some areas of the Carolinas that’s become pretty popular, even into Georgia and those areas, as a way to keep part of the course, at least, looking green during the winter, so it looks like what golfers are used to, but they’re actually just looking at the color applied over the dormant Bermudagrass,” he says.
Some courses, such as coastal resorts that see heavy play in the winter, don’t have much of an alternative to overseeding, Han says. But it in general, overseeding is not the best practice. “It really does make a difference in the spring not having that Poa trivialis there to compete with the Bermudas coming out of dormancy,” he says.
Golf courses with ultradwarf Bermudagrass in the Transition Zone are prone to winterkill and would benefit from ordering snow covers, Patton says.
Covers raise the temperature of the turf when hard freezes occur, which is usually around 25 degrees, Han says. “The last really cold winter we had around here was – I guess it would be the winter of ’13-’14, and courses that covered lost a lot less grass on the greens than courses that couldn’t cover,” Han says. “The only courses in Alabama that lost entire greens were ones that could not cover; they didn’t own covers.”
Superintendents in the Transition Zone should often pull covers off during the day, though, because temperatures can fluctuate from the upper teens and low 20s at night to 45 degrees and sunny during the day, Han says.
If they don’t have snow covers yet but are considering them, superintendents would want to order them ahead of time, Han says. They are available in a variety of different materials. “A full set of covers for 18 holes can cost $40,000 or $50,000, but it’s well worth it,” Han adds.
September and October along with April and May are integral times to target nematodes, says Dr. William T. Crow, landscape nematologist in the University of Florida’s Entomology and Nematology Department. In areas where warm-season grasses go dormant, superintendents should treat for nematodes in the fall to improve grass health throughout dormancy and into the spring. “If you’re in areas where the grass doesn’t go dormant, like Southern Florida, you’re trying to manage your nematodes because you’re going into the big season when you’re going to get a lot of play and things really need to look good,” he says.
The damage that nematodes cause to roots can make them more susceptible to Bermudagrass decline and potentially Pythium root rot, Kammerer says. “By controlling or minimizing nematode damage, root pathogens are not as damaging,” he adds.
The fall presents an ideal time to control perennial broadleaf and grassy weeds, says Dr. Matthew T. Elmore, assistant professor and turfgrass extension specialist in Texas A&M University’s Department of Soil and Crop Sciences.
“The weeds are most obnoxious during the summer, so there are a lot of herbicide applications made in the summer,” Elmore says. “But in the fall, especially for weeds like dallisgrass, Virginia buttonweed and some of those more perennial weeds, fall applications are actually more effective than summer or spring applications.”
Research Elmore and colleagues have conducted on dallisgrass shows that programs used to treat the weed are most effective once the average temperature remains below 72 degrees for a few consecutive days. Researchers have not identified exact temperatures for many other perennial weeds, but in general, fall is the best time to treat them.