It’s the time of year in the Southeast, especially in Florida, when the weather pattern is a bit of a roller coaster. We find ourselves heading out in the morning with hoodies on and end up in short sleeves by lunchtime. This season ushers in cool fronts that bring moisture and extended cloudy days, but then we quickly return to humid and warmer conditions that often bring the worry of disease pressure on greens during the busy season when we need to be at our best.
Leaf spot (Bipolaris is the species of pathogen affecting bermudagrass; formerly known as Helminthosporium) is a common issue at this time of year on bermudagrass greens, and it is essential to remain proactive in managing this disease while navigating through fluctuating weather patterns and slower turf growth. Leaf spot is notorious for occurring during wet conditions, so taking proactive cultural steps to combat surface moisture and saturated soil conditions is a must. Running a spiker and instituting needle-tine aeration throughout the winter season on greens will aid with moisture management and oxygen exchange. For challenging areas along the perimeter of putting greens like edges that have collar dams, locations with extended shade or areas that retain moisture, weekly cultural practices should be implemented. Instituting a weekly cleanup pass with a needle-tine aerator will provide added support for the turf in these areas without disrupting play or putting surface quality. It is important to keep up with your sand topdressing program as growing conditions allow, raise mowing heights during stressful periods, and utilize lightweight rollers as part of your disease prevention strategy. While we cannot control the weather, monitoring irrigation cycles, performing distribution audits and hand watering ensures we are not unnecessarily adding moisture that can promote leaf spot outbreaks.
Additionally, making sure nitrogen inputs do not exceed one pound per 1,000 square feet monthly during winter will help avoid disease. Lastly, while cultural practices are vital, preventive fungicides must be part of the game plan during this delicate wintertime period. Rotating fungicides every 7-14 days with different modes of action is key. Fluazinam was always my go-to for leaf spot control, in combination or rotation with others.
As the tee sheets keep filling up and the weather keeps you on your toes, having a game plan for managing leaf spot and other winter issues will help you get through this unpredictable stretch. If you need support during this challenging period, please reach out to one of our regional agronomists, they are another tool at your disposal!
Southeast Region Agronomists:
Jordan Booth, Ph.D., senior director, USGA Course Consulting Service – jbooth@usga.org
Chris Hartwiger, director, Agronomy – chartwiger@usga.org
Chris Neff, agronomist – cneff@usga.org
Mitch Leininger, agronomist - mleininger@usga.org