Leaf Spot Disease: A Concern For Many Florida Golf Courses February 3, 2011 By John Foy

Outbreaks of leaf spot disease on bermudagrass putting greens, tees, and fairways, continues to be a concern at many Florida golf courses.  


The Florida winter golf season is in full swing, and, while the golfers are out there, many courses report that rounds continue to be down.   Even with diminished rounds, typical winter season concerns occur about deterioration in course conditions due to traffic.   Few golfers fully appreciate the significant negative impact of moderate to heavy daily play and cart traffic when the base turf is in a semi- to fully-dormant phase.  Complaints about very tight and penal fairway lies, and loss of definition between fairway and rough cuts, are common at this time of year.  Regardless of inputs, producing a quick recovery is not possible until daytime and nighttime temperatures are in the mid-80 and mid-60 degree range, respectively. For South Florida, this won’t be for another few weeks.

As if there wasn’t enough to worry about, an explosion of disease activity occurred throughout the region during the last two weeks of January.  This was not totally unexpected, given the environmental conditions.  Throughout the peninsula, cool nights and daytime highs in the mid-60 to mid-70 degree range, were combined with high relative humidity, heavy dew formation, and a slow morning burn-off.  There also were occasions when heavy cloud cover throughout the day resulted in the persistence of free surface moisture -- an ideal scenario for rapid spore germination and growth of fungal disease pathogens.  Based on recent TAS visits and superintendent phone calls, a major outbreak of leaf spot disease has been experienced on bermudagrass putting greens, tees, and fairways. 

Purplish-black leaf spot lesions can always be found on bermudagrass leaves.  However, because the causal organisms are weak secondary pathogens, this is not a major disease concern.  That is, except when the turf is in a weakened or stressed condition and environmental conditions are favorable for rapid disease development.  Although outbreaks of leaf spot disease do not typically cause extensive damage and turf loss, turf quality is impacted, along with growth and recovery.  Preventing and controlling outbreaks on bermudagrass putting greens with appropriate fungicide treatments is absolutely needed.  The extended forecast for the first half of February calls for a continuation of the current pattern, so a proactive disease control program is strongly advised. 

While there have been a few instances where broadcast fungicide applications have been necessary to control leaf spot disease on bermudagrass fairways and roughs, this is not a common practice at most Florida golf courses.  Along with judicious nitrogen fertilization and maintaining sufficient potassium levels, irrigating deeply and infrequently to keep the turf surfaces as dry as possible, but not allowing the onset of drought stress, are the recommended practices for surviving leaf spot outbreaks until bermudagrass growth resumes.  Recovery from winter season traffic damage cannot be expected for several more weeks; however, in addition to continuing aggressive traffic management, supplemental small tine aeration to alleviate soil compaction, and fertilization, can help prevent further deterioration. 

The 2011 TAS invoices will be mailed in the next few weeks to all Florida golf courses that have had a TAS visit in the last five years.   The full price rates for both half and full day visits will increase by $100, but the early payment discount will increase to $600.  This change allows those who choose the early payment option to have pricing stay the same as 2010.    

2011 TAS Fees:

Half Day:  $2400

 Full Day: $3200

A $600 discount will apply for payments received prior to May 15, 2011.

Call our office to schedule your winter season TAS visits.

Source:  John H. Foy, director, Florida Region, USGA Green Section (772) 546-2620,