Fall is the Time to Control Spring Dead Spot in Bermudagrass
Elizabeth Little,
Homeowner IPM Specialist with the UGA College of Agricultural and Environmental Sciences
Spring dead spot, or SDS, is one of the most common and important diseases on bermudagrass in Georgia. It
is difficult to manage Spring Dead Spot without an integrated approach. This fungus disease is most common
on intensively maintained turf like golf courses or lawns.
SDS causes dead patches
The characteristic dead patches appear in the spring when the grass is breaking dormancy, and the problem
can persist well into summer. The fungus that causes the disease attacks the roots and stolons in the fall and
winter. This makes the grass more vulnerable to winter freeze damage, which leads to the dead patches of
grass.
Late September through October is the best time to apply preventative fungicide applications if SDS has been
a problem this past season. But this won’t provide complete control. Most infections can be eventually
eliminated over a period of years by combining fall fungicide applications with sound cultural practices.
Maintaining a disease free lawn in the coming years can only be accomplished by eliminating the stress that
allowed the disease organisms to attack the lawn in the first place. Lawns are stressed by poor soil conditions
combined with an imbalance of nutrients. Compaction, poor drainage and thatch thicker than one inch are also
linked to SDS outbreaks.
Follow these tips
Applying nitrogen late in the season or excess nitrogen, especially with a potassium deficiency, can encourage
the development of disease. An integrated management program to improve the lawn’s health includes the
following steps:
• When planting new lawns, use cold tolerant cultivars.
• Aerate and remove thatch regularly.
• Irrigate deeply and less frequently. (Once per week in the absence of adequate rain.)
• Mow at the recommended height. Low-mowing height stresses lawns.
• Monitor pH and nutrient levels on a regular basis with soil tests. Keep potassium and phosphorus in balance
with nitrogen.
• Maintain a pH between 5.5 and 6.0 if disease has been a problem. The pH can be lowered by using
ammonium sulfate as a nitrogen source.
• Apply moderate levels of potassium in September and October to increase cold hardiness. If a deficiency of
potassium is indicated on a soil test, two applications of potassium sulfate or potassium chloride can be
applied at a 3 to 4 week interval for a total of 1 lb. of K2O per 1,000 sq. ft. Excess potassium should be
avoided as it can also encourage disease.
• Do not apply nitrogen after August. Nitrogen should be added in recommended amounts in late spring and
early summer. Use moderate amounts of nitrogen during the summer so that excess nitrogen is not carried
over into the fall.
• Apply fungicides in late September or October if SDS was a problem the previous spring. These fungicide
recommendations are for commercial turf managers and are provided by Dr. Lee Burpee, UGA Plant
Pathologist. Homeowners can find fungicide recommendations in the Pest Management Handbook or though
their local Extension Office.
“Rubigan (fenarimol) continues to be the standard for control of SDS. In the Piedmont region of Georgia, apply
Rubigan at 6 oz./1000 sq.ft. in late September or early October. A split application of 4 oz. in late
September/early October followed by 4 oz. in late October/early November is also effective.
The Rubigan label advises applying irrigation after spraying. However, effective control has been achieved by
applying Rubigan in at least 2 gallons of water per 1000 sq.ft. with no follow-up irrigation.” 1
Other warm-season grasses, such as zoysia, centipede and St. Augustine, will also benefit from these general
recommendations to prevent diseases like take-all and Rhizoctonia large patch. Follow recommendations for
fertilizer applications for the particular grass species. A pH of approximately 5.5 to 6 is generally optimum for
warm-season grasses.
See these sites for more help
For more information on maintaining turfgrass in Georgia, see the website www.Georgiaturf.com. For
fungicide recommendations, contact your local University of Georgia Cooperative Extension agent or consult
the Georgia Pest Management Handbook at www.ent.uga.edu/pmh/.
1
Lee Burpee, UGA Professor of Plant Pathology, Warm Season Disease Management in 2010 Turfgrass Field
Day Guide page 12.
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