Now that warm season turfgrasses are greening up from winter dormancy, I have received several calls about dead circular patches in burmudagrass lawns, athletic fields, and on golf courses. The symptoms of this disease problem are quite evident now as healthy turf breaks dormancy, begins to green, and the diseased patches remain brown. However, the actual death of the turf began as early as last fall and through the winter months.
There may be one or more pathogens (Leptosphaeria spp., Gaeumannomyces spp., Ophiosphaerella sp.) infecting and colonizing the roots and stolons of the bermudagrass. Even though the infection began last fall, the symptoms were not evident then because the turf still had regenerative capacity. Once temperatures cooled below turf growth the disease got the better hand.
While filling in of these dead areas may be slow, usually the turf will recover by the end of the summer. A slightly lower cutting height to encourage lateral growth, keeping thatch to a minimum, aerification to stimulate root growth, and a well-balanced fertility and watering regime will speed recovery.
Weed competition must also be managed. To reduce the severity of spring dead spot next winter avoid late growing season high nitrogen fertilization, maintain adequate potassium levels, keep thatch levels below three-quarters of an inch, and raise the mowing height towards the end of the growing season. Fall applications of selected fungicides have given some protection.
Published April 11, 2005
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. firstname.lastname@example.org