Each spring, as homeowners begin mowing, fertilizing, and watering their lawns, my telephone and email inquiries pick up with questions concerning turfgrass diseases. Over the next couple of weeks I will briefly describe some of the most common warm season turf diseases that attack our lawns and give some tips to keep them in check.
The first calls generally come from homeowners having dead circular patches in their hybrid bermudagrass lawns. Managers of golf courses and athletic fields are quite familiar with this root-infecting disease referred to as Spring Dead Spot. The symptoms of this disease problem is quite evident now as healthy turf breaks dormancy and begins to green. The diseased circular patches, however, remain brown.
The demise and eventual death of these patchy areas actually 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 as early as last summer, the symptoms were not evident then because of the turf’s regenerative capacity then. Once temperatures cooled below turf growth the disease got the better hand.
While filling in of these areas may be slow, usually the turf will recover by the end of the summer as healthy turf around these patches grows back into the dead spots. The disease often shows back up in the same areas in following years. 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 10, 2006
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. wwells@ext.msstate.edu
