Spring Dead Spot is probably the most destructive turf pathogen affecting bermudagrass turf. The causal organism of Spring Dead Spot is Ophiosphaerella, a soil borne pathogen considered to be indigenous to most southern United States soils. Three species of Ophiosphaerella have been identified (korrae, herpotricha and narmari) with korrae being the most common to our area. Spring dead spots are generally round in shape and can range from 6" to 1'-2' in diameter, but in severe cases, the spots will coalesce into large, irregular patches. The infected turf is actually dead as the name suggests and will have to be replaced or encouraged to fill in from the edges.
Weak turf that is under stress from, agronomic, physical, or climatic factors is especially vulnerable to Spring Dead Spot. This may be why we have seen so much of it this spring due to the harsh wet, cold winter we had. The pathogen infects the turf’s root system in the fall eventually causing the plant's vascular tissue to clog preventing the normal flow of water and nutrients. Over the course of the winter, when the turf is dormant, there are no symptoms evident and everything appears normal. In the spring though, as the weather begins to warm, the infected turf is unable to draw upon reserves of water and nutrients to break dormancy. Some affected turf may appear to green up as healthy turf would, but it quickly declines as the plant is starved for energy from the clogged vascular tissue.
Research to this point has not found a consistent cure for this disease. However, a preventative management approach incorporates a wide range of cultural, agronomic, and chemical control techniques. Factors to consider include, but are not limited to mowing height, fertility, aerification, thatch management, pH, and fungicide use.
Published May 24, 2010
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
