Feature Story
Spring Dead Spot and Large Patch – Spring Diseases that Need Fall Attention By Michael D. Richardson, Ph.D., Professor of Turfgrass Management and Physiology, University of Arkansas Department of Horticulture
W
arm-season grasses like bermudagrass and zoysiagrass are usually preferred in environments such as Arkansas and parts of Tennessee, as they are more tolerant of heat, drought, insects and diseases compared to cool-season turfgrasses. However, that does not mean they are bullet-proof! All of the major warm-season grasses used in these areas can have fungal disease problems and the most severe diseases are spring dead spot and large patch. Spring dead spot (SDS) is primarily a concern on bermudagrass, while large patch can infect all of our warm-season grasses. The University of Arkansas turfgrass program has evaluated various cultural and chemical strategies to control these diseases for many years and we continue to evaluate new products and practices that can be used to manage the diseases.
Spring Dead Spot (Ophiosphaerella herpotricha or O. korrae) Spring dead spot is often observed on turf that has been established for several years and especially in lawns or sports turf with excessive thatch. Spring dead spot is considered a “perennial disease” which means that it will show up in the same spots or areas year after year if conditions are favorable. Spring dead spot is often more severe in areas that are over-fertilized and typically more severe in high pH soils (>6.0). In turf areas with heavy SDS pressure, changes in cultural practices are important for longterm disease management. Verticutting and core-aerification to encourage aggressive stolon and rhizome formation and rooting is beneficial for SDS management. This should be done when the turf is actively growing. As the name implies, SDS symptoms appear as the bermudagrass begins to green-up (Figures 1 and 2), but infection and
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TENNESSEE TURFGRASS August/September 2019 Email TTA at: info@ttaonline.org
