Impact of a Zoysiagrass and Tall Fescue Seed Mixture on Brown Patch Disease Severity.

Hot summers and cold winters make it difficult to grow cool and warm-season turfgrasses, respectively. Tall fescue is used frequently in Kansas due to its heat and drought tolerance compared to some other cool-season grasses. Brown patch caused by the fungus Rhizoctonia solani Kühn AG-2-2 IIIB is the main disease limiting the growth of tall fescue in summer, and brown patch resistance in tall fescue cultivars is limited. Earlier research has demonstrated that polystands of zoysiagrass and tall fescue can be established successfully, with the potential to provide a quality turfgrass stand with prolonged winter color and reduced inputs. Our objective was to determine whether a polystand composed of a seeded zoysiagrass (‘Compadre’) and tall fescue (‘Corona’) will reduce brown patch severity while maintaining overall acceptable quality. Studies were established at the Rocky Ford Turfgrass Research Center in Manhattan, KS and Olathe Research Center, Olathe, KS in 2015. In the split plot design, natural infection by R. solani or a fungicide-treated control was the whole plot treatment factor and species (tall fescue monostand and the polystand mixture) were subplots. During July and August 2016 and 2017, nightly irrigation was applied to promote brown patch. Disease severity was measured by rating the percentage of each plot affected by brown patch. Across both years and locations, brown patch disease severity in the tall fescue monostands was up to 22% higher than the tall fescue/zoysiagrass polystand during July and August. Turf quality was also consistently higher in the polystand compared to the monostand during peak brown patch outbreaks. Use of a tall fescue/zoysiagrass polystand is one option to reduce brown patch in transition zone lawns where the disease is common.