Management of Turfgrass Diseases and Thatch by Streptomyces and Fungi

Problems associated with turfgrasses include thatch accumulation and fungal diseases such as dollar spot, brown patch, and Pythium crown/root rot. Excessive thatch accumulation, in turn, exacerbates disease prevalence and degrades turf quality. Approximately 40 million acres are planted in turf in the U.S. About 20% of all fungicides used in the U.S. are applied to turfgrasses, which is greater than that applied to any other single horticultural or agronomic crop. Due to the high usage rate of pesticides and the intimate contact humans have with turfgrass, safer alternatives are required. We propose research utilizing a synergistic approach towards biological control of turf diseases, enhanced thatch biodegradation with ligninolytic Streptomyces and white-rot fungi, and iron mobilization on a commercial iron-humate product with active siderophore-producing Streptomyces. A portion of the research will address the feasibility of formulating a value-added biological through compatibility experimentation of the de-thatch microorganisms with Streptomyces lydicus WYEC 108, a commercial biological control agent. A stand-alone lignin-degrading Streptomyces/fungus formulation with biological control, de-thatch, and iron-mobilizing properties will also be developed. Research will include compatibility testing of Streptomyces with white-rot fungi and fungicides, microbial population dynamics, siderophore assays and in vivo de-thatch and challenge experiments.