Location: Foreign Disease-Weed Science Research
Project Number: 8044-22000-051-008-N
Project Type: Non-Funded Cooperative Agreement
Start Date: Oct 1, 2019
End Date: Sep 30, 2024
The overall objective of this research is to provide outstanding dollar spot control on turfgrass using fewer fungicide inputs for all regions of the country that regularly experience dollar spot through improved host resistance, combinations of effective cultural practices, and better understanding of the genetic variability present within the pathogen population. Objective 1. Improve our understanding of dollar spot biology and epidemiology through taxonomic analysis, molecular assay development, and host-pathogen interaction research. Objective 2. Assess current dollar spot resistance among bentgrass cultivars and new selections, identify barriers to their utilization in golf course establishment and renovations, and develop strategies for overcoming the identified barriers. Objective 3. Develop cultural-based dollar spot management strategies that combine multiple cultural practices (e.g., fertility, rolling, topdressing, irrigation) to limit dollar spot development in multiple geographic regions. Objective 4. Develop integrated and targeted chemical dollar spot management strategies that maintain current levels of disease control, potentially reduce chemical inputs, and limit development of fungicide resistant populations. Objective 5. Assess the ability of antagonistic organisms to suppress dollar spot when combined with the aforementioned cultural and chemical strategies.
Turfgrass landscapes cover approximately 50 million acres of land in the U.S. and provide numerous environmental, recreational, and economic benefits. The 14,000+ U.S. golf courses only account for approximately 5% of the total turfgrass area; however, the golf industry’s economic impact is currently estimated to be over $84 billion in the U.S. Dollar spot is the most economically important disease of golf course turfgrass. Recent market data found that the average golf course in the Northeastern U.S. spends over $20,000 annually on fungicides to control dollar spot, well more than any other turfgrass disease. Recent advances in host resistance, predictive modeling, biological control, and pathogen genetics have offered exciting potential avenues for improved dollar spot control while using fewer fungicides. USDA-ARS and Rutgers scientists recently clarified the taxonomic classification of the pathogen and their work has generated important new questions regarding the genetic variability inherent in field populations. Since the reclassification of the dollar spot fungus in 2018 there has been a great deal of uncertainty surrounding the genetic variability of Clarireedia over a large geographic area. In particular, recent reports of aggressive fall dollar spot have led to questions about whether a different strain or species of dollar spot occurs in the fall relative to the summer. The project team will use a multi-faceted, multi-disciplinary approach to accomplish the objectives, working to identify the most dollar spot resistant bentgrass cultivars; to assess a range of cultural and biological control practices (fertility, dew removal, lightweight rolling) for their ability to control dollar spot without the use of chemical fungicides on both susceptible and resistant cultivars; and to use both morphological and molecular based methods to determine the genetic variability of the dollar spot pathogen that exists within and between regions. Overall, the research results collected by this research team will save golf course superintendents money and reduce fungicide input into the environment on golf courses from Maine to Missouri and Minnesota to the Carolinas.