MANAGEMENT OF ANNUAL BLUEGRASS ON GOLF COURSES: IMPROVED PRACTICES FOR MAINTENANCE, PEST CONTROL, AND VIABLE TECHNIQUES FOR TRANSITION TO MORE DESIRABLE GRASSES

Annual bluegrass (ABG) is a highly invasive weed on golf courses where it frequently becomes the dominant species despite attempts to suppress it. As a result, superintendents usually resort to managing it instead of more pest-tolerant bentgrasses. The annual bluegrass weevil (ABW) and anthracnose basal rot (ABR) disease, caused by the fungus Colletotrichum cereale, have become the most severe pests of ABG. Their control often depends heavily on pesticides. Extensive pesticide use has resulted in insecticide and fungicide resistance. We will focus on the ABR portion of this project. There is an urgent need to gain a better understanding of the biology, and pathogenesis of ABR, develop improved IPM tools for more effective pest management, learn how stresses affect ABG and its sensitivity to ABR, and how to either mitigate these stresses or find ways to transition to more desirable/sustainable grasses. General methods will include development of new molecular tools to study C. cereale and the infection process. The impact of nitrogen, cultivation and other cultural practices on ABR will be assessed. These finding will be used to establish a final 'proof of concept' study (2013-15) to show the effect of best management practices (BMPs) on ABR, fungicide effectiveness, and ABG quality. New fungicide, biological and biorational products, and application strategies will be studied. Practices that delay or reduce the potential for fungicide resistance will also be assessed. The tolerance/resistance of ABG and bentgrass varieties to ABR will be evaluated in the greenhouse and field. Diagnostic methods will be developed for better ABR detection. The effects of environmental stress on ABG and its susceptibility to ABR will be determined. A survey will be conducted (yr 1) to assess industry practices for the suppression/transition of ABG to more sustainable grasses. Cultural techniques (e.g., use of overseeding species; cultivation; soil fertility), alone or in combination with novel biocontrols and herbicides to reduce/eliminate ABG in favor of more desirable turfgrass species will be studied. Tolerance/resistance of ABG and bentgrass species varieties to ABR will be evaluated in the lab and field. The impact of project findings will be assessed via outreach programs and stakeholder surveys (yr 5). Expected outcomes: 1). Improved exchange of information among turfgrass scientists in the U.S. and Canada. 2). Increased knowledge of practitioners for the control of ABR and ABG. 3). BMPs adopted by turf managers including new biological, biorational, cultural and chemical control techniques. This will result in practitioners having: (a) a better understanding of the management of ABG and ABR; (b) more effective control strategies for ABR that are cost-effective and reduce reliance on chemical inputs; (d) optimal programs for ABG maintenance, and (e) optimal methods for ABG suppression, elimination, and transition to more desirable grasses. Adoption of this information by practitioners will result in reduced pesticide inputs, cost savings, and improved plant health.