TURFGRASS DISEASE MANAGEMENT

Turfgrasses are most susceptible to disease when they are stressed or growing slowly. As a result, the most severe disease problems on cool-season grasses occur during the summer, and most diseases in warm-season grasses develop in the fall and spring. Grasses that are healthy and vigorously growing are far more resistant to disease than grass that is poorly managed, and they will also recover more quickly should disease develop.

Fungicides can be used to control turfgrass diseases. Fungicide applications may be preventive, if made before symptoms of the disease appear, or curative, if made after symptoms appear. Preventive fungicide programs are recommended for diseases that occur annually. Curative fungicide applications are less effective and usually require increased application rates or shorter application intervals. Whenever possible, schedule preventive fungicide applications based on the weather conditions that favor disease development, not based on the calendar. A disease must be identified accurately in order to select the best fungicide for its control.

Many systemic fungicides lose effectiveness due to the development of fungicide resistance. Fungicide resistance occurs when fungicides from the same chemical class are applied repeatedly. Repeated applications allow strains of the pathogen that are naturally resistant to the fungicide to build up in the population. When resistant strains become dominant in the population, the fungicide no longer controls the disease, and significant damage may occur when conditions become favorable for disease development.

HOW TO USE THIS PROGRAM

• Select the turfgrass type (use) that applies in your situation.
• Select from one to three turfgrass species that are present and affected by disease. Click the “Submit Turfgrass Selection” button which appears at the bottom of the screen.
• Select from one to five diseases which are present in your situation. Not sure about disease identity? Click on the disease name for description, pictures, and cultural control information. After checking diseases of interest, click on the “Submit Disease Selection” button which appears at the bottom of the screen.
• A list of fungicides will appear. This list shows the efficacy and resistance ratings for each fungicide against each selected disease. The list is sorted according to average overall efficacy, fungicide class, and then common name. To sort the list by efficacy or resistance rating for a particular disease, click on the appropriate column heading.
• To view details on recommended fungicide rates and application intervals, check the fungicides of interest (up to five), then click on the “Submit Fungicide Selection” button at the end of the fungicide table.
• You may view and/or change any of your selections by clicking on the [+] showing to the right of the first four steps listed at the top of the screen.

CREDITS

This program was created by faculty and staff in the Departments of Crop Science and Plant Pathology, College of Agriculture & Life Sciences, North Carolina State University. This program was made possible through a grant provided by the Center for Turfgrass Environmental Research & Education (CENTERE) whose purpose is to support worthwhile projects that will benefit both the private sector and the public, and protect the environment.

Programming, design, and computer support

Vimal Chungath, Greg Buol, Mike Sturgill

Project management and planning

Gail Wilkerson, Lane Tredway

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