Anthracnose on Bentgrass

Bentgrass (Agrostis) is a native grass of Europe and Asia and grows best in cool, humid climates. There are over 100 species of bentgrass, of which only four are widely used in the United States for lawns and sports fields. Anthracnose is a common disease of bentgrass.

Identification

Anthracnose is a fungal disease of bentgrass; the fungus Colletotrichum cereale is the culprit. The disease is most prevalent during warm summer temperatures between 80 to 95 degrees Fahrenheit.

Damage

The fungus takes the form of brown, irregularly shaped, 2- to 12-inch-diameter patches on grass. There are brown spots on individual grass blades. As disease progresses, grass dies and black fruiting structures are visible on dead blades. Older grass blades are affected first and most.

Management

Avoid over-fertilizing and over-watering lawns. Do not fertilize grass in warm weather. Reduce shade, aerate compacted lawns and increase mowing height. Avoid watering grass during late afternoon or evening as this does not allow grass to dry sufficiently and favors fungal growth.

References

• Texas A&M University Extension: Bentgrass
• Kansas State University Extension: Anthracnose of Bentgrass and Annual Bluegrass Putting Greens
• University of California Extension: Anthracnose