Yellow ring
Trechispora alnicola
An uncommon, mostly cosmetic disease of Kentucky bluegrass caused by a fairy-ring relative, appearing as yellow rings.
Identification
Distinct yellow rings in the turf with abundant white mycelium in the thatch; stands usually recover quickly when growing conditions improve.
Symptoms
Symptoms are distinctive but often temporary lemon-yellow to golden-yellow rings in the turf canopy.
Signs
White mycelium may be present in the thatch, and affected areas can have a mushroom-like odor.
Biology
Yellow ring is caused by the fungus Trechispora alnicola and primarily affects Poa species.
Epidemiology
The disease appears during cool, moist periods in mid-spring and autumn, with activity favored when temperatures are approximately 68-77°F.
Favorable Conditions
Thatchy turf; a relative of the fairy-ring fungi.
Cultural Management
Vertical cutting and core aeration can disrupt the fungus, and reducing thatch can help limit disease expression.
Further Reading
University extension resources — open in a new tab.
Related Reports
No published reports yet for this pest.
Reports will appear here as they are peer-reviewed and published.