Clip 'N Keep:
Common Turf Misdiagnoses

By Pam Charbonneau, OMAFRA Turfgrass Specialist

One of the greatest challenges as a turf manager or someone in a lawn care business is to correctly identify turf problems. As a colleague of mine once said, "When turf has a problem, it turns brown, regardless of the cause of the problem." This is what makes diagnosing turf problems interesting. This article presents some of the common turf misdiagnoses. Hopefully, this information will be of assistance to you this coming season when you are faced with turf problems to diagnose.

Common misdiagnosis: Hairy chinch bug damage
Actual problem: "Melting out" stage of leaf spot.
Season of occurrence: In the late spring, early summer during warm weather following rainy weather.
How to distinguish: Turf that is "melting out" will have brown oval lesions with yellow centres at the base of the bluegrass plants. These lesions will completely girdle the bluegrass plant causing death. There may be hairy chinch bug adults present when melting out occurs, but they are usually adults, which are laying eggs for the upcoming season.

Common misdiagnosis: Unknown turf disease.
Actual problem: Bluegrass billbug damage.
Season of occurrence: Mid-July to mid-August.
How to distinguish: Entire turf blades turn yellow from the top down. Usually only small turf areas affected. When thatch is examined, there is sawdust frass and white crescent shaped, leg-less larvae present.

Common misdiagnosis: Drought.
Actual problem: Hairy chinch bug damage.
Season of occurrence: Mid-July to mid-August.
How to distinguish: Hairy chinch bugs will feed on dormant lawns. Even dormant lawns should be inspected for hairy chinch bugs. When the rain comes in the fall, the damaged lawns will not green up and will need to be overseeded.

Common misdiagnosis: Pythium blight.
Actual problem: Traffic from lawnmowers, fertilizer spreaders on turf during periods of high temperatures and low soil moisture causing yellow striping of turf.
Season of occurrence: In the summer during periods of high temperatures and low soil moisture.
How to distinguish: Pythium symptoms are collapsed water soaked grass leaves with white mycelium during hot humid nights. Most common on heavily fertilized turf on golf courses.

Common misdiagnosis: Brown patch.
Actual problem: Patches of rough bluegrass which die when drought stressed.
Season of occurrence: In the summer at the first onset of hot, dry weather.
How to distinguish: Look to see if the dead patch looks like a different species of turf.
Rough bluegrass can be identified by its very fine leaf blades and long creeping stolons.