Ascochyta leaf blight
Ascochyta spp.
A cosmetic but alarming blight that straw-colors large areas of Kentucky bluegrass almost overnight, usually after swings between wet and hot/dry weather.
Identification
Large, uniform straw-colored areas that appear suddenly. Blades die back from the tip with bleached lesions and look shriveled and pointy, yet healthy green blades are interspersed within affected areas. Crowns and roots stay healthy, so turf usually recovers.
Symptoms
Large straw-colored areas appearing suddenly. Leaves dying back from the tip with bleached lesions. Healthy green blades interspersed within blighted patches
Signs
Large, uniform straw-colored areas that appear suddenly. Blades die back from the tip with bleached lesions and look shriveled and pointy, yet healthy green blades are interspersed within affected areas. Crowns and roots stay healthy, so turf usually recovers.
Biology
Ascochyta leaf blight is caused by Ascochyta species, which act primarily as foliar pathogens on stressed turf. The disease affects leaf tissue while crowns and roots usually remain healthy, so recovery can be rapid once stress is corrected.
Epidemiology
Moisture extremes , wet soils followed by hot, dry conditions; drought stress from poor irrigation coverage or watering restrictions.
Favorable Conditions
Moisture extremes — wet soils followed by hot, dry conditions; drought stress from poor irrigation coverage or watering restrictions.
Cultural Management
Irrigate deeply and infrequently to even out moisture; avoid late-day watering. Reduce thatch and relieve compaction with annual core cultivation. Maintain a higher mowing height (6-7.5 cm) and keep mower blades sharp
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.