Ascochyta leaf blight

Ascochyta leaf blight

Wednesday, June 29, 2022

Author: Roch Gaussoin, PhD, Extension Turfgrass Specialist

Most resources indicate that Ascochyta leaf blight is a minor disease because injury is usually temporary, and does not result in turf loss. Kentucky bluegrass is most commonly affected, but infection of other cool-season grasses is also possible. Outbreaks of this disease have been common as far west as central Nebraska this year.

Symptoms. Ascochyta may appear in isolated spots, or as large patches of straw-colored turf (similar to drought stress, but soil will likely be moist). Symptoms commonly appear following wet weather from late spring to summer, but infection may occur all season. Infections may also appear uniform and diffuse (Figure 1). Individual leaves bleach from tips, and sometimes have dark brown elliptical lesions with dark fruiting bodies called pycnidia.