Diseases and the names used to describe them are abundant on Kentucky bluegrass lawns. One of these problems, a leaf blight, can occur whenever the grass is green. Called Ascochyta leaf blight, this disease is stress related. For example, it may occur on newly sodded turf, or any established lawn that has experienced a dry period. These dry periods can occur in the dead of winter or the heat of summer.
Once the dry period ends, Ascochyta symptoms may appear. If this fungus is present, grass blades will turn straw-colored or appear bleached. The tips of the now straw-colored grass blades will shrink or wither, causing the leaf tip to appear pinched.
Chemical control of Ascochyta rarely is warranted. The presence of leaf blight is an indication that you need to adjust your watering practices. Be sure to water grass once a month during prolonged winter dry spells. In the spring and summer, monitor irrigation to make sure water coverage is adequate, depending on temperature and weather conditions. Water management is the key to a healthy lawn.
For more information, see the following Colorado State University Extension fact sheet(s).