SEASON: Spring to fall.
APPEARANCE: The most obvious symptom of this disease is elongated circular spots on the grass blades. These spots have a brown or straw-colored center with black to purplish borders.
FAVORABLE CONDITIONS: Cool (50º to 70º F), moist conditions are most favorable for the growth of leaf spot. The spots first appear on grass in shady areas of the lawn. They occur most commonly during wet, humid weather or in lawns that are often lightly sprinkled or mowed too closely.
SUSCEPTIBLE GRASSES: Kentucky bluegrass, fescue, and Bermuda grass.
RESISTANT VARIETIES: 'Julia' and 'Midnight' Kentucky bluegrasses, 'Banner II' fine fescue, 'Cimarron' and 'Rebel II' tall fescues.