Problem: Ascochyta Leaf Blight
This plant disease is caused by one of several related fungi (Ascochyta species) that invade leaf blades through wounds, usually the end cut by mowing. It attacks most of the turfgrass species grown in the part of the country where it is prevalent. The fungus spends the winter in the turf''s dead leaves. During warm, wet weather, sticky spores are splashed by raindrops or carried by feet or lawn mowers to fresh grass blades. The disease is most prevalent in the spring, but can occur any time during the growing season. It is favored by long wet periods, frequent irrigation, frequent mowing and dull lawn mowers. The disease usually doesn''t kill the infected patches of lawn. It may disappear without treatment, then reappear later that same season.
Ascochyta leaf blight may disappear without treatment. Long wet periods, frequent irrigation, frequent mowing, and dull lawn mowers can contribute to the disease. Water deeply and infrequently, early in the morning to allow the grass to dry quickly. Mow with a sharp mower, removing no more than 1/3 of the grass blade each time. Apply enough fertilizer to keep the grass green; too much nitrogen forces lush growth and more frequent mowing.