Diseased LawnAscochyta Leaf Blight is a fungi that attacks grasses during much of the growing season when humidity and atmospheric moisture are high or when irrrigation and mowings are frequent. The grass blade is usually killed from the tip down towards the base of the plant. This disease is common when a cool, wet spring is followed immediately by hot summer conditions. Ascochyta is most severe when the turf becomes stressed due to a combination of high heat and improper irrigation.