Necrotic ring spot is a disease caused in the spring by a soil fungus when too wet or dry with temperatures ranging from 10 to 20 º C. Lawn symptoms are circles ranging from 10 to 25 cm in diameter of yellow turf with a green grass in the middle of the circle. With increased disease virulence these circles overlap to form larger yellow areas. Some cultural practices to reduce disease virulence, do not over fertilize, mow high, dethatch if necessary and aerate the compacted soil. Do not over irrigate during periods of heat and drought.