Rotorod, Kramer-Collins, and live-plant spore traps were used to determine the seasonal periodicity of dispersal of D. poae conidia. Conidial dispersal was first detected in the spring at the beginning of grass growth or about the time of 1st mowing. Spore collection reached a maximum in mid-May and by late June had almost ceased. More conidia were detected on days when the turf stand was mowed than on those when the grass was not disturbed. Conidial collection was greatly reduced at heights above 7 cm.