Source and Dispersal of Conidia of Drechslera poae in Kentucky Bluegrass Turf. A. K. Hagan, Extension Plant Pathologist, Alabama Cooperative Extension Service, Auburn University, Auburn 36849. P. O. Larsen, Professor, Department of Plant Pathology, Ohio State University, Columbus 43210. Plant Dis. 69:21-24. Accepted for publication 27 August 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-21.

Populations of conidia of Drechslera poae in Kentucky bluegrass turf and the atmosphere were monitored in 1979 and 1980. Leaf litter clippings, not thatch, were found to be the primary source of conidia. Conidia were first detected in leaf litter in late March. Populations of conidia in leaf litter were highest in May and June and fell to near zero by July. Airborne conidia were most numerous in mid-May through June, whereas few conidia were detected in early April to mid-May. Very few conidia were collected from early July through the remainder of the season. Diurnal conidial release was highest at 1200–1600 hours and correlated negatively with decreases in relative humidity.