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Ecology and Epidemiology

Settling Speed of Clusters of Spores. Francis J. Ferrandino, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, P.O. Box 1106, New Haven 06504; Donald E. Aylor, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, P.O. Box 1106, New Haven 06504. Phytopathology 74: 969-972. Accepted for publication 2 May 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-969.

The settling speed of single particles and different-sized clusters of Uromyces phaseoli urediospores, Lycopodium spores, and ragweed (Ambrosia elatior) pollen was determined by timing their fall in still air. The settling speed (v_s) of a cluster of N particles, regardless of shape, was described well by the equation (v_s)_cluster = 0.98(v_s)_single N^0.53.