VIEW ARTICLE

Techniques

An Evaluation of Optical Density to Estimate Fungal Spore Concentrations in Water Suspensions. S. C. Morris, Research Horticulturist, Gosford Horticultural Postharvest Laboratory, New South Wales Department of Agriculture, P.O. Box 355, Gosford, NSW, Australia 2250; P. J. Nicholls, Senior Biometrician, NSW Department of Agriculture, State Office Block, Phillip Street, Sydney, NSW, Australia 2000. Phytopathology 68:1240-1242. Accepted for publication 28 February 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1240.

Optical density (or turbidity) was used to estimate a wide range of spore concentrations of Penicillium digitatum, Penicillium italicum, and Geotrichum candidum. Four strains of each were used, and for each organism, optical density was closely related to spore concentration determined by haemocytometer count.