A Cylindrosporium Leaf Spot On Oak

Abstract

A Cylindrosporlum fungus was consistently associated with and isolated from circular leaf spots on Quercus rubra. It was examined in pure culture and on leaves by light and electron microscopy and identified as C. quercus Sorok. Growth of the fungus in culture was best at 27°C; germination of conidia was best at 24-27°C. Typical symptoms were produced on only 1 of 56 inoculated oak seedlings. This report is the first of C. quercus in Illinois and the first of a Cylindrosporlum on Q. rubra.