First Report of Pythium myriotylum on Sugarcane in Australia. B. J. Croft, Bureau of Sugar Experiment Stations, P.O. Box 566, Tully 4854, Queensland, Australia. . Plant Dis. 72:1077. Accepted for publication 19 July 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-1077C.
Pythium myriotylum Drechs. was isolated from sugarcane (Saccharum interspecific hybrid cv. Q90) and sorghum (Sorghum bicolor (L.) Moench cv. FS26)seedling baits grown in soil from fields of sugarcane affected by poor root syndrome in Queensland, Australia, in 1985. P. myriotylum caused large red-black elliptical lesions on the roots and a rot of the root tips and significantly (P0.05) reduced the dry weight of roots of sugarcane cv. Q90, grown for 6 wk in sterile potting mix inoculated with a hyphal suspension. The fungus was reisolated from inoculated plants. Similar symptoms have been observed on sugarcane roots in fields affected with poor root syndrome. P. myriotylum has previously been identified from sugarcane in Taiwan (2). Poor root syndrome is caused by a complex of organsisms, including P. gramincola Subr., an unidentified comycete, and nematodes, and is a major disease of sugarcane in Queensland (1). The syndrome is characterized by a soft, flaccid rot of the primary roots, lesions and general discoloration of primary and secondary roots, and poor fine root development. P myriotylum is now believed to be a component of this disease complex.