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Etiology

Role of Pythium in Sugarcane Stubble Decline: Pathogenicity and Virulence of Pythium Species. J. W. Hoy, Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803; R. W. Schneider, Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. Phytopathology 78:1688-1692. Accepted for publication 21 July 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1688.

Ten isolates of Pythium arrhenomanes and a single isolate of P. spinosum caused root rot and significant reductions in growth of sugarcane cultivar CP 70-321 in pathogenicity tests. Isolates of six other Pythium spp. were tested, and none consistently affected plant growth. Disease severity was greatest in experiments conducted under moderate temperature conditions. In tests conducted at high temperatures, the predominant symptoms were root discoloration and feeder root necrosis, and a range in virulence was apparent among isolates of P. arrhenomanes.