Disease Note.

Damping-off of Fodder Beet Induced by Pythium salpingophorum in Colorado. E. G. Ruppel, USDA-ARS Crops Research Laboratory, 1701 Center Avenue, Fort Collins, CO 80526. M. E. Stanghellini, and E. E. Schweizer. Department of Plant Pathology, University of Arizona, Tucson 85721; USDA-ARS Crops Research Laboratory, Fort Collins. Plant Dis. 72:175. Accepted for publication 1 October 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0175B.

Severe preemergence and postemergence damping-off (60-70%) of fodder beet (Beta vulgaris L.) occurred in several commercial fields near Eaton, Colorado, in June 1987. Pythium salpingophorum Drechs. was consistently isolated from diseased seedlings. A moist, 2-wk-old sandoatmeal culture of a hyphal-tip isolate of the fungus was used to infest pasteurized soil (1:500, w / w) into which sugar beet (B. vulgaris) seeds were planted in the greenhouse; seeds planted in noninfested soil were used as controls. Damping-off (80%) occurred only in infested soil. Reisolation of P. salpingophorum from diseased seedlings confirmed pathogenicity. This is the first report of P. salpingophorum as a pathogen of B. vulgaris, although the fungus has been isolated from roots of Ceanothus cyaneus Eastw., Linum usitatissimum L. Lupinus spp., Lycopersicon esculentum Mill., Pisum sativum L., Spinacia oleracea L., and Trifolium incarnatum L.; the fungus was highly virulent in seedlings of Lupinus spp. and T. incarnatum but only weakly pathogenic in other legumes.