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Disease Note.

Apios americana and Trillium foetidissimum as New Hosts of Sclerotinia sclerotiorum. G. E. Holcomb, Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. . Plant Dis. 74:720. Accepted for publication 24 May 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0720B.

A blight was observed on leaves and stems of Trillium foetidissimum Freeman (wake robin, red trillium), a common woodland wildflower in southeastern Louisiana. Blight progressed from leaves to stems, and signs of the fungal pathogen were often present in the form of white mycelia and black sclerotia. The disease on Apios americana Medik. (groundnut), a native American plant currently being investigated for possible domestication (1), was a soft, nonwatery storage rot of tubers. Signs of the fungal pathogen were also present in the form of white mycelia and black sclerotia. Fungal isolates (isolated on 2% water agar and maintained on potato-dextrose agar) from both plant species were pathogenic to their respective hosts, and the fungi were reisolated from inoculated plants. Reciprocal host inoculations were not performed with the fungal isolates. The fungi from A. americana and T. foetidissimum were identified as Sclerotinia sclerotiorum (Lib.) de Bary based on cultural characteristics using Kohn's (2) key to the plant-pathogenic species of Sclerotinia. This is the first report of the occurrence of S. sclerotiorum on either of these plant species.

References: (1) W. J. Blackmon and B. D. Reynolds. HortScience 21:1334, 1986. (2) L. M. Kohn. Phytopathology 69:881, 1979.