Blight of Prostrate Spurge and Cultivated Poinsettia Caused by Amphobotrys ricini. G. E. Holcomb, Professor, Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge 70803. J. P. Jones, and D. W. Wells. Associate Professor, Department of Plant Pathology and Crop Physiology, and Instructor, Hammond Research Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. Plant Dis. 73:74-75. Accepted for publication 23 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0074.

The fungus Amphobotrys ricini was isolated from blighted leaves and stems of prostrate spurge and cultivated poinsettia. Laboratory and greenhouse pathogenicity tests were positive on Euphorbia supina (prostrate spurge), E. pulcherrima (cultivated poinsettia), E. heterophylla (wild poinsettia), E. hirta (garden spurge), and Ricinus cummunis (castor bean). This is the first report of blight of prostrate spurge and cultivated poinsettia caused by A. ricini in the United States.

Keyword(s): Botryotinia ricini, fungal diseases of plants.