APS Abstracts of Presentations

Susceptibility of Vaccinium to Phytophthora ramorum, cause of sudden oak death. J. L. PARKE (1), R. G. Linderman (2), and E. M. Hansen (1). (1) Dept. of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331; (2) USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR 97330. Phytopathology 92:S63. Publication no. P-2002-0456-AMA.

Phytophthora ramorum, cause of sudden oak death in California and Oregon, also causes foliar infection and dieback on several understory species including evergreen huckleberry (Vaccinium ovatum). The susceptibility of other wild Vaccinium species and of horticulturally important Vaccinium crops such as blueberry, cranberry, and lingonberry was tested in detached leaf assays using mycelial plugs or zoospore inoculum of P. ramorum. Disease severity was compared to that resulting from leaf inoculation of known hosts (tanoak, bay, evergreen huckleberry, rhododendron, madrone). A wide range of disease responses was observed among the Vaccinium species, from resistant (cranberry) to highly susceptible (lingonberry). The 20 blueberry cultivars tested also differed significantly in their response to the pathogen. Sporulation of the pathogen on excised leaf disks differed among plant species and cultivars, allowing quantification of the reproductive potential on each host.

Copyright 2002 by The American Phytopathological Society. All rights reserved.