Poster Abstract
  Pathogenicity and Resistance

Plant Species Naturally Infected by Phytophthora ramorum in Oregon Forests

E. Goheen¹, E. Hansen², A. Kanaskie³, M. McWilliams³, N. Osterbauer⁴, and W. Sutton⁵

Phytophthora ramorum was found in July 2001 near Brookings Oregon, killing tanoak (Lithocarpus densiflorus) and causing dieback of closely associated wild rhododendron and evergreen huckleberry. Subsequent examinations have found a few more plant species naturally infected, but despite intensive surveys in areas of infection, and the presence of many species known to be susceptible in artificial inoculation, the list remains much shorter than in California, and in most cases, disease incidence is very low. The Oregon list includes: tanoak, wild rhododendron (R. macrophylum), evergreen huckleberry (Vaccinium ovatum) poison oak (Rhus diversiloba), cascara (Rhamnus purshiana), and salmon berry (Rubus spectabilis). Symptoms from natural infection and artificial inoculation are illustrated, and field disease incidence is recorded.

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¹USDA Forest Service, SW Oregon Insect and Disease Service Center, Central Point, OR 97502
²Oregon State University, Dept. Botany and Plant Pathology, Corvallis, OR 97331; (541) 737-5243; hansene@bcc.orst.edu
³Oregon Dept. Forestry
⁴Oregon Dept. Agriculture, Salem, OR 97310
⁵Oregon State University, Dept. Botany and Plant Pathology, Corvallis, OR 97331