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Plant Pathology

Department of Plant Pathology


Sudden Oak Death: mechanisms of oak resistance to Phytophthora ramorum

The tree pathogen Phytophthora ramorum is an aggressive, apparently introduced fungal-like organism (oomycete) that causes sudden oak death (SOD). SOD has played a significant role in shaping the dynamics of the mixed evergreen forests of coastal California and southwestern Oregon, and, more recently, larch stands in the British Isles. P. ramorum has an extensive host range and is a significant threat to both the landscape and nursery industry in North America and Europe.

Our research objectives are to understand mechanisms of oak resistance to P. ramorum infection and to develop methods for predicting resistance within natural populations. The identification of field resistant oak will allow us to protect valuable trees from pre-emptive eradication efforts and urban development, and provide valuable genetic material for breeding of resistant tree stock.

This project is in collaboration with Dr. David Wood and Dr. Brice McPherson at the University California, Berkeley.

For an overview of the disease see our article in City Trees, a publication of the Journal of the Society of Municipal Arborists:

Conrad, A.O., Bonello, P., and Bienemann, D.S. An introduction to sudden oak death and upcoming research. City Trees September/October 2011.