Spread and development of Phytophthora ramorum in a California christmas tree farm

Abstract

The risk of conifers being infected by Phytophthora ramorum under natural conditions is poorly understood. In California, infected conifers commonly occur as understory plants beneath or adjacent to heavily infected plants like California bay laurel (Umbellularia californica). During wet periods, P. ramorum is known to produce a copious amount of spores from spots on infected leaves of this epidemiologically-important host. In Oregon, infection on California bay laurel is limited and infection of Douglas-fir (Pseudotsuga menziesii) trees has been limited to a few seedlings directly beneath infected tanoak (Lithocarpus densiflorus) trees in the regulated area in Curry County.

Parent Publication

• Proceedings of the sudden oak death third science symposium

Citation

Chastagner, Gary A.; Riley, Kathy; Dart, Norm. 2008. Spread and development of Phytophthora ramorum in a California christmas tree farm. In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M., tech. coords. 2008. Proceedings of the sudden oak death third science symposium. Gen. Tech. Rep. PSW-GTR-214. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 199-200