Geographical distribution of Phytophthora ramorum in Norway

Abstract

In November 2002, Phytophthora ramorum was detected for the first time in Norway. It was isolated from Rhododendron catawbiense imported earlier the same year. After the first detection, the Norwegian Food Safety Authority has carried out surveys from 2003 to 2006. The surveys were first directed to nurseries and garden centres. Most of the positive findings were on Rhododendron spp., but one sample of Pieris japonica, one of Kalmia sp., one of Syringa sp. and one of Viburnum sp. were also positive. In 2005 and 2006, P. ramorum was isolated from well-established viburnum and rhododendron plants in private gardens, parks and public greens. Infections were detected on well-established plants from nine different outdoor sites. While the positive samples from nurseries were spread over the country, the positives found on well-established plants were concentrated in and around the cities of Bergen and Stavanger on the southwestern coast of Norway. This part of the country has cool summers, mild winters and more than 2000 mm of annual precipitation. In 2006, P. ramorum was found in private gardens in the eastern part of the country on young recently introduced plants. P. ramorum was found in 12 import shipments, mainly on rhododendron, but also on a viburnum sample.

Parent Publication

• Proceedings of the sudden oak death third science symposium

Citation

Herrero, María- Luz ; Toppe, Brita; Rafoss, Trond. 2008. Geographical distribution of Phytophthora ramorum in Norway. 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. p. 373