Reducing the spread of Phytophthora ramorum on the Redwood Nature Trail, Curry County Oregon: A case study.

Author , ,
Date 2012
Publication 6th IUFRO Meeting Working Party 7-02-09, Phytophthora in Forests and Natural Ecosystems Meeting. September 9 – 14, 2012. Córdoba-Spain.
Key Words
AbstractIn August 2009, a tanoak adjacent to a popular hiking trail was confirmed infected by Phytophthora ramorum. The trail was immediately closed to the public. An eradication treatment consisting of injected herbicide and cutting, piling, and burning tanoaks and other selected hosts in a 100 m radius around the infected tanoak was completed by December 2009. Close to 490 m of trail lies within or on the boundary of the treatment area while approximately 60 m of trail passes through the infested zone. To limit the number of P. ramorum spores in soil and the potential for spore splash dispersal, a 4‐inch thick layer of Thuja plicata heartwood chips was placed on the trail in July 2010. The trail was then reopened to public use. Soil samples were collected at 11 locations on the trail four times prior to chip treatment and three times after chip treatment. Phytophthora ramorum was recovered from at least one of the 11 samples on all sampling occasions except in July 2010 and June 2011. The number of P. ramorum‐positive soil samples was 2/11, 5/11, and 6/11 before‐chip treatment and 1/11 and 1/11 samples after‐chip treatment. All P. ramorum‐positive samples were found within approximately 8 m of the infected tree. P. ramorum’s presence in trail soil appears to have been reduced in the year after chip treatment. Recently, additional P. ramorum infections have been detected near the trail and due to use, chip depth has also been greatly reduced. Additional treatments will be done and monitoring will continue.
Full Citation Goheen, E.M.; Reeser, P.; and Sutton, W. Reducing the spread of Phytophthora ramorum on the Redwood Nature Trail, Curry County Oregon: A case study. Poster 22. 6th IUFRO Meeting Working Party 7-02-09, Phytophthora in Forests and Natural Ecosystems Meeting. September 9 – 14, 2012. Córdoba-Spain.