Skip to Main Content
Detecting Phytophthora ramorum and other species of Phytophthora in Streams in natural ecosystems using baiting and filtration methodsAuthor(s): Jaesoon Hwang; Steven W. Oak; Steven Jeffers
Source: 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. 4
Publication Series: General Technical Report (GTR)
Station: Pacific Southwest Research Station
PDF: View PDF (502 KB)
DescriptionPhytophthora spp. occur widely in forest and other natural ecosystems. Because these straminipiles are well adapted to aquatic environments, monitoring strategically selected streams may reflect occurrence and distribution of Phytophthora spp. over the relatively large area drained by these streams. The mountain region of western North Carolina, in the southern Appalachian Mountains, was designated as a high risk area for sudden oak death, caused by P. ramorum, based on the occurrence of numerous native host plants, a relatively mild climate, and the prevalence of nursery businesses in this region that import plants or plant material from areas known to be infested. Therefore, five streams in three watersheds in Pisgah National Forest in western North Carolina were sampled monthly for Phytophthora spp. from April 2005 to March 2006 to determine if P. ramorum was present in the region, to determine the diversity of species of Phytophthora native to the region, and to compare baiting and filtration as detection methods. For baiting, either four wounded or four nonwounded leaves of Rhododendron maximum (a plant native to this region) were placed in a mesh bait bag made with nylon screen and PVC pipe (fig. 1). Wounded leaves were floated in a stream for 3 days while non-wounded leaves were exposed for 2 to 3 weeks. Water soaked lesions had developed on wounded leaves after 3 days in the water, and dark brown necrotic lesions were observed on non-wounded leaves exposed for 2 to 3 weeks. In the laboratory, five pieces of symptomatic leaf tissue were taken from each leaf, a total of 40 leaf pieces were embedded in PARPH-V8 selective medium to isolate Phytophthora spp. for each stream. For filtration, one liter of water was collected from each stream, and samples were filtered within 10 hours of collection. Nine 100-ml subsamples of water were vacuum-filtered (fig. 2) through two types of membrane filters (47-mm in diameter) with three pore sizes (Nuclepore with 1- and 3-μm pores and Durapore with 5-μm pores), and filters were inverted on PARPHV8 medium to recover propagules of Phytophthora spp. trapped on the filters (fig. 3).
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationHwang, Jaesoon; Oak, Steven W.; Jeffers, Steven. 2008. Detecting Phytophthora ramorum and other species of Phytophthora in Streams in natural ecosystems using baiting and filtration methods. 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. 4
KeywordsDiversity, forest streams, detection, membrane filter, Rhododendron maximum
- Monitoring occurrence and distribution of Phytophthora species in forest streams in North Carolina using bait and filtration methods
- Conditions 10 years after sudden oak death suppression treatments in Humboldt County, California
- Arkansas, 2009 forest inventory and analysis factsheet
XML: View XML