MSA - Ecology/Pathology
Adams, Gerard , Catal, Mursel , Trummer, Lori .
Widespread distribution of Phytophthora alni ssp. uniformis in Alaska.
Dieback and mortality in grey alders (Alnus incana ssp. tenuifolia) have become widespread in Alaska, recently. In Europe, a similar disease situation has been occurring in A. incana and A. glutinosa stands that has been attributed to root and collar rot by subspecies of P. alni. In 2007, our lab discovered P. alni in Alaska: the first report of this pathogenic species in North America. The occurrence of P. alni was of concern, and previously the USDA Forest Health Technology Enterprise Team had developed a model assessing the risk of introduction, spread, and establishment of the pathogen in the United States. Therefore, a more extensive sampling of alder stands was initiated in southcentral and interior Alaska to determine if the species was restricted to the locations of original discovery, and whether it was moving along specific water courses. Rhizosphere soils from alder stands and watercourses were baited with rhododendron leaves to trap Phytophthora species. After incubation leaves were washed and shipped to the laboratory for isolation on selective media. Isolates were subcultured for DNA extraction, amplification of ITS, and identification by sequencing. Thirty two isolates of P. alni ssp. uniformis were collected from 11 geographically distributed stands. Only one isolate was obtained from bait floating in a water course, the Tanana River, out of 81 watercourses sampled. Soil isolates were from four plots in southcentral Alaska along the Kenai and Russian Rivers and seven plots in the interior, including a plot in Fairbanks, three plots between Delta Junction and Fairbanks along Hwy 2, two between Slana and Tok along Hwy 1, and one near Denali National park on Hwy 3. The species is widely distributed and difficult to isolate.
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1 - Michigan State University, Plant Pathology , 107 CIPS building, East Lansing, MI, 48824, USA
2 - United States Forest Service, Forest Health Protection, Alaska Region, 3301 C Street, Suite 202, Anchorage, AK, 99503, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM