Kartlegging av Phytophthora i vann og vassdrag i og rundt byer og tettsteder på Sunnmøre

Abstract

This Phytophthora-survey was mainly carried out by baiting with leaves from Rhododendron ´Cunninghams White´ in ponds, rivers and lakes in 4 municipalities in the area of Sunnmøre, in northwestern Norway. No such studies have previously taken place in this area before. In addition to baiting, a soil sample and samples from symptomatic trees were analyzed for Phytophthora. Selected isolates were sequenced using Internal Transcribed Spacer (ITS) regions. A total of 6 species of Phytophthora and one species from the genus Halophytophthora, were found. The Phytophthora species were P. gonapodyides, P. plurivora, P. riparia, P. taxon PgChlamydo, P. cambivora and a not yet identified species of Phytophthora preliminary was named Phytophthora sp. Ørsta after the municipality where it was found. P. cambivora was only isolated from stem tissue from a copper beech (Fagus sylvatica ´Atropunicea´), not by baiting. The Halophytophthora species was also an unknown species (no match in the GenBank). It was found in brackish water in Ålesund municipality. Further studies of the Halophytophthora sp. were not a part of this thesis. In Ålesund municipality, baiting was carried out 3 times during the season, in June, August and October 2013. In the remaining municipalities, Ulstein, Herøy and Ørsta, fewer baits were used and baiting was only performed in August 2013. Phytophthora was isolated from 17 of 20 locations in Ålesund municipality, which represents 85 % of the sites. There P. gonapodyides, P. plurivora, P. riparia, P. taxon PgChlamydo, P. cambivora and Halophytophthora sp. were found. In Ulstein and Herøy municipalites, only P. gonapodyides was found. In Ørsta, P. gonapodyides and the yet unknown species Phytophthora sp. Ørsta were detected.