摘要：Phytophthora-disease of alders in Vienna
Monitoring results of Common alder (Alnus glutinosa)
and Grey alder stands (Alnus incana) conducted in the
area of Vienna, Austria, are presented. The aim of the
project, which was commissioned by the Municipality of
the City of Vienna (Municipal Department 45 - Water
Engineering) was – besides a primary inventory of alder
stands in Vienna - the assessment of the Phytophthoradisease
along waterways in the Viennese woods.
The densest stands of alders (mainly Common alder) were
found along the underflow of several streams consisting of
trees older than thirty years and of natural regeneration.
Most of the stands were healthy, but some showed trees
suffering from or killed by drought stress (mainly following
summer 2003). On some sites, however, Phytophthora
was identified as a cause for dieback.
The following Phytophthora species were recorded on
alders in the area of Vienna: Phytophthora alni spp. alni, P.
alni spp. multiformis and P. citricola. Of those, spp. alni
had led to serious decline and dieback of alders. The
occurrence of P. alni was mainly related to planting of
alders infested with the pathogen from the roots. In one
case the pathogen was probably swept down with river
water from areas in Lower Austria.
From those findings, it can be concluded, that the highest
risk of a spread of the Phytophthora-disease into Vienna’s
alder stands is the introduction of infested plant material
into the upper parts of the streams.
关键词：Phytophthora, Common alder, Grey alder, Austria,
disease intensity
