@article {EFP:EFP711, title = {A twig blight of understorey European beech (Fagus sylvatica) caused by soilborne Phytophthora spp.}, journal = {Forest Pathology}, volume = {41}, number = {6}, year = {2011}, pages = {493{\textendash}500}, publisher = {Blackwell Publishing Ltd}, abstract = {

During and after prolonged periods of rainfall in late spring, blighted young twigs of European beech (Fagus sylvatica) were frequently observed in several beech stands in south-western and southern Germany. Long and short shoots of young understorey trees or lower branches up to 1.5 m above the soil level were affected. Symptoms also occurred regularly on twigs in heights up to 2 m and more above the ground. Necroses usually expanded within the current year{\textquoteright}s tissue and often also reached into the previous year{\textquoteright}s wood. Ponding rain water in the stands or along forest roads or open soil seemed to promote the disease. Of a total of 54 symptomatic twigs collected in four stands, 37 revealed Phytophthora isolates, of which 33 were P. plurivora and four were P. cambivora. Both species caused extensive lesions on beech twigs in laboratory pathogenicity tests. Patterns of the disease indicated that these pathogens, generally considered soilborne species, in most cases are transmitted from the soil to above-ground parts of the trees via rain splash. In larger heights, however, other vectors such as snails might be responsible for transmission. Although Phytophthora spp. are well known as causal agents of seedling blight as well as root and cambium rot and aerial bleeding cankers of mature beech, to our knowledge this is the first report of a twig blight in beech associated with soilborne Phytophthora spp. In particular in periods of high precipitation, this disease might pose an additional threat to Central European beech forests, especially endangering the success of artificial and natural regeneration of beech in affected stands.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00711.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00711.x}, author = {Nechwatal, J. and Hahn, J. and Schönborn, A. and Schmitz, G.} } @article {3978, title = {A combination of baiting and PCR techniques for the detection of Phytophthora quercina and P. citricola in soil samples from oak stands}, journal = {Forest Pathology}, volume = {31}, year = {2001}, pages = {85-97}, abstract = {

Es wird der spezifische Nachweis von Phytophthora quercina und P. citricola in Bodenproben von absterbenden Eichen mit Hilfe einer Kombination von PCR- Reaktionen mit artspezifischen Primern erlaubten den Nachweis von P. quercina und P. citricola in den infizierten Eichenblaettern aus diesen Tests und im jeweiligen {\textquoteright}Baiting-Wasser{\textquoteright}. Der PCR- und Baiting-Methoden beschrieben. Die Bodenproben wurden mit Wasser geflutet und Baiting-Tests unterzogen, bei denen junge Blaettchen von Quercus robur als Koeder zum Einsatz kamen. Einfache oder nested PCR-Nachweis beider Erreger war auch moeglich, wenn Bodenproben gruendlich mit Wasser gemischt wurden, das aufgeschwemmte organische Material abgesammelt und das Wasser abgenommen wurde. P. quercina und P. citricola wurden dabei in nahezu allen Faellen im Wasser, jedoch weniger regelmaessig im organischen Material nachgewiesen. Die Identitaet der betreffenden Arten wurde zusaetzlich durch Restriktions-Analysen der entsprechenden Amplicons bestaetigt. Ausserdem wurde die Anwesenheit beider Arten in den untersuchten Bodenproben durch klassische Baiting-Methoden nachgewiesen. Nested PCR mit den verwendeten Primaerpaaren erlaubte den Nachweis von nur 5 Zoosporen von P. citricola und 300 Zoosporen von P. quercina in einem Gesamt-Volumen von 100 My l. Die beschriebenen Methoden ermoeglichen Nachweis und Identifizierung von Phytophthora-Arten in Bodenproben, ohne die Notwendigkeit einer direkten Extraktion des Bodens und ohne weitreichende Kenntnis der morphologischen Merkmale der Arten dieser Gattung.

}, issn = {1437-4781}, author = {Nechwatal, J. and Schlenzig, A. and T. Jung and Cooke, D. E. L. and Duncan, J. M. and W. O{\ss}wald} } @article {PPA:PPA2638, title = {The morphology, behaviour and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov.}, journal = {Plant Pathology}, year = {2012}, month = {04/2013}, pages = {355{\textendash}369}, publisher = {Blackwell Publishing Ltd}, abstract = {

Since its first isolation from Salix roots in 1972, isolates of a sexually sterile Phytophthora species have been obtained frequently from wet or riparian habitats worldwide and have also been isolated from roots of Alnus and Prunus spp. Although originally assigned to Phytophthora gonapodyides on morphological grounds, it was recognized that these isolates, informally named P.\ taxon Salixsoil, might represent a separate lineage within ITS Clade 6. Based on phylogenetic analyses and comparisons of morphology, growth-temperature relationships and pathogenicity, this taxon is formally described here as Phytophthora lacustris sp. nov. Isolates of P.\ lacustris form a clearly resolved cluster in both ITS and mitochondrial cox1 phylogenies, basal to most other Clade 6 taxa. Phytophthora lacustris shares several unusual behavioural properties with other aquatic Clade 6 species, such as sexual sterility and tolerance of high temperatures, that have been suggested as adaptations to riparian conditions. It appears to be widespread in Europe and has also been detected in Australia, New Zealand and the USA. It was shown to be weakly or moderately aggressive on inoculation to Alnus, Prunus and Salix. The extent of P.\ lacustris{\textquoteright} activity as a saprotroph in plant debris in water and as an opportunistic pathogen in riparian habitats needs further investigation. Its pathogenic potential to cultivated fruit trees also deserves attention because P.\ lacustris has apparently been introduced into the nursery trade.

}, keywords = {Alnus, phylogeny, Phytophthora ITS Clade 6, Prunus, riparian habitat, tree pathogen}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02638.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02638.x}, author = {Nechwatal, J. and Bakonyi, J. and Cacciola, S. O. and Cooke, D. E. L. and T. Jung and Nagy, Z. {\'A}. and Vannini, {\'A}. and A.M. Vettraino and C.M. Brasier} }