@article {3964, title = {Re-evaluation of Phytophthora citricola isolates from multiple woody hosts in Europe and North America reveals a new species, Phytophthora plurivora sp. nov.}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {22}, year = {2009}, month = {06/2009}, pages = {95 - 110}, abstract = {

During large-scale surveys for soilborne Phytophthora species in forests and semi-natural stands and nurseries in Europe during the last decade, homothallic Phytophthora isolates with paragynous antheridia, semipapillate persistent sporangia and a growth optimum around 25 {\textdegree}C which did not form catenulate hyphal swellings, were recovered from 39 host species in 16 families. Based on their morphological and physiological characters and the similarity of their ITS DNA sequences with P. citricola as designated on GenBank, these isolates were routinely identified as P. citricola. In this study DNA sequence data from the internal transcribed spacer regions (ITS1 and ITS2) and 5.8S gene of the rRNA operon, the mitochondrial cox1 and β-tubulin genes were used in combination with morphological and physiological characteristics to characterise these isolates and compare them to the ex-type and the authentic type isolates of P. citricola, and two other taxa of the P. citricola complex, P. citricola I and the recently described P. multivora. Due to their unique combination of morphological, physiological and molecular characters these semipapillate homothallic isolates are described here as a new species, P. plurivora sp. nov.

}, keywords = {Beech, citricola, Decline, dieback, forest, multivora, nursery, oak, phylogeny}, issn = {00315850}, doi = {10.3767/003158509X442612}, author = {T. Jung and Burgess, T. I.} } @article {3997, title = {New insights into the survival strategy of the invasive soilborne pathogen Phytophthora cinnamomi in different natural ecosystems in Western Australia}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {08/2013}, pages = {266{\textendash}288}, abstract = {

Despite its importance as one of the most notorious, globally distributed, multihost plant pathogens, knowledge on the survival strategy of Phytophthora cinnamomi in seasonally dry climates is limited. Soil and fine roots were collected from the rhizosphere of severely declining or recently dead specimens of 13 woody species at 11 dieback sites and two dieback spots and from healthy specimens of five woody species at four dieback-free sites in native forests, woodlands and heathlands of the south-west of Western Australia (WA). Phytophthora cinnamomi was recovered from 80.4, 78.1 and 100\% of tested soil, fine root and soil{\textendash}debris slurry samples at the 11 dieback sites, in some cases even after 18-month storage under air-dry conditions, but not from the small dieback spots and the healthy sites. Direct isolations from soil{\textendash}debris slurry showed that P. cinnamomi colonies exclusively originated from fine roots and root fragments not from free propa- gules in the soil. Microscopic investigation of P. cinnamomi-infected fine and small woody roots and root fragments demonstrated in 68.8, 81.3 and 93.8\% of samples from nine woody species the presence of thick-walled oospores, stromata-like hyphal aggregations and intracellular hyphae encased by lignitubers, respectively, while thin-walled putative chlamydospores were found in only 21.2\% of samples from five woody species. These findings were confirmed by microscopic examination of fine roots from artificially inoculated young trees of 10 woody species. It is suggested that (i) the main function of chlamydospores is the survival in moderately dry conditions between consecutive rain events and (ii) selfed oospores, hyphal aggregations, and encased hyphae and vesicles in infected root tissue of both host and non-host species are the major long-term survival propagules of P. cinnamomi during the extremely dry summer conditions in WA.

}, doi = {10.1111/efp.12025}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12025/abstract}, author = {T. Jung and Colquhoun, I. J. and Hardy, G. E. St. J.}, editor = {S. Woodward} } @article {JUNG2005159, title = {Involvement of Phytophthora species in the decline of European beech in Europe and the USA}, journal = {Mycologist}, volume = {19}, number = {4}, year = {2005}, pages = {159 - 166}, keywords = {detection}, issn = {0269-915X}, doi = {DOI: 10.1017/S0269-915X(05)00405-2}, url = {http://www.sciencedirect.com/science/article/B7XMS-4R10WR2-5/2/37dcb413ca17af3b17f99e6101570c65}, author = {T. Jung and G. W. Hudler and S.L. Jensen-Tracy and H.M. Griffiths and F. Fleischmann and W. Osswald} } @article {3976, title = {Phytophthora quercina sp. nov., causing root rot of European oaks}, journal = {Mycological Research}, volume = {103}, year = {1999}, month = {7/1999}, pages = {785 - 798}, abstract = {

In a 3 year study of oak (Quercus robur, Q. petraea, Q. cerris, Q. pubescens and Q. ilex) decline in Central and Southern Europe, a papillate homothallic Phytophthora species was isolated consistently, with other Phytophthora spp., from necrotic fine roots by direct plating on to selective agar medium and from rhizosphere soil samples by baiting with leaves of Quercus robur. The morphology, physiology, RAPD banding patterns and pathogenicity against apple fruits of this Phytophthora sp. are described and compared with those of other papillate Phytophthora species from Waterhouse{\textquoteright}s Group I, namely P. cactorum, P. clandestina, P. idaei, P. iranica, P. pseudotsugae and P. tentaculata, and papillate Group III P. citricola. The papillate Phytophthora isolates from oak differed from all other Group I species by their uniform, dome-shaped and cottonwool-like colony growth pattern on V8 juice agar and malt extract agar, the frequent occurrence of sympodially branched primary hyphae, a high proportion of elongated, ellipsoid or ovoid oogonia, the absence of amphigynous antheridia and RAPD banding patterns. Additionally, there was no other species in Group I with as much variation in size and shape of the sporangia or large proportion of sporangia with a curved apex, hyphal projections, lateral displacement of the papilla and lateral attachment to the sporangiophore. In pathogenicity tests with infested soil, the isolates proved to be more pathogenic to Q. robur than any other Phytophthora sp. recovered from declining oaks in Central Europe. Based on their unique combination of cultural, sporangial and gametangial morphology, pathogenicity and close association with Quercus but not other trees, the papillate Phytophthora isolates from oak are described as Phytophthora quercina sp. nov.

}, issn = {09537562}, doi = {10.1017/S0953756298007734}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208606115}, author = {T. Jung and Cooke, D. E. L. and Blaschke, H. and Duncan, J. M. and W. O{\ss}wald} } @article {1294133220040401, title = {Phytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies.}, journal = {Plant Pathology}, volume = {53}, number = {2}, year = {2004}, pages = {197 - 208}, abstract = {

A survey of symptoms of phytophthora root and collar rot of common (Alnus glutinosa) and grey alder (A. incana) in riparian and forest stands in Bavaria was conducted by the Bavarian State Forestry and river authorities. Symptoms were seen in 1041 out of 3247 forest alder stands. The majority of the affected stands (80{\textperiodcentered}9\%) were less than 21 years old; 46\% of these young stands were growing on nonflooded sites and 92\% had been planted. The riparian survey showed that symptoms were widespread along more than 50\% of the river systems. Along some rivers the disease incidence exceeded 50\%. The {\textquoteleft}alder Phytophthora{\textquoteright} was recovered from 166 of 185 riparian and forest alder stands with symptoms. In 58 of the 60 rivers and streams investigated in detail, the source of inoculum was traced back to infested young alder plantations growing on the river banks or on forest sites that drain into the rivers. Once introduced to a river system, the {\textquoteleft}alder Phytophthora{\textquoteright} infects alders downstream. Baiting tests showed that the {\textquoteleft}alder Phytophthora{\textquoteright} was present in rootstocks of alders from three out of four nurseries which regularly bought in alder plants for re-sale, but not in rootstocks from four nurseries that grew their own alders from seed. In addition, the infected nurseries used water from infested water courses for irrigation. The Bavarian State Ministry for Agriculture and Forestry has developed a code of practice for producing healthy alder plants in forest nurseries. This includes a 3-year fallow period between bare-rooted alder crops because of poor survival of the {\textquoteleft}alder Phytophthora{\textquoteright} in soil.

}, keywords = {ALDER {\textendash} Diseases \& pests, Alnus, Bavaria, diseases, fungal diseases of plants, GERMANY, nursery, pathway, Phytophthora, plantation, riparian areas}, issn = {00320862}, doi = {10.1111/j.0032-0862.2004.00957.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.0032-0862.2004.00957.x/abstract}, author = {T. Jung and Blaschke, M.} } @article {3974, title = {Involvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease}, journal = {Plant Pathology}, volume = {49}, year = {2000}, month = {12/2000}, pages = {706 - 718}, abstract = {

A survey was made on the occurrence of soilborne Phytophthora species in 35 oak stands on a range of geologically different sites in Bavaria. The most widespread species were P. quercina, P. cambivora and P. citricola. Seven other Phytophthora species were isolated infrequently. The fine root systems of 106 healthy and 111 declining mature trees of Quercus robur and Q. petraea were intensively investigated. The results indicate that, depending on the site conditions, at least two different complex diseases are referred to under the name {\textquoteleft}oak decline{\textquoteright}. On sites with a mean soil pH (CaCl2) 3{\textperiodcentered}5 and sandy-loamy to clayey soil texture Phytophthora spp. were commonly isolated from rhizosphere soil, and highly significant correlations existed between crown transparency and various root parameters. Oaks with P. quercina or other Phytophthora spp. in their rhizosphere had markedly higher levels of fine root damage than oaks without Phytophthora spp., and were subject to a relative risk of severe crown symptoms of 2{\textperiodcentered}1 and 2{\textperiodcentered}8, respectively. In contrast, in stands with sandy to sandy-loamy soils and a mean soil pH\  3{\textperiodcentered}9, Phytophthora spp. were not found. In these stands, correlations between crown transparency and various root parameters were either less significant or not significant. It is concluded that Phytophthora species are strongly involved in oak decline on sandy-loamy to clayey sites with a mean soil-pH (CaCl2).

}, issn = {0032-0862}, doi = {10.1046/j.1365-3059.2000.00521.x}, author = {T. Jung and Blaschke, H. and W. O{\ss}wald} } @article {Jung:2011:0031-5850:13, title = {Multiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {26}, number = {1}, year = {2011}, pages = {13-39}, abstract = {

During surveys of dying vegetation in natural ecosystems and associated waterways in Australia many new taxa have been identified from Phytophthora ITS Clade 6. For representative isolates, the region spanning the internal transcribed spacer region of the ribosomal DNA, the nuclear gene encoding heat shock protein 90 and the mitochondrial cox 1 gene were PCR amplified and sequenced. Based on phylogenetic analysis and morphological and physiological comparison, four species and one informally designated taxon have been described; Phytophthora gibbosa, P. gregata, P. litoralis, P. thermophila and P. taxon paludosa. Phytophthora gibbosa, P. gregata and P. taxon paludosa form a new cluster and share a common ancestor; they are homothallic and generally associated with dying vegetation in swampy or water-logged areas. Phytophthora thermophila and P. litoralis are sister species to each other and more distantly to P. gonapodyides. Both new species are common in waterways and cause scat tered mortality within native vegetation. They are self-sterile and appear well adapted for survival in an aquatic environment and inundated soils, filling the niche occupied by P. gonapodyides and P. taxon salixsoil in the northern hemisphere. Currently the origin of these new taxa, their pathogenicity and their role in natural ecosystems are unknown. Following the precautionary principle, they should be regarded as a potential threat to native ecosystems and managed to minimise their further spread.

}, doi = {doi:10.3767/003158511X557577}, url = {http://www.ingentaconnect.com/content/nhn/pimj/2011/00000026/00000001/art00002}, author = {T. Jung and Stukely, M. J. C. and Hardy, G.E.S.t.J. and White, D. and Paap, T. and Dunstan, W.A. and Burgess, T. I.} } @article {3965, title = {Beech decline in Central Europe driven by the interaction between Phytophthora infections and climatic extremes}, journal = {Forest Pathology}, volume = {39}, year = {2009}, month = {04/2009}, pages = {73 - 94}, abstract = {

During the past decade, and in particular after the wet year 2002 and the dry year 2003, an increasing number of trees and stands of European beech (Fagus sylvatica L.) in Bavaria were showing symptoms typical for Phytophthora diseases: increased transparency and crown dieback, small-sized and often yellowish foliage, root and collar rot and aerial bleeding cankers up to stem heights of \>20\ m. Between 2003 and 2007 134 mature beech stands on a broad range of geological substrates were surveyed, and collar rot and aerial bleeding cankers were found in 116 (86.6\%) stands. In most stands the majority of beech trees were declining and scattered or clustered mortality occurred. Bark and soil samples were taken from 314 trees in 112 stands, and 11 Phytophthora species were recovered from 253 trees (80.6\%) in 104 stands (92.9\%). The most frequent species were P. citricola, P. cambivora and P. cactorum. Primary Phytophthora lesions were soon infected by a series of secondary bark pathogens, including Nectria coccinea, and wood decay fungi. In addition, infected trees were often attacked by several bark and wood boring insects leading to rapid mortality. Bark necroses were examined for their probable age in order to determine whether the onset of the current Phytophthora epidemic was correlated to rainfall rates recorded at 22 Bavarian forest ecosystem monitoring stations. A small-scale survey in nine Bavarian nurseries demonstrated regular infestations of all beech fields with the same range of Phytophthora species. The results indicate that (1) Phytophthora species are regularly associated with beech decline and may also be involved in the complex of {\textquoteleft}Beech Bark Disease{\textquoteright}, (2) excessive rainfalls and droughts are triggering the disease, and (3) widespread Phytophthora infestations of nursery stock might endanger current and future silvicultural projects aiming on the replacement of non-natural conifer stands by beech dominated mixed stands.

}, issn = {14374781}, doi = {10.1111/j.1439-0329.2008.00566.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.2009.39.issue-2/issuetoc}, author = {T. Jung} }