@proceedings {960, title = {Wildland management of Phytophthora ramorum in northern California forests}, volume = {Gen. Tech. Rep. PSW-GTR-214}, year = {2008}, pages = {305-312}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Rosa, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr214/}, author = {Valachovic, Y. and C. Lee and J. Marshall and H. Scanlon}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @proceedings {961, title = {Forest treatment strategies for Phytophthora ramorum}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2010}, pages = {239-248}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Rosa, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Valachovic, Y. and C. Lee, J. Marshall and H. Scanlon}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @article {4234, title = {Discovery of a fourth evolutionary lineage of Phytophthora ramorum: EU2}, journal = {Fungal Biology}, volume = {116}, year = {2012}, month = {Jan-11-2012}, pages = {1178 - 1191}, abstract = {

Phytophthora ramorum is a recently introduced, aggressive Phytophthora species that has caused extensive mortality of oak and tanoak trees in the western USA and Japanese larch trees in the UK. P. ramorum is also present on Rhododendron, Camellia, and Viburnum in the nursery industry, which is thought to have been the pathway for its spread into new geographic regions including forests and natural ecosystems. Three lineages of P. ramorum have been described, informally designated EU1, NA1, and NA2, and each lineage is believed to originate from an as yet unknown exotic centre of origin. Preliminary SSR and sequence analysis of isolates from a UK P. ramorum survey revealed seven isolates with profiles that did not match the previously known lineages. Detailed SSR and multilocus sequence analysis of these isolates are presented, allowing us to assign these isolates to a new P. ramorum lineage, designated EU2. Although the known geographical origin of these isolates is currently limited to Northern Ireland and western Scotland, the EU2 lineage isolates have been obtained from four different host plants, including Japanese larch. All isolates are of A1 compatibility type, which implies that this finding does not increase the risk of outcrossing with the EU1 lineage isolates already present in the UK. The oldest EU2 strain was isolated in 2007 but no SSR-based intraEU2 lineage genotypic diversity was detected. The combination of these elements points to a recent introduction, despite emergency phytosanitary measures to control introduction and spread. A PCR-RFLP method for the rapid identification of EU2 lineage isolates is presented.

}, issn = {18786146}, doi = {10.1016/j.funbio.2012.09.003}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1878614612001572}, author = {Van Poucke, Kris and Franceschini, Selma and Webber, Joan F. and Vercauteren, Annelies and Turner, Judith A. and McCracken, Alistair R. and Heungens, Kurt and Brasier, Clive M.} } @article {EFP:EFP768, title = {Behaviour and survival of Phytophthora cambivora inoculum in soil-like substrate under different water regimes}, journal = {Forest Pathology}, year = {2012}, pages = {no{\textendash}no}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora cambivora is a soil-borne pathogen responsible for root and collar rot of woody species including Castanea spp., on which it causes Ink disease. P. cambivora does not produce chlamydospores, and the prevalence of a single mating type in nature limits the production of oogonia and oospores. Thus, survival of P. cambivora, in the absence of suitable hosts, relies mainly on sporangia, zoospores and mycelium. However, inoculum survival in soils or substrates represents a major factor in disease epidemics and is probably dependant on environmental factors. The aim of this article was to study the behaviour of P. cambivora in a peat-based substrate (PbS) in the absence of a host, under controlled conditions, and by varying the substrate water regimes. Total inoculum in the substrate was quantified by qPCR, using customized rDNA primer sets, whilst zoospores were quantified after elution, and their vitality was determined by a specific staining procedure. Inoculum infectivity was assessed using chestnut root baits. Results indicated that during the initial 48 h after infestation (matric potential, pF 1.2; 70\% water content), the inoculum level increased producing microsporangia and mycelium before decreasing, regardless of the water regime applied. The number of free zoospores increased over a period of (maximum) 7 days after substrate inoculation. Vitality of zoospores declined to 45\% at day 18, with no statistical differences amongst water regime treatments. Both rDNA and zoospore number increased in flooded samples at day 23, illustrating the vitality of the inoculum. Inoculum was able to infect chestnut root baits up to 45 days at pF 1.2 and 3.5, before and after flooding, but at pF 6.3, only in the absence of flooding. Although based on experiments carried out in microcosms, these results highlight an unexpected resistance of P. cambivora zoospores to environmental constraints. Furthermore, the infectivity ability of the inoculum to survive in PbS over time even in the absence of the host adds relevance to the risk of movement of soil and substrates associated with plant trading worldwide.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2012.00768.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2012.00768.x}, author = {A. Vannini and Breccia, M. and Bruni, N. and Tomassini, A. and A.M. Vettraino} } @article {vannini2001ink, title = {Ink disease in chestnuts: impact on the European chestnut}, journal = {For. Snow Landsc. Res}, volume = {76}, number = {3}, year = {2001}, pages = {345{\textendash}350}, abstract = {A resurgence of ink disease in chestnuts in Europe has been noted since the end of the last century. This lethal disease is currently limiting the establishment of new groves and is threatening the survival of old ones. This paper discusses the impact of the disease and current knowledge about its aetiology and epidemiology. It gives information on the existing variability in tolerance in selected hybrid clones and in wild populations.}, author = {A. Vannini and A.M. Vettraino} } @article {PPA:PPA2585, title = {Alteration of physiological parameters of Austrocedrus chilensis by the pathogen Phytophthora austrocedrae}, journal = {Plant Pathology}, volume = {61}, year = {2012}, pages = {877{\textendash}888}, publisher = {Blackwell Publishing Ltd}, abstract = {

The effect of the pathogen Phytophthora austrocedrae on tree physiology of Austrocedrus chilensis in Patagonia was studied in a 4-week study. In the first week, stem-inoculated saplings showed a significant decrease in photosynthesis (A) without alteration of stomatal conductance (gs) or stem-specific hydraulic conductivity (Ks). From the second week on, progressive decreases in A, gs and Ks were observed, concomitantly with development of significant stem lesions. Water use efficiency (WUE) increased in the second week and declined progressively from the third week. Hyphae and resinous materials were observed in tracheids and rays below lesions. Necrosis of parenchyma ray cells and blockage of tracheids torus were observed. Healthy xylem showed no resinous materials or tracheid blockage, but abundant starch in rays, which was absent in altered xylem. The culture filtrate (CF) of the pathogen was shown to induce changes in extracellular pH and conductivity, and increased necrosis in tissues of leaves and stem challenged with CF in vitro. Similar results were obtained in leaf tissues of the inoculated saplings in vivo. CF injection into xylem of saplings induced a decline in A and disturbance of leaf tissue integrity, without altering gs, WUE or Ks. The decrease of A correlated with changes in tissue integrity. A possible mechanism of A. chilensis decline induced by P. austrocedrae is discussed.

}, keywords = {cypress root rot, effectors, hydraulic conductivity, mal del cipr√{\textcopyright}s, photosynthesis, xylem colonization}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02585.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02585.x}, author = {V{\'e}lez, M. L. and Silva, P. V. and Troncoso, O. A. and Greslebin, A. G.} } @article {PPA:PPA2627, title = {Survival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates}, journal = {Plant Pathology}, volume = {62}, year = {2012}, pages = {166{\textendash}176}, publisher = {Blackwell Publishing Ltd}, abstract = {

This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a novel non-destructive baiting assay from the root balls until at least 8\ months post-inoculation. Plating of surface-sterilized roots and direct microscopic analysis confirmed the presence of P.\ ramorum in the roots. Phytophthora ramorum could also be baited from the root balls of symptomless Rhododendron plants from commercial nurseries, even 2\ years after acquisition. Survival of P.\ ramorum in rootless media was assessed after burying disks of infected leaf material below the soil surface in columns filled with four different undisturbed forest substrates or a potting medium, and incubated at an outdoor quarantine facility. Phytophthora ramorum could be recovered at least 33\ months after burial from all substrates, with a significant increase in recovery after the winter period. These data suggest the possibility for long-term symptomless presence of P.\ ramorum in root balls of commercial Rhododendron plants as well as survival in potting medium and different forest substrates under western European climate conditions. Symptomless presence in root balls can contribute to latent spread of this pathogen between nurseries. The novel baiting test, being non-destructive, simple and applicable to a relatively large number of plants, can offer a valuable tool to test plants for the presence of Phytophthora species in root balls.

}, keywords = {baiting, detection, latent survival, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02627.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02627.x}, author = {Vercauteren, A. and Riedel, M. and Maes, M. and Werres, S. and Heungens, K.} } @article {springerlink:10.1007/s10658-004-1882-0, title = {Occurrence and distribution of Phytophthora; species in European chestnut stands, and their association with Ink Disease and crown decline}, journal = {European Journal of Plant Pathology}, volume = {111}, year = {2005}, note = {10.1007/s10658-004-1882-0}, pages = {169-180}, publisher = {Springer Netherlands}, abstract = {

The Phytophthora complex associated with Castanea sativa Mill. was investigated in five European countries in 35 regions and with respect to various domestication levels. Annual precipitation and length of drought season were the main parameters that regulated the presence of Phytophthora species in the chestnut stands. Seven species of Phytophthora were detected; three of these, P. megasperma, P. cryptogea and P. syringae had not been previously reported on sweet chestnut. P. cinnamomi. P. cambivora and P. citricola were most frequently isolated. P. cinnamomi and P. cambivora were the species significantly associated with declining trees with symptoms of Ink Disease. P. cinnamomi required distinct ecological conditions compared to the other species. P. cinnamomi was never detected in sites characterized by minimum temperatures below 1.4 {\textdegree}C, maximum temperature above 28 {\textdegree}C, or soil pH below 5.4. The results obtained provide useful information for modeling the probability of Ink Disease, crown decline and associated Phytophthora species in chestnut groves in global climatic change scenarios.

}, issn = {0929-1873}, url = {http://dx.doi.org/10.1007/s10658-004-1882-0}, author = {Vettraino, A. and Morel, O. and Perlerou, C. and Robin, C. and Diamandis, S. and A. Vannini} } @article {EFP:EFP264, title = {Occurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees}, journal = {Forest Pathology}, volume = {32}, number = {1}, year = {2002}, pages = {19{\textendash}28}, publisher = {Blackwell Science Ltd.}, abstract = {

Soil-borne species of Phytophthora were isolated from 19 of 30 examined oak forest areas in Italy. The frequency of isolated Phytophthora spp. (35.2\%) was significantly correlated with soil pH and longitude of the sites. Eleven Phytophthora species were detected. Phytophthora cambivora, P. cinnamomi and P. cactorum were recovered from sites in central and southern Italy whereas P. quercina was isolated in the northern and central part of the country. Phytophthora citricola occurred all over Italy. Phytophthora quercina was the only species significantly associated with declining oak trees.

}, issn = {1439-0329}, doi = {10.1046/j.1439-0329.2002.00264.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.2002.00264.x}, author = {A.M. Vettraino and Barzanti, G. P. and Bianco, M. C. and Ragazzi, A. and Capretti, P. and Paoletti, E. and Luisi, N. and Anselmi, N. and A. Vannini} } @article {3966, title = {First report of Phytophthora cactorum associated with beech decline in Italy}, journal = {Plant Disease}, volume = {92}, year = {2008}, month = {12/2008}, pages = {1708 - 1708}, abstract = {

During 2006 and 2007, declining mature beech trees (Fagus sylvatica) were recorded in two stands in the Natural Park of Monti Cimini in central Italy. Symptoms included crown thinning and the presence of bleeding lesions on the main roots and lower stem. Incidence of decline was approximately 5\%. Samples of necrotic bark tissue were collected, cut into 5 mm long segments, plated on PARPNH, and incubated at 20{\textdegree}C (1). Phytophthora isolates were obtained from necrotic tissues of 25\% of the sampled declining trees. Colonies were rosaceous on potato dextrose agar (PDA) and homothallic. Papillate, ovoid-to-obpyriform, caducous sporangia (mean 38 {\texttimes} 26.2 μm) were produced in soil extract. Oospores were plerotic (mean diameter of 22 to 32 μm) and antheridia paragynous. Optimum growth temperature was 23 to 25{\textdegree}C, minimum 6 to 8{\textdegree}C and maximum 30 to 33{\textdegree}C. A portion of the internal transcribed spacer sequence has been deposited in the NCBI database (GenBank Accession No. FJ183724). A BLAST search of the NCBI database revealed Phytophthora cactorum, Accession No. EU194384, as the closest match with 100\% sequence similarity. Pathogenicity of two isolates, PFE3 and IFB-CAC 38, collected from distressed beech trees was tested using a soil infestation test (10 beech seedlings per isolate and control) and an under the bark inoculation method (10 twigs per isolate and controls, wounded and noninoculated taken from a declining beech tree) (2). After 2 weeks at 20{\textdegree}C, twigs and seedlings inoculated with each isolate developed extensive necrotic lesions around the inoculation sites and the collar, respectively, and P. cactorum could be reisolated from all lesions. Controls showed no symptoms. P. cactorum is widespread in declining beech forests in central Europe (1). In Italy, P. cactorum occurs in soils of chestnut and oak forests and was isolated from collar and root lesions of declining walnut trees (3). To our knowledge, this is the first report of P. cactorum being associated with declining beech trees in Italy.

}, issn = {0191-2917}, doi = {10.1094/PDIS-92-12-1708A}, author = {A.M. Vettraino and T. Jung and A. Vannini} } @article {PPA:PPA864, title = {Evaluation of root damage to English walnut caused by five Phytophthora species}, journal = {Plant Pathology}, volume = {52}, number = {4}, year = {2003}, pages = {491{\textendash}495}, publisher = {Blackwell Science Ltd}, abstract = {

The pathogenicity of five species of Phytophthora to English walnut was studied in a greenhouse experiment. Phytophthora cinnamomi was the most aggressive species, causing severe root rot and seedling mortality. The other species tested, P. cambivora, P. citricola, P. cactorum and P. cryptogea, did not induce visible crown symptoms on seedlings 2 months after inoculation. Some strains of P. cambivora and P. cactorum also caused taproot damage to seedlings. All except one of the tested isolates caused significant necrosis of fine roots and a significant reduction of root weight compared with noninoculated seedlings. Reduction of above-ground plant development was not statistically significant. While P. cinnamomi is well known as an aggressive primary pathogen of English walnut, the other species of Phytophthora may act as predisposing factors to walnut decline, affecting root system development and increasing host vulnerability to environmental stress.

}, keywords = {English walnut, Juglans regia, pathogenicity, soilborne pathogens, walnut decline}, issn = {1365-3059}, doi = {10.1046/j.1365-3059.2003.00864.x}, url = {http://dx.doi.org/10.1046/j.1365-3059.2003.00864.x}, author = {A.M. Vettraino and Belisario, A. and Maccaroni, M. and A. Vannini} } @article {1324, title = {Phytophthora ramorum infection of coast live oak leaves in Californian forests and its capacity to sporulate in vitro}, journal = {Australasian Plant Pathology}, volume = {37}, year = {2008}, pages = {72-73}, publisher = {Springer Netherlands}, abstract = {

Coast live oak (Quercus agrifolia) is a known host for Phytophthora ramorum, the casual agent of sudden oak death in California, with symptoms expressed as necrotic stem cankers. In the forest, leaves on two saplings in California were found to be infected with P. ramorum and these were associated with infected bay laurel (Umbellularia californica) trees. Coast live oak leaves supported sporulation and produced chlamydospores in vitro. This is the first report to identify foliage of coast live oak as a source of infection of P. ramorum in the forest and its confirmation in in vitro inoculations.

}, issn = {0815-3191}, doi = {10.1071/AP07085}, url = {http://dx.doi.org/10.1071/AP07085}, author = {A.M. Vettraino and H{\"u}berli, D. and Garbelotto, M.} } @article {PPA:PPA839, title = {Scotch broom: a new host of Phytophthora megasperma in Italy}, journal = {Plant Pathology}, volume = {52}, number = {3}, year = {2003}, pages = {417{\textendash}417}, publisher = {Blackwell Science Ltd}, issn = {1365-3059}, doi = {10.1046/j.1365-3059.2003.00839.x}, url = {http://dx.doi.org/10.1046/j.1365-3059.2003.00839.x}, author = {A.M. Vettraino and A. Vannini} }