00667nas a2200181 4500008004100000245005700041210005700098260011100155300001200266490003200278100001800310700002400328700001500352700001700367700001900384700001800403856006400421 2010 eng d00aForest treatment strategies for Phytophthora ramorum0 aForest treatment strategies for Phytophthora ramorum aSanta Rosa, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station a239-2480 vGen. Tech. Rep. PSW-GTR-2291 aValachovic, Y1 aC. Lee, Marshall, J1 aScanlon, H1 aFrankel, S J1 aKliejunas, J T1 aPalmieri, K M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr229/00716nas a2200193 4500008004100000245007900041210006900120260011100189300001200300490003200312100001800344700001100362700001600373700001500389700001700404700001900421700001800440856006400458 2008 eng d00aWildland management of Phytophthora ramorum in northern California forests0 aWildland management of Phytophthora ramorum in northern Californ aSanta Rosa, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station a305-3120 vGen. Tech. Rep. PSW-GTR-2141 aValachovic, Y1 aLee, C1 aMarshall, J1 aScanlon, H1 aFrankel, S J1 aKliejunas, J T1 aPalmieri, K M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr214/02470nas a2200229 4500008004100000022001300041245007600054210006900130260001600199300001600215490000800231520175000239100002101989700002402010700002102034700002602055700002302081700002802104700001902132700002302151856006602174 2012 eng d a1878614600aDiscovery of a fourth evolutionary lineage of Phytophthora ramorum: EU20 aDiscovery of a fourth evolutionary lineage of Phytophthora ramor cJan-11-2012 a1178 - 11910 v1163 a

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.

1 aVan Poucke, Kris1 aFranceschini, Selma1 aWebber, Joan, F.1 aVercauteren, Annelies1 aTurner, Judith, A.1 aMcCracken, Alistair, R.1 aHeungens, Kurt1 aBrasier, Clive, M. uhttp://linkinghub.elsevier.com/retrieve/pii/S187861461200157200891nas a2200133 4500008004100000245006200041210006100103300001400164490000700178520044400185100001500629700001900644856009400663 2001 eng d00aInk disease in chestnuts: impact on the European chestnut0 aInk disease in chestnuts impact on the European chestnut a345–3500 v763 aA 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.1 aVannini, A1 aVettraino, A M uhttps://forestphytophthoras.org/references/ink-disease-chestnuts-impact-european-chestnut02799nas a2200181 4500008004100000022001400041245011500055210006900170260002900239300001200268520220300280100001502483700001502498700001302513700001702526700001902543856005502562 2012 eng d a1439-032900aBehaviour and survival of Phytophthora cambivora inoculum in soil-like substrate under different water regimes0 aBehaviour and survival of Phytophthora cambivora inoculum in soi bBlackwell Publishing Ltd ano–no3 a

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.

1 aVannini, A1 aBreccia, M1 aBruni, N1 aTomassini, A1 aVettraino, A M uhttp://dx.doi.org/10.1111/j.1439-0329.2012.00768.x02254nas a2200253 4500008004100000022001400041245011100055210006900166260002900235300001400264490000700278520146500285653002101750653001401771653002701785653002301812653001901835653002301854100001601877700001501893700001801908700001901926856005501945 2012 eng d a1365-305900aAlteration of physiological parameters of Austrocedrus chilensis by the pathogen Phytophthora austrocedrae0 aAlteration of physiological parameters of Austrocedrus chilensis bBlackwell Publishing Ltd a877–8880 v613 a

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.

10acypress root rot10aeffectors10ahydraulic conductivity10amal del cipr√©s10aphotosynthesis10axylem colonization1 aVélez, M L1 aSilva, P V1 aTroncoso, O A1 aGreslebin, A G uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02585.x02510nas a2200241 4500008004100000022001400041245009100055210006900146260002900215300001400244490000700258520180600265653001202071653001402083653002002097653002102117100001902138700001402157700001202171700001402183700001602197856005502213 2012 eng d a1365-305900aSurvival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates0 aSurvival of Phytophthora ramorum in Rhododendron root balls and  bBlackwell Publishing Ltd a166–1760 v623 a

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.

10abaiting10adetection10alatent survival10aSudden oak death1 aVercauteren, A1 aRiedel, M1 aMaes, M1 aWerres, S1 aHeungens, K uhttp://dx.doi.org/10.1111/j.1365-3059.2012.02627.x01785nas a2200241 4500008004100000022001400041245008400055210006900139260002600208300001400234490000700248520106700255653001901322653001801341653001801359653002401377653001901401100001901420700001701439700001701456700001501473856005501488 2003 eng d a1365-305900aEvaluation of root damage to English walnut caused by five Phytophthora species0 aEvaluation of root damage to English walnut caused by five Phyto bBlackwell Science Ltd a491–4950 v523 a

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.

10aEnglish walnut10aJuglans regia10apathogenicity10asoilborne pathogens10awalnut decline1 aVettraino, A M1 aBelisario, A1 aMaccaroni, M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00864.x01408nas a2200241 4500008004100000022001400041245010900055210006900164260002700233300001200260490000700272520068900279100001900968700001800987700001601005700001501021700001601036700001601052700001301068700001501081700001501096856005501111 2002 eng d a1439-032900aOccurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees0 aOccurrence of Phytophthora species in oak stands in Italy and th bBlackwell Science Ltd. a19–280 v323 a

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.

1 aVettraino, A M1 aBarzanti, G P1 aBianco, M C1 aRagazzi, A1 aCapretti, P1 aPaoletti, E1 aLuisi, N1 aAnselmi, N1 aVannini, A uhttp://dx.doi.org/10.1046/j.1439-0329.2002.00264.x01913nas a2200205 4500008004100000022001400041245014300055210006900198260002500267300001200292490000800304520125600312100001701568700001301585700001601598700001301614700001701627700001501644856004801659 2005 eng d a0929-187300aOccurrence and distribution of Phytophthora; species in European chestnut stands, and their association with Ink Disease and crown decline0 aOccurrence and distribution of Phytophthora species in European  bSpringer Netherlands a169-1800 v1113 a

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 °C, maximum temperature above 28 °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.

1 aVettraino, A1 aMorel, O1 aPerlerou, C1 aRobin, C1 aDiamandis, S1 aVannini, A uhttp://dx.doi.org/10.1007/s10658-004-1882-000466nas a2200145 4500008004100000022001400041245006500055210006400120260002600184300001400210490000700224100001900231700001500250856005500265 2003 eng d a1365-305900aScotch broom: a new host of Phytophthora megasperma in Italy0 aScotch broom a new host of Phytophthora megasperma in Italy bBlackwell Science Ltd a417–4170 v521 aVettraino, A M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00839.x01366nas a2200169 4500008004100000022001400041245012200055210006900177260002500246300001000271490000700281520081700288100001901105700001601124700001801140856003801158 2008 eng d a0815-319100aPhytophthora ramorum infection of coast live oak leaves in Californian forests and its capacity to sporulate in vitro0 aPhytophthora ramorum infection of coast live oak leaves in Calif bSpringer Netherlands a72-730 v373 a

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.

1 aVettraino, A M1 aHüberli, D1 aGarbelotto, M uhttp://dx.doi.org/10.1071/AP0708502679nas a2200169 4500008004100000022001400041245008100055210006900136260001200205300001600217490000700233520211000240100001902350700001202369700001502381856011302396 2008 eng d a0191-291700aFirst report of Phytophthora cactorum associated with beech decline in Italy0 aFirst report of Phytophthora cactorum associated with beech decl c12/2008 a1708 - 17080 v923 a

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°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 × 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°C, minimum 6 to 8°C and maximum 30 to 33°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°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.

1 aVettraino, A M1 aJung, T1 aVannini, A uhttps://forestphytophthoras.org/references/first-report-phytophthora-cactorum-associated-beech-decline-italy