01616nas a2200181 4500008004100000022004200041245011400083210006900197300001400266490000700280520101100287100001801298700001301316700001701329700001601346700001601362856005601378 2013 eng d a1175-9003 (print), 1179-352X (online)00aSurveillance methods to determine tree health, distribution of kauri dieback disease and associated pathogens0 aSurveillance methods to determine tree health distribution of ka a235–2410 v663 a

Kauri dieback is a pest issue that is increasingly affecting kauri forests. A water and soilborne pathogen, Phytophthora taxon Agathis (PTA), has been identified as a causal agent of kauri dieback at multiple locations, particularly within Auckland and Northland. In 2008, a passive surveillance and adaptive management programme was initiated to manage the disease across the natural range of kauri. Surveys were initially undertaken to determine the distribution and rate of spread of kauri dieback on private land in the Auckland region. Methods to evaluate and monitor overall tree health, disease symptoms and other potential contributing factors were developed. Diagnostic sampling was undertaken to isolate and identify pathogens associated with kauri dieback. Along with PTA, other Phytophthora species and environmental stress were frequently associated with symptoms at over 400 properties inspected. Further management is now required to develop control tools and mitigate further spread.

1 aWaipara, N.W.1 aHill, S.1 aHill, L.M.W.1 aHough, E.G.1 aHorner, I J uhttp://www.nzpps.org/nzpp_abstract.php?paper=66235000843nas a2200181 4500008004100000245011300041210006900154260012100223300000900344490003200353100001900385700002100404700001900425700002200444700002300466700002700489856014500516 2009 eng d00aPhytophthora ramorum and Phytophthora kernoviae in England and Wales—Public Consultation and New Programme0 aPhytophthora ramorum and Phytophthora kernoviae in England and W aSanta Cruz, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.c04/2010 a6-140 vGen. Tech. Rep. PSW-GTR-2291 aWalters, Keith1 aSansford, Claire1 aSlawson, David1 aFrankel, Susan, J1 aKliejunas, John, T1 aPalmieri, Katharine, M uhttps://forestphytophthoras.org/references/phytophthora-ramorum-and-phytophthora-kernoviae-england-and-wales%E2%80%94public-consultation-and03083nas a2200169 4500008004100000022001400041245009000055210006900145260001600214300001400230490000700244520255200251100001302803700001302816700001402829856007002843 2014 eng d a0191-291700aFirst Report of Phytophthora tentaculata Causing Stem and Root Rot on Celery in China0 aFirst Report of Phytophthora tentaculata Causing Stem and Root R cJan-03-2014 a421 - 4210 v983 a

Celery (Apium graveolens) is an important vegetable in China. In August 2012, about 20 to 70% declining plants with root and basal stem rot were observed in Bengbu, Anhui Province, China. Typical symptoms included large dark brown to black water-soaked lesions near the soil line of stems. As the disease progressed, lesions girdled the stem, and plants became brown, wilted, and eventually died. A Phytophthora-like organism was consistently isolated from symptomatic tissues on a selective medium, P5ARP. Resultant isolates were identified as Phytophthora tentaculata based on their morphological features and rDNA sequence. Sporangia, chlamydospores, hyphal swellings, and oospores were produced on V8 agar. Sporangia were ovoid to pyriform, 28.5 to 52.5 × 21.5 to 40.6 μm, average 35.3 × 29.8 μm, with one or occasionally two papillae. Chlamydospores were spherical, 21.3 to 30.2 μm in diameter, average 25.7 μm. The isolates were homothallic, and one or occasionally two paragynous antheridia were attached to the global oogonia (24 to 39 μm in diameter, average 29.5 μm). The internal transcribed spacer region of rDNA was amplified with primer pair ITS1/ITS4 for one isolate (1), and the sequence (GenBank Accession No. KF501392) showed >99% similarity with those P. tentaculata isolates deposited in GenBank (AJ854302.1). Pathogenicity was confirmed by inoculating Shijihuangqin, a local cultivar of celery, with isolate PT12081. The isolate was cultivated on V8 agar at 25°C for 5 to 7 days to produce sporangia. Five 2-month-old, disease-free celery were drench-inoculated with 10 ml of a suspension of 2 × 104 zoospores/ml, and five control plants per pot were treated with sterile water. There were four pots for each of the inoculated and non-inoculated treatments, and the experiment was repeated twice. All plants were maintained at 25°C for 10 days. Symptoms similar to those observed in the field developed 7 days after inoculation. Ten days later, five plants wilted and two or three died in each pot inoculated with PT12081, but the control plants remained symptomless. P. tentaculata was consistently re-isolated from the symptomatic plants. P. tentaculata has been reported to infect Chrysanthemum spp., Delphinium ajacis, Verbena spp., and Origanum vulgare (2,3). To our knowledge, this is the first report of Phytophthora blight caused by P. tentaculata on celery in China.

1 aWang, T.1 aZhao, W.1 aQi, R.-D. uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-13-0592-PDN00365nas a2200133 4500008004100000022001300041245002900054210002900083260000900112300000900121490000700130100002500137856006900162 1970 eng d a0031949X00aTaxonomy in Phytophthora0 aTaxonomy in Phytophthora c1970 a11410 v601 aWaterhouse, Grace, M uhttps://forestphytophthoras.org/references/taxonomy-phytophthora00362nas a2200109 4500008004100000245004800041210004700089300000900136490000700145100002000152856008000172 1963 eng d00aKey to the species of Phytophthora de Bary.0 aKey to the species of Phytophthora de Bary a1-220 v921 aWaterhouse, G M uhttps://forestphytophthoras.org/references/key-species-phytophthora-de-bary00638nas a2200145 4500008004100000245006800041210006500109260010800174300001200282490004100294100001700335700001600352700002200368856010200390 2009 eng d00aManagement of P. kernoviae and P. ramorum in southwest England.0 aManagement of P kernoviae and P ramorum in southwest England aMonterey, CaliforniabU.S. Department of Agriculture, Forest Service Pacific Southwest Research Station a177-1830 vGeneral Technical Report PSW-GTR-2211 aWebber, Joan1 aGoheen, E M1 aFrankel, Susan, J uhttps://forestphytophthoras.org/references/management-p-kernoviae-and-p-ramorum-southwest-england04270nas a2200145 4500008004100000245012300041210006900164300000700233490000700240520377500247100001504022700001504037700001704052856005504069 2010 eng d00aDieback and mortality of plantation Japanese larch (Larix kaempferi) associated with infection by Phytophthora ramorum0 aDieback and mortality of plantation Japanese larch Larix kaempfe a190 v223 a

The invasive pathogen Phytophthora ramorum is the cause of ’sudden oak death’, a dieback and mortality of more than one million live-oak and tanoak trees along 1500 km of near-coastal native forest in California and Oregon since 1995 (Rizzo et al., 2002; Frankel, 2008). P. ramorum has also spread across Europe , mainly within the ornamental nursery trade. From 2003 onwards it was found infecting rhododendron and woodland trees outside nurseries in Britain (Brasier et al., 2004) and has recently spread to native Vaccinium swards (P. Beales, personal communication). Until now, tree infections in Britain have been comparatively few (<100), mostly foliage or stems of Fagaceae (Fagus, Nothofagus, Quercus and Castanea) in the vicinity of infected Rhododendron in south west England (Webber, 2008). In August 2009 extensive dieback and mortality was observed in mature (25-30 m tall) and juvenile plantation Japanese larch, Larix kaempferi,at multiple sites in south west England (Figs. 1, 2). Symptoms included black or purple discoloured needles (Fig. 3), aborted bud flush, wilting and senescence of dwarf shoots and needle loss. Affected trees often had copious resin bleeding on the trunk, branches and side shoots plus dieback of branches and sometimes of the entire crown. Phloem lesions were often present under resinous outer bark. These usually had deep pink to maroon-red margins, older lesion areas being rusty-brown to cinnamon brown.

When symptom-bearing needles were surface-sterilised in 70% ethanol for 30 seconds or small pieces of older phloem lesion were plated onto Phytophthora selective medium (Brasier et al., 2005), P. ramorum was obtained from 25-40% of the samples. Identity was confirmed by sequencing of ITS rDNA regions (GenBank Accession No. HQ010359). P. ramorum was not obtained from the pink-maroon lesion margins. Pathogenicity of a P. ramorum isolate from L. kaempferi was tested by dipping 15 cm long L. kaempferi shoots into a zoospore suspension and damp chamber incubating for 12h light/12h dark cycle at 18°C. On half the shoots all needles were wounded by tip cutting. After seven days each needle was categorised as blackened, browned/brown bands, chlorotic or green, surface sterilised and plated onto selective medium. Both unwounded and wounded blackened needles yielded P. ramorum at high frequency (Table 1). When needles were mounted in lactic acid cotton blue and viewed 24 h later, sporangia and occasionally chlamydospores were observed on the surfaces with an exceptional 2685 sporangia counted on one unwounded needle (Fig. 4).

P. ramorum has so far been isolated from L. kaempferi at 68 currently known plantations where symptoms are present in southwest England . In May 2010 larch plantations with similar symptoms were discovered in south Wales and P. ramorum has again been isolated at multiple sites. Overall an estimated 2400 ha or c. 0.6 million mature larch have been affected to date. A large area of juvenile larch is also affected. This is the first widespread and lethal damage caused by P. ramorum to a conifer and the first to a commercial plantation tree. Adjacent to some affected larch sites in southwest England , secondary infection of Fagus sylvatica, Nothofagus obliqua, Castanea sativa, Betula pendula, Rhododendron ponticum, Tsuga heterophylla and Pseudotsuga menziesii is also occurring, apparently as result of the high levels of P. ramorum inoculum produced from larch foliage.  

1 aWebber, JF1 aMullett, M1 aBrasier, C M uhttp://dx.doi.org/10.5197/j.2044-0588.2010.022.01902312nas a2200193 4500008004100000022001400041245007700055210006900132260002900201300001200230520172200242100001501964700001901979700001501998700001802013700001702031700001502048856005502063 2011 eng d a1439-032900aIsolation of Phytophthora lateralis from Chamaecyparis foliage in Taiwan0 aIsolation of Phytophthora lateralis from Chamaecyparis foliage i bBlackwell Publishing Ltd ano–no3 a

Summary Following the discovery in 2008 of Phytophthora lateralis in forest soil under old-growth yellow cedar (Chamaecyparis obtusa var. formosana) in north-east Taiwan, further sampling was undertaken in the same region. Soil, root and symptomatic foliage samples were collected from five separate sites where C. obtusa was the dominant species in cloud forests at ca. 1800–2500 m. Soil and fine root samples were baited with cedar needles; both direct isolation and cedar needle baiting were used on foliage samples. Phytophthora lateralis was obtained from soil at three of the sites, but only from three of the 27 soil samples overall. Only one of 25 root samples yielded the pathogen, and this was associated with infested soil. Three foliage samples with symptoms visible as dark brown to black frond tips also yielded P. lateralis; these came from two different sites. This is the first record of P. lateralis infecting the foliage of C. obtusa. Moreover, when some of the symptomatic Chamaecyparis foliage segments were incubated, sporangia of P. lateralis formed on the necrotic tissues, sometimes in the axils of needle segments. The study provides evidence that P. lateralis has both a soil/root infecting phase and an aerial or foliar infecting phase in Taiwan, which is consistent with its unusual combination of water-dispersed (non-papillate) and aerially dispersed (caducous) sporangia. It also demonstrates the importance of investigating the biology, aetiology and ecological behaviour of Phytophthoras in their native, endemic environments.

1 aWebber, JF1 aVettraino, A M1 aChang, T T1 aBellgard, S E1 aBrasier, C M1 aVannini, A uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00729.x03719nas a2200217 4500008004100000022001400041245011600055210006900171260001200240300000700252490000800259520303800267100001703305700002003322700001403342700001903356700002203375700002103397700001903418856006403437 2015 eng d a1179-315500aA taxonomic revision of Phytophthora Clade 5 including two new species, Phytophthora agathidicida and P. cocois0 ataxonomic revision of Phytophthora Clade 5 including two new spe c10/2015 a210 v2053 a

Phytophthora Clade 5 is a very poorly studied group of species of oomycete chromists, consisting of only two known species P. castaneae (≡ P. katsurae, nom. illegit.) and P. heveae with most isolates from East Asia and the Pacific Islands. However, isolates of two important disease-causing chromists in Clade 5, one of kauri (Agathis australis) in New Zealand, the other of coconut (Cocos nucifera) in Hawaii, poorly match the current species descriptions. To verify whether these isolates belong to separate species a detailed morphological study and phylogenetic analysis consisting of eight genetic loci was conducted. On the basis of genetic and morphological differences and host specificity, we present the formal description of two new species in Clade 5, Phytophthora agathidicida sp. nov. and Phytophthora cocois sp. nov. To clarify the typification of the other Clade 5 species, an authentic ex-holotype culture of Phytophthora castaneae is designated and P. heveae is lectotypified and epitypified.

1 aWeir, B., S.1 aPaderes, E., P.1 aAnand, N.1 aUchida, J., Y.1 aPennycook, S., R.1 aBellgard, S., E.1 aBeever, R., E. uhttp://biotaxa.org/Phytotaxa/article/view/phytotaxa.205.1.202015nas a2200145 4500008004100000245012800041210006900169300001200238490000700250520150300257100001901760700001301779700001201792856006501804 2006 eng d00aThe possible origin and relation of Phytophthora katsurae and P. heveae, discovered in a protected natural forest in Taiwan0 apossible origin and relation of Phytophthora katsurae and P heve a273-2770 v473 aWhen a total of 531 soil samples collected from 1976 to 2000 from various locations distributed in every county on the island of Taiwan was assayed, sixteen isolates of Phytophthora katsurae and nine isolates of P. heveae were recovered from three and four counties, respectively. Phytophthora katsurae and P. heveae were isolated from a protected natural forest located atop a hill at Lenhuachih without higher land within the range of vision, suggesting that both species are indigenous to Taiwan. Phytophthora katsurae is distinguished from the similar P. heveae by its verrucose oogonial wall. The number of protrusions produced by the Taiwanese isolates of P. katsurae varied greatly ranging from 2 to 23 per oogonium, indicating the unsteadiness of this taxonomical characteristic. Oogonia produced by isolates of P. katsurae obtained from Hawaii contained very few protrusions. Moreover, most oogonia produced by two of these isolates did not have any protrusions and were indistinguishable from those produced by P. heveae. Results suggest the development of P. heveae directly from P. katsurae by loss of oogonial protrusions. The high level of ITS sequence similarity between P. heveae and P. katsurae in comparison with their relationships to other Phytophthora species tested also support the possibility of the recent development of one species from the other species.1 aWen-Hsiung, KO1 aWang, SY1 aAnn, PJ uhttp://ejournal.sinica.edu.tw/bbas/content/2006/3/Bot473-07/02388nas a2200229 4500008004100000022001400041245007900055210006900134300001600203490000800219520165000227100001901877700002001896700002401916700001801940700002401958700001701982700001901999700001802018700002202036856010002058 2001 eng d a0953-756200aPhytophthora ramorum sp. nov., a new pathogen on Rhododendron and Viburnum0 aPhytophthora ramorum sp nov a new pathogen on Rhododendron and V a1155 - 11650 v1053 a

Since 1993, a hitherto unidentified Phytophthora species has been found associated with twig blight disease in Rhododendron and, sporadically, Viburnum. The morphology and growth characteristics of fourteen isolates from Germany and the Netherlands were investigated, together with their breeding system, the internal transcribed spacer (ITS) regions of the ribosomal DNA, amplified fragment length polymorphism (AFLP) fingerprints, and isozyme profiles, which were compared to those of a number of outgroup species. Morphologically the isolates are characterized by abundant production of chlamydospores and elongate, ellipsoid, deciduous sporangia with a short pedicel, in which they resemble P. palmivora. However, sporangia were semi-papillate, chlamydospores were much larger and cardinal temperatures much lower than those of P. palmivora. Oogonia with amphigynous antheridia and plerotic oospores were produced in dual cultures with an A2 mating type strain of P. cryptogea. ITS1 and ITS2 sequences of the unidentified species were closest to those of P. lateralis, but differed in three and eight nucleotides respectively from the latter species. AFLP fingerprints and isozyme patterns of malate dehydrogenase (MDH-2) and malic enzyme (MDHP) showed that the isolates formed a homogeneous group, distinct from all examined outgroup species, including P. lateralis. It was concluded that they represent a new Phytophthora species, described here as P. ramorum sp. nov. In pathogenicity tests all isolates of P. ramorum were pathogenic to Rhododendron.

1 aWerres, Sabine1 aMarwitz, Rainer1 aMan_In’t_veld, WA1 aDe Cock, AWAM1 aBonants, Peter, J M1 aDe Weerdt, M1 aThemann, Karin1 aIlieva, Elena1 aBaayen, Robert, P uhttp://www.sciencedirect.com/science/article/B7XMR-4RS3YCS-4/2/9f9142119aa3952d3dbc8811be4860bb00467nas a2200109 4500008004100000245009100041210006900132300001200201490000700213100001300220856012400233 1994 eng d00aImpact of Phytophthora species on native vegetation of Australia and Papua New Guinea.0 aImpact of Phytophthora species on native vegetation of Australia a190-2090 v231 aWeste, G uhttps://forestphytophthoras.org/references/impact-phytophthora-species-native-vegetation-australia-and-papua-new-guinea00535nas a2200145 4500008004100000022001400041245006400055210006000119260008700179300001200266490000700278100001300285700001400298856007700312 1987 eng d a0066-428600aThe biology of Phytophthora cinnamomi in Australian forests0 abiology of Phytophthora cinnamomi in Australian forests a{4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139}b{ANNUAL REVIEWS INC} a207-2290 v251 aWeste, G1 aMarks, CG uhttp://www.annualreviews.org/doi/abs/10.1146/annurev.py.25.090187.00123100542nam a2200157 4500008004100000020001800041245010200059210006900161260001300230300001400243100001600257700001400273700001200287700001500299856007000314 1990 eng d a978012372180800aPCR Protocols amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics0 aPCR Protocols amplification and direct sequencing of fungal ribo bElsevier a315 - 3221 aWhite, T.J.1 aBruns, T.1 aLee, S.1 aTaylor, J. uhttps://linkinghub.elsevier.com/retrieve/pii/B978012372180850042101781nas a2200157 4500008004100000022001400041245010300055210006900158260001600227300001600243490000700259520124500266100002401511700002301535856006501558 2015 eng d a0191-291700aBioassay Conditions for Infection of Pinus radiata Seedlings with Phytophthora pinifolia Zoospores0 aBioassay Conditions for Infection of Pinus radiata Seedlings wit cJan-09-2015 a1204 - 12090 v993 a

Phytophthora pinifolia is known to cause a devastating disease on Monterey pine in Chile. Although this pathogen is not yet present in the United States, there is reason for concern. The main source of Monterey pine genetic material is found in California and there is potential for other important tree species to be hosts. The study presented here was conducted to develop a method to produce zoospores and determine optimal conditions for infection to be used in future host range studies. Abundant zoospores were produced when agar plugs containing P. pinifolia mycelia were ground into suspension prior to transfer in a solution of carrot broth. These zoospores then were used to inoculate Monterey pine seedlings under various conditions. Infected plants displayed necrotic crowns and stems, often resulting in wilting of the seedling. Consistent infection occurred when seedlings were wounded by trimming needles prior to inoculation and exposure of inoculated seedlings to constant dew for 5 days. Dew chamber temperature (15, 20, or 25°C) did not affect the infection rate. Information obtained from this study will be useful in screening other hosts for susceptibility to P. pinifolia infection.

1 aWidmer, Timothy, L.1 aDodge, Stephen, C. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-12-14-1306-RE03226nas a2200133 4500008004100000245007300041210006900114260001200183300001000195490000800205520277900213100001502992856008503007 2011 eng d00aSurvival of Phytophthora kernoviae oospores, sporangia, and mycelium0 aSurvival of Phytophthora kernoviae oospores sporangia and myceli c07/2011 a15-230 v41S3 a

Interpretive Summary: A recently discovered plant pathogen has been found to attack many different hosts including rhododendrons and beech trees in the United Kingdom and New Zealand. Although not currently known to exist in the United States, it is a pathogen of concern due to its destructive nature and threat to valuable hosts in the U.S. This pathogen produces different propagules for spread and survival of which very little is known. This study was done to learn how long these propagules can survive at different temperatures. Results show that one propagule type can survive buried in sand for up to a year at moderate temperatures but declines rapidly when exposed for increased periods of time as temperatures increase. In addition, this pathogen is able to persist and produce survival propagules in sand with very minimal nutrients. These results provide information to regulatory agency personnel and scientists to develop guidelines that help in limiting the spread of this pathogen. Technical Abstract: Phytophthora kernoviae is a pathogen recently found only in the U.K. and New Zealand. Phytophthora kernoviae, not known to produce chlamydospores, is homothallic and produces abundant oospores and sporangia. This study was conducted to examine long-term survival of oospores, sporangia, and mycelium buried in sand at different temperatures. Viability of oospores embedded onto 20-µm-mesh screens and buried in sand at 4, 10, 20, and 30C was measured over time by staining with tetrazolium bromide solution. For one isolate, viability was 82, 81, 79, and 58% and 86, 75, 82, and 78% for the other isolate at 4, 10, 20, and 30C, respectively, after 1 year. The infection potential of the oospores was checked by removing additional embedded screens and placing on rhododendron leaf disks. No necrosis was observed on leaf disks exposed to oospores buried for 1 year at 30C. However, necrosis was observed on leaf disks at the other temperatures after the same time. Oospores exposed 6 h at 50C and 24 h at 40 and 50C were less viable than controls and did not germinate. To study survival of sporangia and mycelium, sand was infested only with sporangia or mycelium from four isolates, incubated at different temperatures, and plated on Phytophthora-selective medium over time. All isolates reacted in the same manner with populations generally declining within 1 week but then remaining steady over time. Soil extractions of the infested sand showed that over time sporangia and oospores formed at all temperatures except at 30C. This demonstrates that P. kernoviae oospores can persist in sand for long periods of time at different temperatures, which could be a significant factor in spread of this pathogen.

1 aWidmer, TL uhttp://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=25963501821nas a2200145 4500008004100000022001400041245007200055210006900127300001400196490000800210520131400218653002001532100002301552856010001575 2010 eng d a1878-614600aPhytophthora kernoviae oospore maturity, germination, and infection0 aPhytophthora kernoviae oospore maturity germination and infectio a661 - 6680 v1143 a

Limited information is known on the basic biology of the recently described Phytophthora kernoviae that produces homothallic oospores. In this study, different P. kernoviae isolates were used to investigate oospore maturity, germination, and infection. All isolates produced oospores in V8 broth at 20†$ınfty$C in the dark by 6†d. Oospores also formed at 10 and 15†$ınfty$C, but did not form at 25 and 28†$ınfty$C. Continuous light inhibited oospore production of some isolates but had no negative effect on others. Maturation time of the oospores, as noted by germination and staining with tetrazolium bromide, was not much different among the isolates between 2 and 14 weeks. Oospore germination was optimal at 18 and 20†$ınfty$C, and did not occur at 5, 25, and 30†$ınfty$C. Oospore germination under continuous light was higher than in the dark, but individual isolates showed variable results. Rhododendron leaf disks inoculated with oospores and maintained in the dark at 20†$ınfty$C were necrotic after 1 week, while those kept under continuous light did not develop necrosis. The percentage of leaf disks infected with P. kernoviae was lower in the leaves exposed to continuous light (40†%) compared to those kept in the dark (100†%).

10aViability stain1 aWidmer, Timothy, L uhttp://www.sciencedirect.com/science/article/B9879-508K88P-1/2/e35155432b3146cdabc05226a599fa7501898nas a2200157 4500008004100000245011000041210006900151260001200220300001400232490000700246520139000253100001601643700001701659700001501676856004901691 2012 eng d00aInfectivity and inoculum production of Phytophthora ramorum on roots of eastern United States oak species0 aInfectivity and inoculum production of Phytophthora ramorum on r c11/2012 a1675-16820 v963 a

Little is known about colonization of roots of trees by Phytophthora ramorum. We examined zoospore concentration and exposure time needed to infect six Quercus (oak) species and the inoculum produced from their roots. Sprouted acorns, exposed to zoospores (3,000/ml) for different times and transplanted to potting soil, were susceptible to infection within 1 h of exposure but root weights were not impacted after 4 weeks (P = 0.952). Roots of Quercus prinus seedlings, inoculated with sporangia, had 0.6 to 3.2% colonization of the total root mass after 5 months. Neither root lesions nor obvious root sloughing were observed. Inoculum threshold levels were tested by exposing radicles to varying zoospore concentrations for 24 h. Results showed that radicle infection occurred even at 1 zoospore/ml. To test inoculum production, roots were inoculated with sporangia and transplanted into pots. Periodically, samples of runoff were collected and plated on selective medium. Afterward, root segments were plated to calculate percent colonization. After 16 and 35 days, root colonization and inoculum production from oak was lower than that of Viburnum tinus, a positive control. This study shows that P. ramorum is able to infect sprouted oak acorns and produce secondary inoculum, which may be important epidemiologically.

1 aWidmer, T L1 aShishkoff, N1 aDodge, S C uhttp://dx.doi.org/10.1094/PDIS-12-11-1024-RE00457nas a2200085 4500008004100000245011800041210006900159100001800228856012500246 2005 eng d00aField validation of laboratory tests used in screening Port-Orford-cedar for resistance to Phytophthora lateralis0 aField validation of laboratory tests used in screening PortOrfor1 aWing, Adam, B uhttps://forestphytophthoras.org/references/field-validation-laboratory-tests-used-screening-port-orford-cedar-resistance01625nas a2200181 4500008004100000022001300041245012800054210006900182300001400251490000700265520092800272653002601200653001901226653003001245100001601275700001601291856013601307 2001 eng d a1437478100aMolecular diagnosis of Phytophthora lateralis in trees, water, and foliage baits using multiplex polymerase chain reaction.0 aMolecular diagnosis of Phytophthora lateralis in trees water and a275 - 2830 v313 a

A polymerase chain reaction (PCR)-based protocol for detection of Phytophthora lateralis in plant tissues and water is described. Base-pair (bp) deletions in both of the ribosomal DNA internal transcribed spacer (ITS) regions in P. lateralis were used to design complementary PCR primer sequences that amplify a 738 bp fragment only if P. lateralis DNA is present in the sample. Universal control primers based on conserved sequences of the nuclear ribosomal small subunit are included in a multiplexed reaction, providing an internal check on the procedure. The universal primers amplify an approximately 550 bp fragment that is common to plants, protists, and true fungi. The procedure reliably detects P. lateralis in cedar stem tissues and in roots. Positive reactions were obtained with as few as 200 P. lateralis zoospores in water. (English) [ABSTRACT FROM AUTHOR]

10aPHYTOPHTHORA diseases10aPLANT diseases10apolymerase chain reaction1 aWinton, L M1 aHansen, E M uhttps://forestphytophthoras.org/references/molecular-diagnosis-phytophthora-lateralis-trees-water-and-foliage-baits-using-multiplex02204nas a2200181 4500008004100000245012700041210006900168300001100237490000800248520162800256100001601884700001501900700001401915700001501929700001501944700001201959856005101971 2011 eng d00aCOST action FP0801 - established and emerging phytophthora: Increasing threats to woodland and forest ecosystems in Europe0 aCOST action FP0801 established and emerging phytophthora Increas a7–130 v41S3 a

With the rapidly growing international trade in plants and ongoing impacts of climate change, impacts of plant pathogens in the genus Phytophthora are increasing, threatening the biodiversity and sustainability of European forest ecosystems. Through the European Cooperation in Science and Technology (COST) framework Action FP0801, scientists and disease-control experts are working on Phytophthora in forest ecosystems with the overall aim of increasing understanding of the biology and ecology of Phytophthora species with potential to cause damage to European forestry. This knowledge will be used in the development of effective control and management protocols for the problems caused. Outcomes of the Action will be promoted in an effort to increase knowledge and awareness of the problem by disseminating information to end-users and authorities in the forestry sector, and to the general public. Four interrelated working groups have been established to (i) examine the ways in which Phytophthora species spread into and within Europe; (ii) determine how phytophthoras kill woody plants and elucidate mechanisms for host resistance; (iii) disseminate state-of-the-art rapid molecular diagnostic techniques, and (iv) seek sustainable protocols for management and control of the diseases. The project is expected to increase understanding of threats to forest ecosystems by Phytophthora, improve the ability to rapidly detect phytophthora in environmental samples, and provide sustainable management solutions to the diseases caused by these destructive organisms.

1 aWoodward, S1 aVannini, A1 aWerres, S1 aOßwald, W1 aBonants, P1 aJung, T uhttp://researchrepository.murdoch.edu.au/4375/