00593nas a2200145 4500008004100000245006200041210005700103260008600160300001100246100002200257700002200279700002000301700001900321856010700340 2007 eng d00aPhytophthora kernoviae – of southern hemisphere origin?0 aPhytophthora kernoviae of southern hemisphere origin aMonterey, Calif. Coll. of Nat. Resourc., Univ. of Calif., Berkeley.cAugust, 2007 a1 page1 aRamsfield, Tod, D1 aDick, Margaret, A1 aBeever, Ross, E1 aHorner, Ian, J uhttps://forestphytophthoras.org/references/phytophthora-kernoviae-%E2%80%93-southern-hemisphere-origin01636nas a2200217 4500008004100000245004200041210004200083260010800125300001000233490004100243520090600284100001901190700001401209700001601223700001601239700001801255700001401273700002701287700002201314856008201336 2009 eng d00aPhytophthora kernoviae in New Zealand0 aPhytophthora kernoviae in New Zealand aMonterey, CaliforniabU.S. Department of Agriculture, Forest Service Pacific Southwest Research Station a47-530 vGeneral Technical Report PSW-GTR-2213 a

Phytophthora kernoviae was first recognised in New Zealand in 2005 by DNA sequencing of an isolate that had been recovered from diseased Annona cherimola (cherimoya or custard apple) in an abandoned orchard in Northland in 2002. Subsequent investigation has recovered P. kernoviae from the soil in Northland, Auckland, Bay of Plenty and Taupo regions. Similarity between P. kernoviae and descriptions of an undescribed Phytophthora sp. found previously in New Zealand indicates that the organism has been present here since at least 1953. This, along with the geographic range of P. kernoviae, and a polymorphism in the ITS sequence, suggest that the pathogen has been present in New Zealand for an even longer time. Little is known of the ecological behaviour of the pathogen in New Zealand; disease has only been recorded on A. cherimola.

1 aRamsfield, T D1 aDick, M A1 aBeever, R E1 aHorner, I J1 aMcAlonan, M J1 aHill, C F1 aGoheen, Ellen Michaels1 aFrankel, Susan, J uhttps://forestphytophthoras.org/references/phytophthora-kernoviae-new-zealand02555nas a2200217 4500008004100000022001400041245011100055210006900166300001200235490000700247520187500254653001602129653002302145653001802168100002202186700001702208700002302225700002602248700002502274856003802299 2010 eng d a0815-319100aPhytophthora elongata sp. nov., a novel pathogen from the Eucalyptus marginata forest of Western Australia0 aPhytophthora elongata sp nov a novel pathogen from the Eucalyptu a477-4910 v393 a

A novel homothallic species of Phytophthora producing semipapillate sporangia on sympodially branching sporangiophores, thick-walled oospores in smooth-walled oogonia, and paragynous antheridia is described here as Phytophthora elongata sp. nov. DNA sequencing of the internal transcribed spacer (ITS) DNA and coxI gene confirm P. elongata as a distinct species within ITS clade 2. It has been isolated in the northern jarrah forest of Western Australia (WA) from the roots and collars of dead and dying Eucalyptus marginata and occasionally Corymbia calophylla in rehabilitated bauxite mine pits. It has also been associated with dead and dying plants of several mid- and understorey species in the northern and southern jarrah forest—Banksia grandis, Leucopogon propinquus, Dryandra squarrosa and an Andersonia sp., as well as the monocotyledonous Xanthorrhoea preissii, X. gracilis and Patersonia xanthina. P. elongata has also been isolated from sandy soils and loams in Victoria in eastern Australia. The pathogenicity of P. elongata to E. marginata and Banksia spp. has been shown in this and earlier studies. Due to the uniformity of the ITS DNA and cox 1 sequence data in WA, P. elongata may be the result of a recent clonal introduction. More pathogenicity tests on a wider range of native plant species are needed to assess the host range of P. elongata and its invasive potential in WA.

10abiosecurity10anatural ecosystems10aphylogenetics1 aRea, Alexander, J1 aJung, Thomas1 aBurgess, Treena, I1 aStukely, Michael, J C1 aHardy, Giles St, E J uhttp://dx.doi.org/10.1071/AP1001402154nas a2200265 4500008004100000022001400041245015600055210006900211260002900280300001600309490000700325520128800332653002601620653002301646653001401669653001401683653002601697653002801723100001301751700001701764700002101781700001901802700001201821856005501833 2011 eng d a1365-305900aTwo novel and potentially endemic species of Phytophthora associated with episodic dieback of Kwongan vegetation in the south-west of Western Australia0 aTwo novel and potentially endemic species of Phytophthora associ bBlackwell Publishing Ltd a1055–10680 v603 a

Two novel homothallic species of Phytophthora causing dieback of Kwongan vegetation in south-west Western Australia are described here as Phytophthora arenaria sp. nov. and Phytophthora constricta sp. nov. DNA sequencing of the ITS rDNA and cox1 gene confirmed that P. arenaria and P. constricta are unique species residing in ITS clades 4 and 9, respectively. Phytophthora arenaria has been isolated from vegetation occurring on the northern sandplains which are warmer and drier than the southern sandplains from which P. constricta has been predominantly isolated, and both species appear morphologically and physiologically well adapted to the ecosystems in which they occur. Both species have been associated mainly with dead and dying Banksia species and the pathogenicity of both P. arenaria and P. constricta to Banksia attenuata was confirmed in this study. The combination of unique DNA sequences, including considerable variation in cox1 sequence data, thick oospore walls and physiological characteristics that appear to be adaptations favouring survival in the harsh Kwongan ecosystem suggest that these species may be endemic to Western Australia.

10aMediterranean climate10anatural ecosystems10apathogens10aphylogeny10aPhytophthora arenaria10aPhytophthora constricta1 aRea, A J1 aBurgess, T I1 aHardy, St, G E J1 aStukely, M J C1 aJung, T uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02463.x04285nas a2200157 4500008004100000022001400041245011100055210006900166260001600235300002000251520373900271100001704010700002004027700001404047856006604061 2016 eng d a0191-291700aFirst Report of Phytophthora uniformis and P. plurivora Causing Stem Cankers on Alnus glutinosa in Denmark0 aFirst Report of Phytophthora uniformis and P plurivora Causing S cAug-12-2017 aPDIS-09-16-12873 a

Phytophthora uniformis (Brasier & S.A. Kirk) Husson, Ioos & Aguayo, comb. nov. is an aggressive pathogen associated with root and collar rot of alder trees (Alnus spp.) in Europe (Husson et al. 2015). In summer 2016, symptomatic trees were observed in the banks of a backwater lake area of the river Gurre Å (56°1′46.24″N, 12°27′15.30″E, 29 m above sea level). Several trees displayed chlorosis, reduced leaf size, defoliation, and bleeding cankers on the base of the stem. Inspections upstream near Gurre forest failed in finding other trees with similar crown symptoms, whereas a tree with a bleeding canker was observed downstream (56°3′10.97″N, 12°26′4.40″E, 23 m above sea level). Bark from six trees in the first site and from the tree in the second site was removed from the canker area. As described in Redondo et al. (2015), pieces of 1 cm × 0.5 cm × 1 mm of necrotic cambial tissue from the infection front were plated directly into CMA-PARPBH selective medium. Growing hyphae were transferred onto V8 juice agar medium and incubated at 20°C. Isolates from the first site grew 5 mm/day and formed cottony uniform colonies. After 1 week, spherical smooth-walled oogonia often showing two-celled amphigynous antheridia developed profusely (Ø 39.6 μm; SE = 0.84). Sporangia were ellipsoid and nonpapillate, often with nested proliferation. Colonies from the second site grew 5.5 mm/day, and formed a stellate colony pattern with limited aerial mycelium. Abundant spherical (Ø 29.8 μm; SE = 0.53) oogonia with paragynous antheridia formed after 1 week. Sporangia were commonly ovoid and semipapillate. DNA was extracted from all isolates and the ITS region was amplified using the ITS4 and ITS6f primers. BLAST searches showed 99% similarity with P. uniformis sequence no. AF139367.1 for the six isolates from the first site (GenBank accession nos. KX822022 to KX822027), and 99% similarity with P. plurivora sequence no. FJ665227.1 for the isolate from the second site (KX822028). As morphological characteristics of the first six isolates corresponded to those of the P. alni species complex, primers TRP-PAU-F/-R and RAS-PAM1-F/-R (Ioos et al. 2006) were used to classify them as P. uniformis. ITS patterns from Jung and Burgess (2009) were used to classify the P. plurivora-like isolate as P. plurivora. Pathogenicity of two P. uniformis isolates and the P. plurivora isolate was confirmed by immersing 30 alder seedlings, grown in vermiculite for 3 weeks, in a zoospore suspension of each isolate adjusted to 3 × 104 zoospores ml–1 for 3 h. Seedlings were later kept in dark Eppendorf tubes in sterile water, and rewatered daily. After 10 days, mortality was 76.6 and 86.6% among those inoculated with P. uniformis, and 60% for those inoculated with P. plurivora. Surviving seedlings after 10 days displayed wilting symptoms, while seedlings immersed in water were symptomless. The roots of the dead seedlings were plated onto CMA-PARPBH selective medium. Growing hyphae were observed in all plated roots, and were transferred to V8 juice agar medium. The reisolated Phytophthora colonies were morphologically similar to P. uniformis and P. plurivora, fulfilling Koch’s postulates. Our finding raises concern about the future health of alder trees in Denmark, a country from which P. alni has not yet been reported. However, symptoms of Phytophthora disease have been observed on alder since 1995 (Thinggaard 1996). Further monitoring should investigate the extent of the outbreak.

1 aRedondo, Á.1 aThomsen, I., M.1 aOliva, J. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-09-16-1287-PDN02477nas a2200217 4500008004100000022001400041245009800055210006900153260001600222300001600238490000800254520178300262653001502045653001702060653002702077100002402104700002002128700002802148700001802176856006502194 2015 eng d a0031-949X00aWinter Conditions Correlate with Phytophthora alni Subspecies Distribution in Southern Sweden0 aWinter Conditions Correlate with Phytophthora alni Subspecies Di cJan-09-2015 a1191 - 11970 v1053 a

During the last century, the number of forest pathogen invasions has increased substantially. Environmental variables can play a crucial role in determining the establishment of invasive species. The objective of the present work was to determine the correlation between winter climatic conditions and distribution of two subspecies of the invasive forest pathogen Phytophthora alni: P. alni subspp. alni and uniformis killing black alder (Alnus glutinosa) in southern Sweden. It is known from laboratory experiments that P. alni subsp. alni is more pathogenic than P. alni subsp. uniformis, and that P. alni subsp. alni is sensitive to low temperatures and long frost periods. By studying the distribution of these two subspecies at the northern limit of the host species, we could investigate whether winter conditions can affect the geographical distribution of P. alni subsp. alni spreading northward. Sixteen major river systems of southern Sweden were systematically surveyed and isolations were performed from active cankers. The distribution of the two studied subspecies was highly correlated with winter temperature and duration of periods with heavy frost. While P. alni subsp. uniformis covered the whole range of temperatures of the host, P. alni subsp. alni was recovered in areas subjected to milder winter temperatures and shorter frost periods. Our observations suggest that winter conditions can play an important role in limiting P. alni subsp. alni establishment in cold locations, thus affecting the distribution of the different subspecies of P. alni in boreal regions.

10aAlnus spp.10ainvasiveness10aPhytophthora plurivora1 aRedondo, Miguel, A.1 aBoberg, Johanna1 aOlsson, Christer, H. B.1 aOliva, Jonàs uhttp://apsjournals.apsnet.org/doi/10.1094/PHYTO-01-15-0020-R03799nas a2200181 4500008004100000022001400041245009800055210006900153260001600222300000900238490000800247520323000255100002103485700001503506700001603521700001403537856006603551 2016 eng d a0191-291700aFirst Report of Phytophthora pseudosyringae Causing Basal Cankers on Horse Chestnut in Sweden0 aFirst Report of Phytophthora pseudosyringae Causing Basal Canker cJan-05-2016 a10240 v1003 a

Phytophthora pseudosyringae causes stem necrosis, and root and collar rot of several woody tree species (Fagus sylvatica, Alnus glutinosa, Castanea sativa, Nothofagus spp., and Quercus spp.) across Europe (Jung et al. 2003; Pintos Varela et al. 2007; Scanu and Webber 2015) and severe dieback of heathland plants such as bilberry (Vaccinium myrtillus) in the UK (Beales et al. 2010). In June 2014, a symptomatic horse chestnut tree (Aesculus hippocastanum) was detected in Sankt Jörgens Park in Gothenburg, southern Sweden (57°45′1.5″ N; 11°57′8.1″ E; elevation 22 m). The tree displayed 30% crown dieback and several tongue -shaped necrosis at the base of the stem. The outer bark over the bleeding patches was removed and small pieces of infected phloem from the margin of the necrosis were directly plated onto CMA-PARPBH selective medium (17 g/liter corn meal agar (CMA), 0.125 g/liter sodium ampicillin, 0.02 g/liter benomyl, 0.07 g/liter hymexazol, 0.1 g/liter PCNB, 0.01 g/liter primaricin, and 0.01 g/liter rifamycin) and incubated at 20°C. Growing hyphae were later transferred to V8 agar and incubated at 20°C in darkness. After 7 days, the colony reached 5.4 cm in diameter and displayed a stellate growth pattern with faint aerial mycelium. Sporangia were sympodial, semipapillate, mostly ovoid, less commonly limoniform to ellipsoid, with a length/breadth average ratio of 1.44 μm (SE = 0.03). Oogonia were 28.1 μm (SE = 0.46) in diameter, smoothly walled, spherical, and with paraginous antheridia, although some amphiginous antheridia were observed. Morphological features and growth pattern on V8 agar corresponded to those of P. pseudosyringae. DNA was extracted from mycelia and the ITS region was amplified and sequenced using the ITS4 and ITS6f primers (Cooke et al. 2000) and deposited in GenBank (Accession No. KU257470). BLAST search showed 99 to 100% identity with reference sequences of P. pseudosyringae deposited in GenBank. Under-bark inoculation with mycelium plugs was performed on 10 one-year-old excised shoots obtained from three different horse chestnut trees. Inoculated shoots were placed over autoclaved and moistened filter paper inside sterile Petri dishes and incubated at 23°C in darkness. After 14 days, the length of the lesion on inoculated shoots was significantly higher than on control shoots (8.53 mm, SE = 0.74 vs. 0.91 mm, SE = 0.93; P < 0.0001). The pathogen was reisolated from all infected shoots fulfilling Koch postulates. To our knowledge, this is the first report of P. pseudosyringae in Sweden and the first report of P. pseudosyringae causing basal cankers and dieback on horse chestnut worldwide. The number of recent reports of damage caused by P. pseudosyringae raises concerns about the potential impact of this pathogen on horse chestnut trees, widely planted as ornamentals in Sweden, as well as to natural beech and oak forests across the country.

1 aRedondo, M., Á.1 aBoberg, J.1 aStenlid, J.1 aOliva, J. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-09-15-1000-PDN03785nas a2200157 4500008004100000022001400041245009600055210006900151260001600220300001600236490000800252520327000260100001703530700001403547856006603561 2016 eng d a0191-291700aFirst Report of Phytophthora pseudosyringae Causing Stem Canker on Fagus sylvatica in Spain0 aFirst Report of Phytophthora pseudosyringae Causing Stem Canker  cJan-07-2016 a1508 - 15080 v1003 a

Phytophthora pseudosyringae T. Jung & Delatour was described in 2003 as a pathogen associated with root and collar rot of several tree species (Fagus sylvatica, Alnus glutinosa, Quercus spp.) (Jung et al. 2003), and as the causal agent of stem lesions on beech in Europe (Scanu and Webber 2016). In August 2015, a beech (Fagus sylvatica L.) tree displaying 25% crown dieback and a bleeding canker at the base of the stem was observed in a forested area used for recreational purpose in Central Pyrenees (42°36.87′ N, 0°46.09′ E, 1,546 m above sea level). Coarse sections of wood surrounding the bleeding patches were sampled and kept moist and cold for 5 days until processed. Once in the laboratory, small phloem pieces from the margin of the lesion were plated onto corn meal agar-PARPBH medium (Jeffers and Martin 1986) and incubated at 20°C. Growing hyphae were transferred to V8 agar and incubated at 20°C in darkness. Colony growth on V8 medium averaged 3.4 cm/week and had a distinct stellate pattern. Sporangia were sympodial, semipapillate, and ovoid, with a length/breadth average ratio of 1.41 μm (SE = 0.02). Oogonia were 21.9 μm (SE = 0.49) in diameter, smoothly walled, spherical, and with paraginous antheridia, although some amphiginous antheridia were observed. Morphological features and growth appearance on V8 corresponded to those reported for P. pseudosyringae (Jung et al. 2003). DNA was extracted from mycelium, and the ITS region was amplified using the ITS4 and ITS6 primers (Cooke et al. 2000). A BLAST search of the sequenced isolate (submitted to GenBank, Accession No. KU321521) showed 100% identity with P. pseudosyringae ITS sequence (AY230190) from Jung et al. (2003). An under-bark inoculation test with mycelia plugs were performed on 16 excised shoots of 1 cm of diameter obtained from four different F. sylvatica trees. After 4 weeks, inoculated shoots displayed longer necrotic lesions than control inoculations with agar (3.55 cm SE: 2.2 versus 0.59 cm SE: 2.8, P < 0.0001). The P. pseudosyringae inoculated shoots exhibited lesions that were dark red underneath the bark, whereas the control lesions did not. P. pseudosyringae, which was identified morphologically, was reisolated from 40% of the infected shoots. No reisolation of the pathogen occurred from any of the six control shoots. Although previously detected in nursery stock on sweet chestnut (Castanea sativa) (Pintos Varela et al. 2007), our report represents the first report of P. pseudosyringae naturally affecting trees in Spain, and widens the geographical distribution of this pathogen in southwestern Europe. In Spain, F. sylvatica is the third species in terms of standing volume, where it covers 400,000 ha, mainly in the Pyrenees. Our finding proves the capacity of this pathogen to establish in nature, and it raises concern over the potential impact on beech forests in Spain.

1 aRedondo, Á.1 aOliva, J. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-12-15-1497-PDN07882nas a2200157 4500008004100000245007600041210006900117260001200186300000900198490000700207520741400214100002007628700001407648700001607662856004607678 2008 eng d00aPhytophthora species causing tanoak stem cankers in southwestern Oregon0 aPhytophthora species causing tanoak stem cankers in southwestern c08/2008 a12520 v923 a

Tanoak (Lithocarpus densiflorus) is a principal host of Phytophthora ramorum, cause of sudden oak death (SOD), in the western United States (1). In the course of SOD surveys in southwestern Oregon, other Phytophthora species were encountered to be causing stem cankers on tanoak that were indistinguishable from those caused by P. ramorum. In Oregon, SOD is subject to quarantine and eradication. Aerial surveys are flown two or more times a year to locate symptomatic tanoaks, which are then examined from the ground to determine the cause of death. Isolations on selective media were attempted from all trees with stem cankers typical of Phytophthora. Phytophthora species were identified by morphological features and DNA sequencing of either internal transcribed spacer (ITS) or the mitochondrial COX spacer region. ITS sequences were compared with validated GenBank records, and COX spacer sequences were compared with known reference isolates in the OSU collection. From 2001 through 2006, Phytophthora spp. were isolated from 482 of 1,057 tanoak stem cankers sampled. P. ramorum was isolated from 359 cankers, P. nemorosa was isolated from 102 cankers, P. gonapodyides was isolated from six cankers, P. cambivora was isolated from four cankers (all A1 mating type), P. siskiyouensis was isolated from four cankers, P. pseudosyringae was isolated from two cankers, P. cinnamomi was isolated from one canker (mating type A2), and P. taxon “Pgchlamydo” was isolated from one canker. Three cankers yielded isolates that were not identified but were closely related to P. pseudosyringae based on ITS sequence. No Phytophthora spp. were cultured from the remaining cankers. One isolate from each species identified (except P. ramorum and P. pseudosyringae) was tested for pathogenicity on tanoak stems (11.4 to 16.0 cm DBH) in the field. A 5-mm-diameter plug from the margin of a V8 agar culture was placed in a hole in the bark, covered with wet cheesecloth, and sealed with aluminum foil and duct tape. Each isolate was inoculated into five different stems. Each stem received three different isolates and an agar control. After 4 weeks, bark was removed to reveal lesion development. Lesions were measured (length by width), and pieces from four points on the lesion margin were plated in selective media to reisolate. P. cambivora, P. cinnamomi, P. gonapodyides, P. nemorosa, P. siskiyouensis and P. taxon “Pgchlamydo” all caused substantial lesions in inoculated tanoak trees (average area 11.5 to 18.6 cm2). In all cases, the species used for inoculation was recovered on reisolation from lesion margins. Control inoculations caused necrotic areas averaging 0.2 cm2. Isolations from these areas were clean. Prior to the recent SOD epidemic, no species of Phytophthora were known as pathogens of tanoak. The discovery of P. ramorum as a pathogen of tanoak in California was quickly followed by the discovery that P. nemorosa and P. pseudosyringae were also associated with tanoak cankers (2). Six years of diagnostic support for survey and detection of P. ramorum in tanoak forests of southwest Oregon has revealed the occurrence, at very low frequency, of at least five additional species of Phytophthora causing stem cankers in tanoak.

1 aReeser, Paul, W1 aSutton, W1 aHansen, E M uhttp://dx.doi.org/10.1094/PDIS-92-8-1252B00615nas a2200121 4500008004100000245013500041210006900176260005700245100001700302700001800319700002000337856013600357 2010 eng d00aPhytophthora species in tanoak trees, canopy drip, soil, and streams in the sudden oak death epidemic area in southwestern Oregon.0 aPhytophthora species in tanoak trees canopy drip soil and stream aAuckland and Rotorua, New ZealandbN. Z. J. Forestry1 aReeser, Paul1 aSutton, Wendy1 aHansen, Everett uhttps://forestphytophthoras.org/references/phytophthora-species-tanoak-trees-canopy-drip-soil-and-streams-sudden-oak-death-epidemic04559nas a2200205 4500008004100000022001400041245016600055210006900221260001600290300000900306490000700315520385800322100001904180700001404199700001904213700001604232700001704248700002204265856006604287 2015 eng d a0191-291700aFirst Report of Phytophthora occultans Causing Root and Collar Rot on Ceanothus, Boxwood, Rhododendron, and Other Hosts in Horticultural Nurseries in Oregon, USA0 aFirst Report of Phytophthora occultans Causing Root and Collar R cJan-09-2015 a12820 v993 a

Dead and dying Ceanothus sanguineus, C. velutinus, and C. integerrimus plants grown in a native plant nursery in Oregon for landscape restoration were reported in 2011. Plants were wilted with stem lesions above necrotic roots. Using selective media (Hansen et al. 2012), twelve similar Phytophthora isolates were obtained. DNA sequences of the cox 1, β tubulin, and the rDNA ITS regions were generated (Hansen et al. 2012). All isolates had identical ITS sequences (GenBank KP742989), and were identical to Phytophthora occultans (Man in’t Veld et al. 2014) (JX978155) and 99% similar to P. himalsilva (HM752784) in a BLAST analysis. They were also identical to P. occultans in cox 1 and β tubulin (KR028484 and KR028483). Isolates were homothallic, with smooth 30-µm-diameter oogonia, and slightly aplerotic oospores. Antheridia were mostly paragynous. Colonies were stellate on carrot agar, growing 6 to 7 mm/d at optimum temperature (25°C). Sporangia were ovoid to irregular and papillate. Morphology and growth were consistent with P. occultans. Collections of unidentified Phytophthora spp. from the OSU Plant Clinic and from other Oregon nurseries (J. Parke et al. 2014) revealed additional isolates with similar morphology and identical DNA sequences. P. occultans was identified from boxwood (Buxus spp.), rhododendron, Gaultheria shallon, Arctostaphylos uva-ursi, and Mahonia nervosa in addition to Ceanothus spp. Two inoculation trials were conducted: (i) Healthy 1-year-old plants of C. sanguineus and C. velutinus were stem wound inoculated with two isolates of P. occultans from Ceanothus, or with sterile agar. There were 3 to 5 replications for each host and the control. The test was repeated with addition of two isolates from boxwood. (ii) Boxwood (B. sempervirens) and rhododendron (R. catawbiense Alba) were stem wound inoculated with two isolates each of P. occultans from Ceanothus and boxwood. There were four replications of each host for each isolate. All plants were incubated at 20 to 22°C. In test 1, all isolates induced stem lesions and wilting on all inoculated plants of both Ceanothus species. Wilting began in 14 days and lesions, measured at 19 days, averaged about 150 mm. There were no symptoms on control plants. In test 2, lesions developed on rhododendron stems, often girdling the stem within 12 days. Most boxwood showed no foliar symptoms or only mild yellowing, although stem lesions averaging 3.5 cm in 7 weeks were present on all plants. P. occultans was reisolated from all hosts in both tests. P. occultans was recently described from Buxus nursery stock in The Netherlands (Man in’t Veld et al. 2014), and isolates with identical DNA sequences were reported from Germany and Romania (Nechwatal et al. 2014). This is the first report from North America. It appears that a single clone of P. occultans recently has been spread widely in the nursery trade. P. occultans is similar to P. himalsilva (Vettraino et al. 2011) and to other members of the poorly defined P. citrophthora clade. Phylogenetic analysis may revise species definitions. Nursery plants grown for wildland restoration are at high risk to carry exotic Phytophthora species into vulnerable landscapes. Forest restoration specialists must demand healthy stock from nurseries.

1 aReeser, P., W.1 aSutton, W1 aHansen, E., M.1 aGoheen, E M1 aFieland, V J1 aGrünwald, N., J. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-02-15-0156-PDN00892nas a2200241 4500008004100000245008600041210006900127260012400196300001400320490004100334653001900375653002100394653002500415653002100440653001100461100001400472700001400486700001400500700002200514700002300536700002700559856006400586 2010 eng d00aPhytophthora siskiyouensis, a new species from soil and water in southwest Oregon0 aPhytophthora siskiyouensis a new species from soil and water in  aSanta Rosa, CAbU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, Albany, CAc03/2008 a439–4410 vGeneral Technical Report PSW-GTR-21410acoast live oak10ainvasive species10aPhytophthora ramorum10aSudden oak death10atanoak1 aReeser, P1 aHansen, E1 aSutton, W1 aFrankel, Susan, J1 aKliejunas, John, T1 aPalmieri, Katharine, M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr214/01614nas a2200169 4500008004100000245006400041210006400105300001000169490000800179520109600187100002001283700001801303700002301321700002101344700002001365856005901385 2011 eng d00aPhytophthora species in forest streams in Oregon and Alaska0 aPhytophthora species in forest streams in Oregon and Alaska a22-350 v1033 a

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

1 aReeser, Paul, W1 aSutton, Wendy1 aHansen, Everett, M1 aRemigi, Philippe1 aAdams, Gerry, C uhttp://www.mycologia.org/cgi/content/abstract/103/1/2200500nas a2200121 4500008004100000245008700041210006900128260001800197100001400215700001400229700001600243856011900259 2007 eng d00aPhytophthora species associated with stem cankers on tanoak in southwestern Oregon0 aPhytophthora species associated with stem cankers on tanoak in s aSanta Rosa CA1 aReeser, P1 aSutton, W1 aHansen, E M uhttps://forestphytophthoras.org/references/phytophthora-species-associated-stem-cankers-tanoak-southwestern-oregon01185nas a2200229 4500008004100000245010600041210006900147260001300216300000800229490000900237520051400246653001600760653003100776653001400807653001400821653000900835653001200844100001500856700001800871700002000889856004600909 2013 eng d00aPhytophthora pluvialis, a new species from mixed tanoak-Douglas-fir forests of western Oregon, U.S.A.0 aPhytophthora pluvialis a new species from mixed tanoakDouglasfir cMay/2013 a1-80 v8(7)3 a

A new species, Phytophthora pluvialis is described. P. pluvialis has been recovered from streams, soil and canopy drip in the mixed tanoak-Douglas-fir forest in Curry County, Oregon, and in two additional streams in other areas of western Oregon. It has been found only rarely in association with twig and stem cankers on tanoak but not with any other plant host. The earliest isolate of P. pluvialis was from soil in 2002. P. pluvialis is classified in ITS Clade 3.

10acanopy drip10aenvironmental Phytophthora10aoomycetes10arainwater10asoil10astreams1 aReeser, P.1 aSutton, Wendy1 aHansen, Everett uhttp://dx.doi.org/10.2509/naf2013.008.00701675nas a2200193 4500008004100000022001400041245006400055210006400119260001600183300001200199490000800211520110500219100002001324700001801344700002301362700002101385700002001406856005501426 2011 eng d a0027-551400aPhytophthora species in forest streams in Oregon and Alaska0 aPhytophthora species in forest streams in Oregon and Alaska cAug-01-2012 a22 - 350 v1033 a

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

1 aReeser, Paul, W1 aSutton, Wendy1 aHansen, Everett, M1 aRemigi, Philippe1 aAdams, Gerry, C uhttps://www.tandfonline.com/doi/pdf/10.3852/10-01301920nas a2200145 4500008004100000245016200041210006900203300001200272490000700284520136300291100002001654700002301674700001801697856005901715 2007 eng d00aPhytophthora siskiyouensis, a new species from soil, water, myrtlewood (Umbellularia californica) and tanoak (Lithocarpus densiflorus) in southwestern Oregon0 aPhytophthora siskiyouensis a new species from soil water myrtlew a639-6430 v993 a

An unknown Phytophthora species was recovered in southwestern Oregon from rhododendron and tanoak leaf baits used for monitoring streams and soils for the presence of Phytophthora ramorum, from a blighted shoot of myrtlewood and from tanoak bark cankers. Isolates of this species yielded ITS-DNA sequences that differed substantially from other Phytophthora sequences in GenBank. Morphological features also differed from available descriptions of known Phytophthora species. Based on the combination of unique morphology and unique ITS sequences a new species is proposed. The new species, Phytophthora siskiyouensis, is homothallic with globose to subglobose oogonia, which may be terminal, sessile or laterally intercalary. Antheridia are capitate and mostly paragynous but sometimes amphigynous. Oospores are mostly aplerotic. Sporangia are variable but commonly ovoid to reniform, with apical, subapical or lateral semipapillae (occasionally more than one). Sporangia are terminal, subterminal or occasionally intercalary on unbranched sporangiophores, with basal, subbasal or lateral attachment. Sporangia are weakly deciduous, with variable length pedicels. This combination of characters clearly separates Phytophthora siskiyouensis from other known Phytophthora species.

1 aReeser, Paul, W1 aHansen, Everett, M1 aSutton, Wendy uhttp://www.mycologia.org/cgi/content/abstract/99/5/63900421nas a2200109 4500008004100000245009200041210006900133300001200202490000700214100001700221856007300238 1923 eng d00aComparative study of Phytophthora faberi on coconut and cacao in the Philippine Islands0 aComparative study of Phytophthora faberi on coconut and cacao in a267-2840 v251 aReinking, OA uhttp://worldcocoafoundation.org/wp-content/files_mf/reinking1923.pdf02559nas a2200217 4500008004100000245017100041210006900212260001600281300001100297490000700308520180200315100002502117700002102142700001702163700002502180700001802205700001802223700002102241700001702262856006202279 2020 eng d00aDetection and spread of Phytophthora austrocedri within infected Juniperus communis woodland and diversity of co-associated Phytophthoras as revealed by metabarcoding0 aDetection and spread of Phytophthora austrocedri within infected cMay-17-2020 ae126020 v503 a

Phytophthora austrocedri is a recently invasive soilborne pathogen which is causing widespread mortality of Juniperus communis in northern Britain. The pathways by which a single genotype of P. austrocedri has spread to infect such a geographically dispersed range of woodland sites within a relatively short timeframe are unknown. This study examined the detectability of P. austrocedri in soil and water within infected J. communis woodland using qPCR to gain a better understanding of the pathogen's key mechanisms of spread. A Phytophthora metabarcoding method was also applied to investigate the wider diversity of Phytophthora species present in water at one of the sites. qPCR analyses of P. austrocedri in soil samples at a J. communis woodland exhibiting low‐to‐moderate levels of disease suggested a slow natural spread of the pathogen in soil, requiring high moisture conditions. However, the ubiquity of P. austrocedri DNA in soil samples collected across a heavily infected J. communis site suggests that once established at a site the pathogen can be spread readily in soil locally, most likely vectored by animal movements and/or human activities. The hypothesis that P. austrocedri is aerially transmitted in rainwater was not adequately proven, and an alternative hypothesis for the widespread distribution of the pathogen on J. communis in northern Britain is presented. Metabarcoding identified DNA from a diverse range of Phytophthora species in river and rainwater samples although the main target pathogen, P. austrocedri, was not amplified which disagreed with some of the qPCR findings. Possible reasons for this are discussed.

1 aRiddell, Carolyn, E.1 aDun, Heather, F.1 aElliot, Matt1 aArmstrong, April, C.1 aClark, Mhairi1 aForster, Jack1 aHedley, Pete, E.1 aGreen, Sarah uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1260202629nas a2200181 4500008004100000022001400041245011100055210006900166260001600235300001400251490000700265520203600272100001802308700001702326700001702343700001802360856006902378 2014 eng d a0191-291700aIn Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula0 aIn Situ Production of Zoospores by Five Species of Phytophthora  cJan-04-2014 a551 - 5580 v983 a

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30°C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

1 aRidge, G., A.1 aJeffers, S N1 aBridges, W C1 aWhite, S., A. uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-13-0591-RE01081nas a2200145 4500008004100000245007500041210006900116260004300185490000900228520056100237100002300798700002400821700002200845856006800867 2011 eng d00aFirst Report of Phytophthora ramorum infecting grand fir in California0 aFirst Report of Phytophthora ramorum infecting grand fir in Cali bPlant Management Networkc1 April 20110 v20113 a

Phytophthora ramorum was detected on grand fir in 2003 and 2005 in a Christmas tree plantation near Los Gatos, CA, in association with infected California bay laurel. Isolates derived from stem lesions were used to inoculate grand fir seedlings in two tests. Isolations from lesions on inoculated plants were positive for P. ramorum in both tests. This work provides the completion of Koch’s postulates to establish grand fir as a host of P. ramorum. The potential for grand fir to be infected within its native range is unknown.

1 aRiley, Kathleen, L1 aChastagner, Gary, A1 aBlomquist, Cheryl uhttp://www.plantmanagementnetwork.org/sub/php/brief/2011/grand/02155nas a2200169 4500008004100000245011000041210006900151260001600220520149000236100001701726700001901743700002101762700003001783700002801813700003101841856011301872 2016 eng d00aEffect of Brassica Biofumigant Amendments on Different Stages of the Life Cycle of Phytophthora cinnamomi0 aEffect of Brassica Biofumigant Amendments on Different Stages of cJan-05-20163 a

The oomycete plant pathogen Phytophthora cinnamomi causes a highly destructive root rot that affects numerous hosts. Integrated management strategies are needed to control P. cinnamomi in seminatural oak rangelands. We tested how biofumigation affects crucial stages of the pathogen's life cycle in vitro, in infested soils under laboratory conditions and in planta. Different genotypes of three potential biofumigant plant species (Brassica carinata, Brassica juncea, Brassica napus) were collected at different phenological stages, analysed for their glucosinolate contents, and subsequently tested. The most effective genotypes against mycelial growth and sporangial production were further tested on the viability of chlamydospores in artificially infested natural soils and in planta on Lupinus luteus, a host highly susceptible to P.cinnamomi. Brassica carinata and B. juncea genotypes inhibited mycelial growth, decreased sporangial production, and effectively inhibited the viability of chlamydospores in soil, but only B. carinata decreased disease symptoms in plants. Effective genotypes of Brassica had high levels of the glucosinolate sinigrin. Biofumigation with Brassica plants rich in sinigrin has potential to be a suitable tool for control of oak root disease caused by P. cinnamomi in Spanish oak rangeland ecosystems.

1 aRíos, Pedro1 aObergón, Sara1 ade Haro, Antonio1 aFernández-Rebollo, Pilar1 aSerrano, María-Socorro1 aSánchez, María-Esperanza uhttp://doi.wiley.com/10.1111/jph.12482http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjph.1248202584nas a2200169 4500008004100000245010400041210006900145260001600214520197200230100001402202700001702216700001802233700001602251700001702267700001702284856011302301 2016 eng d00aScreening brassicaceous plants as biofumigants for management of Phytophthora cinnamomi oak disease0 aScreening brassicaceous plants as biofumigants for management of cJan-06-20163 a

Brassicaceous plants rich in glucosinolates have been used as biofumigants for the management of soilborne pathogens. Efficacy of Brassica plant tissue has mainly been attributed to toxic isothiocyanates released upon the hydrolysis of glucosinolates. Management of Phytophthora cinnamomi, the causal agent of oak root rot in rangeland ecosystems using biofumigation, is promising, but requires further validation. The biofumigation activity of 14 brassicaceous plants was evaluated under experimental conditions. All evaluated plants rich in sinigrin suppressed (100%) the mycelial growth of P. cinnamomi, while plants rich in aromatic or other aliphatic glucosinolates had little or no suppressive effect. Simulating soil amendment in field conditions, the effects on natural soil artificially infested with P. cinnamomi chlamydospores were examined with Brassica juncea, Eruca vesicaria and Lepidium sativum, three species with different glucosinolate profiles. Only B. juncea decreased the viability of chlamydospores significantly in comparison with untreated soil only 1 day after biofumigation, whereas E. vesicaria needed 8 days to reach significance and L. sativum had no effect at all. Despite the decreases in soil inoculum, biofumigation with B. juncea did not prevent the root infections in a highly susceptible host (Lupinus luteus). However, biofumigation with plants rich in sinigrin, such as B. juncea, decreased P. cinnamomi soil inoculum under the experimental minimum threshold for oak disease expression. Although biofumigation should be considered as an effective measure to be incorporated in integrated control of the oak disease, biofumigation by itself would not be effective enough for the substantial suppression of P. cinnamomi inoculum.

1 aRíos, P.1 aObregón, S.1 aGonzález, M.1 ade Haro, A.1 aSanchez, M E1 aWoodward, S. uhttp://doi.wiley.com/10.1111/efp.12287http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fefp.1228701965nas a2200145 4500008004100000022001400041245005400055210005200109260001200161300001200173490000700185520155500192100002601747856004601773 2012 eng d a0191-291700aA Lucid key to the common species of Phytophthora0 aLucid key to the common species of Phytophthora c06/2012 a897-9030 v963 a

The Key to the Common Phytophthora species (Lucid v 3.4) is a matrix-based computerized identification key and includes important morphological and molecular characters that are useful for identification of 55 common species of Phytophthora. A set of 20 features are used to make a correct species identification. Once a culture is obtained, the user enters responses to known character state options into Lucid Player and the correct species is identified. Illustrations of each character state for a feature are included in the key. The main morphological features included in the key are: asexual structures, sexual structures, and chlamydospore, hyphae and cultural characteristics. The user can read an illustrated “Fact Sheet” on each species that includes pictures of morphological characters, disease symptoms, host range and relevant references. A cross-linked glossary of terminology is included in each fact sheet. In addition, a DNA Search function that contains a simple search of ITS and Barcode of Life (BOL, 5’ end of the cox1 gene) sequences for each species can be queried. The key was created to provide teachers, diagnosticians and regulatory personnel with easily accessible tools to distinguish common species in the genus Phytophthora based on a number of important morphological and molecular characteristics. The key is available for purchase from APS Press and should provide another useful tool for the identification of members of this destructive group of Oomycete plant pathogens.

1 aRistaino, Jean Beagle uhttp://dx.doi.org/10.1094/PDIS-08-11-063601926nas a2200169 4500008004100000245011900041210006900160300001200229490000700241520135400248100001501602700001801617700001801635700001901653700001501672856006901687 2002 eng d00aPhytophthora ramorum as the cause of extensive mortality of Quercus spp. and Lithocarpus densiflorus in California0 aPhytophthora ramorum as the cause of extensive mortality of Quer a205-2140 v863 a

A new canker disease, commonly known as sudden oak death, of Lithocarpus densiflorus, Quercus agrifolia, Q. kelloggii, and Q. parvula var. shrevei in California is shown to be caused by Phytophthora ramorum. The pathogen is a recently described species that previously was known only from Germany and the Netherlands on Rhododendron spp. and a Viburnum sp. This disease has reached epidemic proportions in forests along approximately 300 km of the central coast of California. The most consistent and diagnostic symptoms on trees are cankers that develop before foliage symptoms become evident. Cankers have brown or black discolored outer bark and seep dark red sap. Cankers occur on the trunk at the root crown up to 20 m above the ground, but do not enlarge below the soil line into the roots. Individual cankers are delimited by thin black lines in the inner bark and can be over 2 m in length. In L. densiflorus saplings, P. ramorum was isolated from branches as small as 5 mm in diameter. L. densiflorus and Q. agrifolia were inoculated with P. ramorum in the field and greenhouse, and symptoms similar to those of naturally infected trees developed. The pathogen was reisolated from the inoculated plants, which confirmed pathogenicity.

1 aRizzo, D M1 aGarbelotto, M1 aDavidson, J M1 aSlaughter, G W1 aKoike, S T uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2002.86.3.20501227nas a2200145 4500008004100000245011900041210006900160300000800229490000700237520074000244100001500984700001800999700001601017856004801033 2005 eng d00aPhytophthora ramorum: integrative research and management of an emerging pathogen in California and Oregon forests0 aPhytophthora ramorum integrative research and management of an e a3090 v433 a

Phytophthora ramorum, causal agent of sudden oak death, is an emerging plant pathogen first observed in North America associated with mortality of tanoak (Lithocarpus densiflorus) and coast live oak (Quercus agrifolia) in coastal forests of California during the mid-1990s. The pathogen is now known to occur in North America and Europe and have a host range of over 40 plant genera. Sudden oak death has become an example of unintended linkages between the horticultural industry and potential impacts on forest ecosystems. This paper examines the biology and ecology of P. ramorum in California and Oregon forests as well discussing research on the pathogen in a broader management context.

1 aRizzo, D M1 aGarbelotto, M1 aHansen, E M uhttp://www.annualreviews.org/toc/phyto/43/102935nas a2200421 4500008004100000022001400041245009900055210006900154260002900223300001600252490000700268520164200275653003501917653001801952653003201970653001302002653002702015100002302042700002502065700002302090700002202113700001802135700001602153700002102169700002502190700002402215700002402239700001702263700002502280700002102305700001702326700002502343700002002368700002402388700002202412700002402434856005502458 2011 eng d a1755-099800aDNA barcoding of oomycetes with cytochrome c oxidase subunit I and internal transcribed spacer0 aDNA barcoding of oomycetes with cytochrome c oxidase subunit I a bBlackwell Publishing Ltd a1002–10110 v113 a

Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.

10acytochrome c oxidase subunit I10aDNA barcoding10ainternal transcribed spacer10aoomycete10aspecies identification1 aRobideau, Gregg, P1 aDe Cock, Arthur, W M1 aCoffey, Michael, D1 aVoglmayr, Hermann1 aBrouwer, Henk1 aBala, Kanak1 aChitty, David, W1 aDésaulniers, Nicole1 aEggertson, Quinn, A1 aGachon, Claire, M M1 aHu, Chia-Hui1 aKüpper, Frithjof, C1 aRintoul, Tara, L1 aSarhan, Ehab1 aVerstappen, Els, C P1 aZhang, Yonghong1 aBonants, Peter, J M1 aRistaino, Jean, B1 aAndré Lévesque, C uhttp://dx.doi.org/10.1111/j.1755-0998.2011.03041.x01890nas a2200145 4500008004100000245009400041210006900135300001200204490000700216520138800223100001901611700003301630700002101663856006001684 1992 eng d00aFactors influencing the enlargement of trunk cankers of Phytophthora cinnamomi in red oak0 aFactors influencing the enlargement of trunk cankers of Phytopht a367-3740 v223 a

Development of cankers on red oak (Quercus rubra L.) caused by Phytophthora cinnamomi Rands was studied with dendrochronological techniques. Factors of variation among lesions were investigated. Lesion parameters proved to vary with the particular tree to which the lesion belonged. A discriminant factorial analysis and principal component analysis showed that this tree susceptibility was made up of two components. The first accounted for root infection and wound healing. The second concerned susceptibility to vertical spread of the pathogen in bark tissues. Relationships between (i) tree susceptibility and (ii) tree age and vigor were studied. From the occurrence of the first lesion at the collar, number and severity of lesions increased with time, following an exponential and logistic curve, respectively. A comparison of ring widths in infected and healthy trees showed that the disease had no detrimental effect on tree growth. However, annual necrosis length was positively correlated with the annual radial tree growth. The observed differences among trees could not be explained by the effects of time and vigor only. Temperature and drought were analyzed to determine their effect on lesion development. No direct effect of drought on this disease could be shown. The low cold hardiness of P. cinnamomi in the trunk was determined.

1 aRobin, Cécile1 aDesprez-Loustau, Marie-Laure1 aDelatour, Claude uhttp://www.nrcresearchpress.com/doi/abs/10.1139/x92-04800584nas a2200181 4500008004100000245012200041210006900163260001200232300001400244490000700258100001300265700001200278700001200290700001400302700001500316700001600331856005500347 2010 eng d00aRoot and aerial infections of Chamaecyparis lawsoniana by Phytophthora lateralis: a new threat for European countries0 aRoot and aerial infections of Chamaecyparis lawsoniana by Phytop c10/2011 a417–4240 v411 aRobin, C1 aPiou, D1 aFeau, N1 aDouzon, G1 aSchenck, N1 aHansen, E M uhttp://dx.doi.org/10.1111/j.1439-0329.2010.00688.x01836nas a2200193 4500008004100000022001400041245012100055210006900176260001600245520117000261100001901431700001901450700002001469700001801489700002001507700002601527700002001553856006901573 2014 eng d a0191-291700aPathogenicity of Phytophthora lateralis lineages on resistant and susceptible selections of Chamaecyparis lawsoniana0 aPathogenicity of Phytophthora lateralis lineages on resistant an cOct-10-20153 a

Phytophthora lateralis, the cause of Chamaecyparis lawsoniana root disease, was introduced in North America about 1950, and has since killed trees along roads and streams throughout the tree’s range. Recent results suggest an Asian origin for this Oomycete and four genetic lineages were identified. This raised questions for the genetic exapted resistance demonstrated in 1989 within the wild population of C. lawsoniana but with only one P. lateralis lineage. The main goal of the present research was to test the durability of the demonstrated resistance and to compare the pathogenicity of isolates representing the four lineages. No breakdown of resistance was observed in five separate tests using different inoculation techniques, resistant and susceptible C. lawsoniana trees, and seedling families. Differences in mortality and lesion length were observed between the lineages. The higher aggressiveness of isolates of the TWJ and PNW lineages and the lower aggressiveness of the TWK lineage are discussed in view of the hypotheses on the history of spread and evolutionary history of the P. lateralis lineages.

1 aRobin, Cécile1 aBrasier, Clive1 aReeser, Paul, W1 aSutton, Wendy1 aVannini, Andrea1 aVettraino, Anna Maria1 aHansen, Everett uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-14-0720-RE01872nas a2200145 4500008004100000245009100041210006900132300001200201490000700213520137300220100001901593700003301612700002101645856006001666 1992 eng d00aSpatial and temporal enlargement of trunk cankers of Phytophthora cinnamomi in red oak0 aSpatial and temporal enlargement of trunk cankers of Phytophthor a362-3660 v223 a

Phytophthora cinnamomi Rands is the agent of ink disease on northern red oak (Quercus rubra L.). Cortical cankers on the trunk are the visible symptoms. The fungus causes necrosis of the cambium and phloem, and the tree reacts by forming xylem callus curls. These features can be dated aposteriori on cross sections. The aim of this study was to describe the spatial and temporal development of cankers on cross-sectioned infected oaks. For each lesion, dates of cambium necrosis and formation of callus were recorded at different heights. The following parameters were measured for each lesion: age, height, rate of development, and length and duration of necrosis and canker. Two hundred sixty-three lesions, on 14 trees, were studied. Trees did not exhibit cankers before 9 years of age. All visible trunk cankers could be related to a collar lesion. Phytophthora cinnamomi spreads upwards and can persist for several years, being active seasonally. In this study cambium necrosis occurred preferentially during the first flush. Twenty-nine percent of the lesions were healed over at the collar after 1 year. The collar was less susceptible than the trunk. The other lesions spread rapidly in the cambium of the trunk, which was very vulnerable. They then progressively healed. Therefore, the canker progress curve was bell shaped.

1 aRobin, Cécile1 aDesprez-Loustau, Marie-Laure1 aDelatour, Claude uhttp://www.nrcresearchpress.com/doi/abs/10.1139/x92-04701923nas a2200205 4500008004100000022001400041245012400055210006900179260002600248300001400274490000700288520122200295100002701517700002101544700002201565700002101587700002301608700003101631856005501662 2005 eng d a1439-032900aSeasonal and spatial mortality patterns of holm oak seedlings in a reforested soil infected with Phytophthora cinnamomi0 aSeasonal and spatial mortality patterns of holm oak seedlings in bBlackwell Verlag GmbH a411–4220 v353 a

Summary The viability of 1-year-old holm oak (Quercus ilex) seedlings in a soil naturally infected with Phytophthora cinnamomi was studied during 2 consecutive years in a plot located in south-western Spain. In both years, total mortality during autumn and winter was not noticeable (<2.1%). In spring, mortality levels were higher (8.3–4.6%), especially the first year. A steep increase in total mortality occurred in summer, both in the first (11.4%) and second (24.2%) year, but mortality attributable to P. cinnamomi was 1.9 and 7.6%, respectively. Thus, 2 years after planting, total cumulative mortality was 43.4%, and that attributable to P. cinnamomi 9.6% (i.e. 22.1% of total mortality). Fungus-derived mortality followed a spatially aggregated pattern in the reforestation plot, suggesting a clustered distribution of the inoculum in the soil. Furthermore, mortality by P. cinnamomi was also associated with nearness of infected adult trees in the plot. Results obtained are discussed in the framework of seasonal water deficit, P. cinnamomi damage, weed competition and sanitation techniques to be used in declined holm oak stands in Spain.

1 aRodríguez-Molina, M C1 aBlanco-Santos, A1 aPalo-Núñez, E J1 aTorres-Vila, L M1 aTorres-Álvarez, E1 aSuárez-de-la-Cámara, M A uhttp://dx.doi.org/10.1111/j.1439-0329.2005.00423.x03268nas a2200193 4500008004100000022001400041245014000055210006900195260001600264300000600280490000700286520263600293100001902929700001802948700001802966700001902984700001803003856005303021 2014 eng d a1179-539500aThe use of adjuvants to improve uptake of phosphorous acid applied to Pinus radiata needles for control of foliar Phytophthora diseases0 ause of adjuvants to improve uptake of phosphorous acid applied t cJan-01-2014 a80 v443 a

Background

Phosphorous acid is being investigated as a fungicide for the management of a needle disease caused by Phytophthora pluvialis in Pinus radiata in New Zealand. However, little is known about the penetration characteristics of this fungicide into Pinus radiata foliage. This study was undertaken to determine: i) the penetration characteristics of a commercial phosphorous acid formulation, applied at 3 kg ha-1 and 12 kg ha-1 in 100 L water, into Pinus radiata foliage and, ii) the effect of four commercially available adjuvants on phosphorous acid uptake into Pinus radiata foliage. Efficacy of the best treatment was tested in vitro with two Phytophthora species, Phytophthora kernoviae and P. pluvialis.

Methods

Foliar uptake of orthophosphoric acid radio-labelled with [32P] was used to determine penetration characteristics of phosphorous acid as affected by the adjuvants tested. Needles collected from potted Pinus radiata plants sprayed with the best performing treatment were used in a detached needle assay, where treated needles were exposed to the zoospores of the Phytophthora species being tested.

Results

Uptake of the phosphorous acid formulation into Pinus radiata needles applied without adjuvants was low (3.9-6.6%) at both concentrations tested. An alcohol ethoxylate adjuvant (applied at 0.2%) and two organosilicone adjuvants (applied at 0.2%) were found to significantly increase uptake of the fungicide over that applied alone or in combination with pinolene (applied at 0.35%). Highest uptake of phosphorous acid into Pinus radiata foliage (51.6%) occurred over a period of 72 hours when the phosphorous acid was applied at the equivalent of 12 kg ha-1 with an organosilicone blend adjuvant at 0.2%. A significant reduction in lesion length on infected needles was found relative to the control when the two phosphorous acid treatments were applied with 0.2% organosilicone blend adjuvant. However, there were no significant differences in lesion length between the two treatments.

Conclusions

These results show that an organosilicone adjuvant significantly enhances uptake of phosphorous acid into Pinus radiata needles and may increase its efficacy against Phytophthora species.

1 aRolando, Carol1 aGaskin, Robyn1 aHorgan, David1 aWilliams, Nari1 aBader, Martin uhttp://www.nzjforestryscience.com/content/44/1/801968nas a2200181 4500008004100000022001400041245011600055210006900171260001600240300001600256490000800272520136300280100001801643700001701661700002201678700002101700856006501721 2016 eng d a0191-291700aComparison of Five Detection and Quantification Methods for Phytophthora ramorum in Stream and Irrigation Water0 aComparison of Five Detection and Quantification Methods for Phyt cJan-06-2016 a1202 - 12110 v1003 a

Propagules of Phytophthora ramorum, the causal agent of sudden oak death (SOD) and ramorum blight, can be recovered from infested stream and nursery irrigation runoff using baiting and filtration methods. Five detection methods, including pear and rhododendron leaf baits, Bottle O’ Bait, filtration, and quantitative polymerase chain reaction (qPCR) performed on zoospores trapped on a filter were compared simultaneously in laboratory assays using lab or creek water spiked with known quantities of P. ramorum zoospores. The detection threshold for each method was determined and methods that could be used to quantify zoospore inoculum were identified. Filtration and qPCR were the most sensitive at detecting low levels of zoospores, followed by wounded rhododendron leaves, rhododendron leaf disks, and pear baits. Filtration, qPCR, and leaf disks were able to quantify P. ramorum zoospores ranging from 2 to 451 direct-plate CFU/liter while wounded leaves and pear baits appeared to be better at detection rather than quantification. The ability to detect and quantify P. ramorum inoculum in water will assist scientists, regulatory agencies, and nursery personnel in assessing the risk of spreading P. ramorum in nurseries and landscape sites where untreated infested water is used for irrigation.

1 aRollins, Lucy1 aCoats, Katie1 aElliott, Marianne1 aChastagner, Gary uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-11-15-1380-RE02242nas a2200169 4500008004100000245008700041210006900128260001600197300001000213520166800223100002101891700002001912700002301932700002801955700001901983856007002002 2016 eng d00aPotential risk of occurrence of Phytophthora alni in forests of the Czech Republic0 aPotential risk of occurrence of Phytophthora alni in forests of  cJun-06-2018 a1 - 53 a

Phytophthora alni is an invasive organism that causes root and collar rot in alders, which significantly damages the forest and riparian vegetation of alder trees in Central and Western Europe. In the Czech Republic, this pathogen was first confirmed in 2001, and since then it has been gradually spreading from the west to the east. Here, we applied a model of potential distribution that estimates the level and spatial variability of the pathogen occurrence and spread risk for Czech Republic forests to target the early detection and control the further invasion of P. alni in this region. Our predictions are based on a rigorous statistical analysis of data obtained from field survey as well as available geodatabases. We used two sets of predictor variables describing (i) the forest stands and (ii) neighbourhood of the stands, and generalized linear modelling with forward stepwise selection of predictors. The results of statistical analysis showed the significant effect of the area of the forest stand, forest vegetation zone, presence of watercourse and area of alder stands in the neighbourhood on the probability of occurrence of P. alni in the study region. The map derived based on the final model shows the potential risk of occurrence and impact of P. alni in forests of the Czech Republic as classified on a five-point scale ranging from very low risk for alder stands with a low level of likely invasion to very sensitive alder stands with high probability of pathogen occurrence and high levels of damage. This is a unique output not only for the Czech Republic but also throughout Europe.

1 aRomportl, Dušan1 aChumanová, Eva1 aHavrdová, Ludmila1 aPešková, Vítězslava1 aČerný, Karel uhttp://www.tandfonline.com/doi/full/10.1080/17445647.2016.119899603855nas a2200157 4500008004100000022001400041245011300055210006900168260001600237300001400253490000700267520330900274100002203583700002203605856007003627 2014 eng d a0191-291700aFirst Report of Root and Stem Rot Caused by Phytophthora tentaculata on Mimulus aurantiacus in North America0 aFirst Report of Root and Stem Rot Caused by Phytophthora tentacu cJan-07-2014 a996 - 9960 v983 a

Sticky monkey flower plant, Mimulus aurantiacus (Phrymaceae), is a small, perennial shrub that is widely distributed throughout California, especially in coastal and disturbed habitats. It is also found in native plantings in parks and landscapes. In October 2012, nearly all the M. aurantiacus plants grown in a Monterey County, CA nursery for a restoration project were stunted and had dull, yellowish leaves. Roots and stem collars had necrotic, sunken lesions with few feeder roots. Thirty percent of the plants had died. Samples of diseased plants were sent to the CDFA-PPDC Lab and tested positive for Phytophthora sp. using the Agdia ELISA Phytophthora kit (Agdia, Elkhart, IN). A Phytophthora sp. was consistently isolated from the tissue on corn meal agar-PARP (CMA-PARP) (2). Sporangia were spherical to ovoid, papillate to bipapillate and 17 to 42.5 (avg. 27.5) × 12 to 35 (avg. 22.9) μm, with a length/breadth ratio of 1.2:1. Chlamydospores, which were spherical, terminal to intercalary, thin walled and 27.5 to 40 μm, and hyphal swellings formed on CMA-PARP. Spherical oospores, 25 to 36 μm, with primarily paragynous antheridia formed readily on V8 juice agar. rDNA sequences of the internal transcribed spacer (ITS) region of the isolates (GenBank KF667505), amplified using primers ITS1 and ITS4, were 100% identical to Phytophthora tentaculata (CBS 552.96, GenBank AF266775) by a BLAST query (1,3). To assess pathogenicity, exposed root crowns of three 3.78-liter potted M. aurantiacus plants were inoculated with 20 ml of zoospore suspension (2 × 104 ml−1). Plants were maintained in a 23°C growth chamber with a 12-h photoperiod and watered daily. Sterile water was applied to the exposed crowns of three control plants. At 2 weeks, all inoculated plants were wilted with chlorotic foliage. After 3 weeks, the cortical tissue of the crowns and roots was discolored and sloughing and P. tentaculata was recovered on CMA-PARP. P. tentaculata did not grow from the asymptomatic control plants. Inoculations were repeated with similar results. P. tentaculata is a homothallic species in Phytophthora clade 1 that causes crown, root, and stalk rot of nursery plants in Europe and China (1,4). A USDA PERAL analysis lists it as one of the top 5 Phytophthora species of concern to the United States (4). Genera infected with P. tentaculata include Apium, Aucklandia, Chicorium, Chrysanthemum, Delphinium, Gerbera, Lavandula, Santolina, Origanum, and Verbena (4). To our knowledge, this is the first report of P. tentaculata in North America. The source of inoculum of P. tentaculata in California remains unknown. The nursery used seed and cuttings of M. aurantiacus from nearby native areas for propagation, and P. tentaculata was not found in neighboring plant hosts or by baiting soil and water at the nursery. All infected M. aurantiacus material was destroyed. The presence of P. tentaculata in California nurseries could have serious economic impacts on the nursery industry and environmental impacts on susceptible native hosts, if spread into the wildlands.

1 aRooney-Latham, S.1 aBlomquist, C., L. uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-09-13-1002-PDN01594nas a2200145 4500008004100000245008900041210006900130260002900199520105400228100002701282700002501309700002001334700002301354856007101377 2009 eng d00aCollar rot on Italian alder trees in California caused by Phytophthora siskiyouensis0 aCollar rot on Italian alder trees in California caused by Phytop bPlant Management Network3 a

In November 2006, trees of Italian alder (Alnus cordata) were observed declining in association with bleeding trunk cankers in a commercial landscape in Foster City, CA. A species of Phytophthora was isolated on PARP selective medium from the leading edge of the cankers. The Phytophthora species was homothallic with primarily paragynous antheridia and had oospores that were mostly globose and aplerotic. Sporangia were produced from mycelia on plugs of carrot piece agar in soil extraction solution and were semi-papillate and ovoid to ellipsoid in shape. The intergenic transcribed spacer region of rDNA from an alder isolate matched with 100% identity to isolates in GenBank of Phytophthora siskiyouensis, a recently described species associated with tanoak and found in the soil and waterways of coastal Oregon. Pathogenicity was tested on young alder trees growing in pots. Pathogenicity was confirmed on Italian alder trees and potential pathogenicity was demonstrated on red and white alder trees.

1 aRooney-Latham, Suzanne1 aBlomquist, Cheryl, L1 aPastalka, Tomas1 aCostello, Laurence uhttp://www.plantmanagementnetwork.org/sub/php/research/2009/alder/01839nas a2200157 4500008004100000245010700041210006900148260009100217490002900308520120100337100002101538700001901559700001601578700001801594856006901612 2007 eng d00aFirst report of Phytophthora siskiyouensis causing disease on Italian alder in Foster City, California0 aFirst report of Phytophthora siskiyouensis causing disease on It aSan Diego, CaliforniabAPS Press, American Phytopathological SocietycJuly 28–August0 vPhytopathology 97: S101.3 a

Phytophthora species cause cankers on the stems of many forest and landscape trees. In November of 2006, Italian alder trees, Alnus cordata, were reported to be dying with symptoms of bleeding cankers located at the base of the stem. The trees were located in a business development outside of a library in Foster City, California. Several of the trees had already been removed as hazardous. Successful isolations were made at the leading edge of the canker from the wood cambium interface onto PARP selective medium. A homothallic Phytophthora with primarily paragynous antheridia grew out in the media. The sporangia, produced easily on carrot agar plugs in soil water were ovoid to ellipsoid in shape. Oospores were mostly globose and aplerotic. The intergenic transcribed spacer region of rDNA of the oomycete matched with 100% identity to Phytophthora siskiyouensis, a pathogen associated with tan oak and also found in the soil and water in coastal Oregon. Pathogenicity experiments were conducted on Italian, red and white alder. This Phytophthora may be endemic to California. Foster City shares a marine- influenced climate with coastal Oregon.

1 aRooney-Latham, S1 aBlomquist, C L1 aPastalka, T1 aCostello, L R uhttp://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO.2007.97.7.S101570nas a2200193 4500008004100000022001400041245013900055210006900194260001600263300001200279490000700291520092500298100002201223700002201245700001601267700001801283700002001301856005501321 2015 eng d a1522-833900aFirst detection in the US: new plant pathogen, Phytophthora tentaculata, in native plant nurseries and restoration sites in California0 aFirst detection in the US new plant pathogen Phytophthora tentac cJan-03-2015 a23 - 270 v163 a

Phytophthora tentaculata Kröber & Marwitz (Pythiaceae) has been detected in several native plant nurseries in 4 California counties and in restoration sites on orange sticky monkey flower (Diplacus aurantiacus (W. Curtis) Jeps. subsp. aurantiacus [Scrophulariaceae]), toyon (Heteromeles arbutifolia (Lindl.) M. Roem. [Rosaceae]), coffeeberry (Frangula californica (Eschsch.) A. Gray [Rhamnaceae]), and sage (Salvia spp. L. [Lamiaceae]). These findings are the first detections of P. tentaculata in the US and the first ever on these host plants. Phytophthora species are a known problem in horticultural nurseries, but little attention has been placed on native plant or restoration nurseries. The potential for plant pathogens to be outplanted along with native plant nursery stock is very high, posing a threat to neighboring forests.

1 aRooney-Latham, S.1 aBlomquist, C., L.1 aSwiecki, T.1 aBernhardt, E.1 aFrankel, S., J. uhttp://npj.uwpress.org/cgi/doi/10.3368/npj.16.1.2300337nas a2200109 4500008004100000245003800041210003800079300001200117490000600129100001800135856007400153 1917 eng d00aStudies of the genus Phytophthora0 aStudies of the genus Phytophthora a233-2760 v81 aRosenbaum, J. uhttps://forestphytophthoras.org/references/studies-genus-phytophthora02442nas a2200145 4500008004100000022001400041245011800055210006900173260001600242520189900258100002902157700002702186700001702213856006602230 2020 eng d a0191-291700aSporulation potential of Phytophthora ramorum differs among common California plant species in the Big Sur region0 aSporulation potential of Phytophthora ramorum differs among comm cNov-17-20203 a

Sudden oak death (SOD), caused by the generalist pathogen Phytophthora ramorum, has profoundly impacted California coastal ecosystems. SOD has largely been treated as a two-host system, with Umbellularia californica as the most transmissive host, Notholithocarpus densiflorus less so, and remaining species as epidemiologically unimportant. However, this understanding of transmission potential primarily stems from observational field studies rather than direct measurements on the diverse assemblage of plant species. Here, we formally quantify the sporulation potential of common plant species inhabiting SOD-endemic ecosystems on the California coast in the Big Sur region. This study allows us to better understand the pathogen’s basic biology, trajectory of SOD in a changing environment, and how the entire host community contributes to disease risk. Leaves were inoculated in a controlled laboratory environment and assessed for production of sporangia and chlamydospores, the infectious and resistant propagules, respectively. P. ramorum was capable of infecting every species in our study and almost all species produced spores to some extent. Sporangia production was greatest in N. densiflorus and U. californica and the difference was insignificant. Even though other species produced much less, quantities were non-zero. Thus, additional species may play a previously unrecognized role in local transmission. Chlamydospore production was highest in Acer macrophyllum and Ceanothus oliganthus, raising questions about the role they play in pathogen persistence. Lesion size did not consistently correlate with the production of either sporangia or chlamydospores. Overall, we achieved an empirical foundation to better understand how community composition affects transmission of P. ramorum.

1 aRosenthal, Lisa, Micaela1 aFajardo, Sebastian, N.1 aRizzo, David uhttps://apsjournals.apsnet.org/doi/10.1094/PDIS-03-20-0485-RE00587nas a2200169 4500008004100000022001400041245011500055210006900170260001300239300001200252490000700264100001500271700001600286700001800302700001600320856008100336 1994 eng d a0378-112700aSpatial pattern of Austrocedrus chilensis wilting and the scope of autocorrelation analysis in natural forests0 aSpatial pattern of Austrocedrus chilensis wilting and the scope  cAUG 1994 a273-2790 v671 aRosso, P H1 aBaccalá, N1 aHavrylenko, M1 aFontenla, S uhttp://dx.doi.org.proxy.library.oregonstate.edu/10.1016/0378-1127(94)90022-100463nas a2200133 4500008004100000022005500041245003000096210002800126260007700154100001400231700001600245700001900261856004900280 1987 eng d aForest Pest Management Report No. R6 FPM PR 010 9100aPort-Orford-cedar disease0 aPortOrfordcedar disease bU.S. Department of Agriculture, Forest Service, Pacific Northwest Region1 aRoth, L F1 aHarvey, R D1 aKliejunas, J T uhttp://www.fs.fed.us/r6/nr/fid/fidls/poc.htm01929nas a2200133 4500008004100000245007100041210006900112300001600181490000700197520146800204100001901672700002301691856008101714 1966 eng d00aPhytophthora cinnamomi, an unlikely threat to Douglas-fir forestry0 aPhytophthora cinnamomi an unlikely threat to Douglasfir forestry a147-159(13)0 v123 a

Phytophthora cinnamomi has damaged forests around the world in regions with mild climates. Its pathogenesis on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in southern Europe and southeastern United States suggested a potential threat to Douglas-fir forests of the Pacific Coast. Concern increased in 1950 with discovery of P. cinnamomi in nurseries growing ornamentals and in landscape plantings in western Oregon and Washington and research was undertaken to evaluate the threat. A temperature of 60° F was found necessary for infection. While summer soil temperatures on south exposures are above 60° F most of the time from June to October soil moisture is continuously below field capacity and too dry for infection. On north exposures summer soil moisture is adequate but temperatures are too low; 60° F is reached for only a few hours near the first of August. Forest soils of western Oregon are generally too dry for infection during the summer. The fall rains provide necessary moisture but concurrently depress temperatures below the critical 60° F. Adverse soil temperature and moisture influence disease by impeding infection rather than reducing survival of P. cinnamomi. The disease in ornamentals is sustained by summer irrigation of warm locations such as the south side of buildings. The data show that P. cinnamomi is unlikely to become a problem in forests of the Pacific Northwest.

1 aRoth, Lewis, F1 aKuhlman, George, E uhttp://www.ingentaconnect.com/content/saf/fs/1966/00000012/00000002/art0000502161nas a2200157 4500008004100000022001300041245008800054210006900142260001600211300001400227490000700241520165900248100001801907700002701925856005101952 1997 eng d a0378112700aSurvey and virulence of fungi occurring on diseased Acacia mearnsii in South Africa0 aSurvey and virulence of fungi occurring on diseased Acacia mearn cJan-12-1997 a327 - 3360 v993 a

Various disease symptoms occur on Acacia mearnsii in South Africa, of which black butt, on older trees, is the most common. Other less commonly reported symptoms include gummosis, cracks, discoloured lesions and die-back. These diseases are of unknown aetiology. During a 2-year period, a survey of diseases on A. mearnsii was conducted in two major commercial wattle-growing areas of South Africa. Samples were collected from all symptomatic tissue on randomly selected trees in each area. A wide range of fungi were isolated, including species of Phytophthora, Seiridium, Sphaeropsis, Fusarium, Diplodia, Ceratocystis and Botryosphaeria. Of these, Phytophthora spp. were isolated only from basal lesions and soil, whereas the Diplodia and Fusarium spp. were the most frequently isolated from diseased tissue on aboveground parts of trees. Phytophthora parasitica and Ceratocystis albofundus, which are well-known pathogens of A. mearnsii, were excluded from the pathogenicity tests. All other fungi isolated, and particularly those belonging to genera that are known plant pathogens, were used in pathogenicity tests to determine their possible role in diseases. For each isolate, 20 saplings were inoculated in the field, and the resultant lesion lengths were measured. Only the Phytophthora spp., Botryosphaeria sp. and Sphaeropsis sp. produced noticeable lesions. From the surveys and pathogenicity tests, it is clear that many fungi are associated with diseases of A. mearnsii, and that these deserve further study.

1 aRoux, Jolanda1 aWingfield, Michael, J. uhttps://doi.org/10.1016/s0378-1127(97)00110-2 02673nas a2200181 4500008004100000022001400041245006700055210006700122260001200189300001400201490000700215520210700222100002002329700001602349700002802365700002002393856007802413 2008 eng d a0282-758100aIrrigation water and Phytophthora cactorum in a forest nursery0 aIrrigation water and Phytophthora cactorum in a forest nursery c10/2008 a404 - 4110 v233 a

Phytophthora cactorum (Lebert and Cohn) J. Schröt is known to cause stem lesions on Betula pendula Roth in Finnish nurseries. It has been suggested that irrigation water may be one source of infection. Therefore, P. cactorum was baited from pond water used for irrigation and direct isolations were made from necrotic stem lesions in a forest nursery during the years 2004–2006. Morphological characteristics, as well as sequencing of the β-tubulin gene and ITS1 region, confirmed the isolates as P. cactorum. The pathogen was present in the pond every year, but no diseased seedlings were found in 2005. The cultural and morphological characteristics showed high variation among the isolates, but it was not possible to identify the origins of the isolates according to them. In random amplified microsatellite (RAMS) analysis and DNA sequencing, the isolates from the pond and from the stem lesions were genetically similar, and the tested isolates were pathogenic. The results indicate that irrigation water is one source of stem lesion disease, and the microbe can overwinter in the pond. Two separate forms of the β-tubulin gene were detected in all the studied isolates, suggesting that the P. cactorum here carries two β-tubulin gene loci in its genome.

1 aRytkönen, Anna1 aLilja, Arja1 aPetäistö, Raija-Liisa1 aHantula, Jarkko uhttp://www.tandfonline.com/doi/abs/10.1080/02827580802419034#.UqfxDo25Ibg