02351nas a2200181 4500008004100000022001400041245009100055210006900146260002900215300001400244490000700258520178200265100001602047700001402063700002402077700001302101856005502114 2012 eng d a1439-032900aInvolvement of Phytophthora spp. in chestnut decline in the Black Sea region of Turkey0 aInvolvement of Phytophthora spp in chestnut decline in the Black bBlackwell Publishing Ltd a377–3860 v423 a

Chestnut blight caused by Cryphonectria parasitica is a serious disease of Castanea sativa in the Black Sea region of Turkey. During disease surveys, dieback and decline symptoms were observed on trees without apparent blight and ink disease symptoms. Black necroses, similar to those caused by Phytophthora infections, were noted on some of the chestnut coppices and saplings in one nursery in Ordu and led to an investigation into this disease complex. Only symptomatic plants showing dieback symptoms were investigated. Soil samples together with fine roots were collected from two directions, north and north-east, approximately 150 cm away from the main stems. Phytophthora spp. were baited with young chestnut leaves. Three Phytophthora spp., P. cambivora, P. cinnamomi and P. plurivora, were identified from 12 soil samples collected from 73 locations, while from the nurseries, only P. cinnamomi was obtained. Phytophthora cinnamomi was the most common species, obtained from seven locations in five provinces and from four nurseries having similar symptoms mentioned above in different locations. Phytophthora cambivora and P. plurivora were less frequently obtained, from three to two stands, respectively. Phytophthora cinnamomi and P. cambivora were the most aggressive species when inoculated at the stem base on 3-year-old chestnut saplings, killing six saplings of eight inoculated in 2 months. The three Phytophthora species were first recorded on chestnut in Black sea region of Turkey with the limited samples investigated in a large area about 150 000 ha chestnut forest.

1 aAkıllı, S1 aSerçe, U1 aKatırcıoğlu, Y Z1 aMaden, S uhttp://dx.doi.org/10.1111/j.1439-0329.2012.00770.x01968nas a2200193 4500008004100000022001400041245009300055210006900148260002900217300001400246490000700260520137500267100001301642700001401655700001701669700001401686700001901700856005501719 2010 eng d a1439-032900aInvolvement of Phytophthora species in white oak (Quercus alba) decline in southern Ohio0 aInvolvement of Phytophthora species in white oak Quercus alba de bBlackwell Publishing Ltd a430–4420 v403 a

This study was initiated to investigate the possible role of Phytophthora species in white oak decline (Quercus alba) in southern Ohio at Scioto Trail State Forest. Surveys demonstrated the presence of four species of Phytophthora including one novel species. By far, the most common species was P. cinnamomi; P. citricola and P. cambivora were isolated infrequently. In few instances, P. cinnamomi was isolated from fine roots and necroses on larger roots. No special pattern of incidence was found, but P. cinnamomi was more commonly isolated from greater Integrated Moisture Index values suggesting moist lower bottomlands favour this Phytophthora species. When tree crown condition was examined relative to the presence of Phytophthora, no significant association was found. However, roots of declining P. cinnamomi-infested trees had 2.5 times less fine roots than non-infested and healthy trees, which was significantly different. The population densities of P. cinnamomi from declining trees were significantly greater than from healthy trees, suggesting increased pathogen activity that has the potential to cause dieback and decline and possibly the cause of a reduced fine root amount found on declining trees.

1 aBalci, Y1 aLong, R P1 aMansfield, M1 aBalser, D1 aMacDonald, W L uhttp://dx.doi.org/10.1111/j.1439-0329.2009.00617.x00489nas a2200121 4500008004100000245013800041210006900179300001200248490000700260100001600267700001500283856006900298 2000 eng d00aIncidence of Phytophthora root rot of Fraser fir in North Carolina and sensitivity of isolates of Phytophthora cinnamomi to metalaxyl0 aIncidence of Phytophthora root rot of Fraser fir in North Caroli a661-6640 v841 aBenson, D M1 aGrand, L F uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2000.84.6.66100972nas a2200145 4500008004100000245006300041210005900104520052000163100001600683700001600699700001600715700001400731700001700745856006400762 2001 eng d00aThe impact of plant diseases on world chocolate production0 aimpact of plant diseases on world chocolate production3 a

Many factors contribute to a decline in production of cocoa beans worldwide. Plant diseases such as black pod, witches’ broom, and frosty pod rot are major components of the decline in production. Plant pathologists and microbiologists must discover and devise means to reduce disease losses and to save chocolate for the enthusiastic consumers of the world. This review discusses the major disease of cacao and their effect on world production.

1 aBowers, J H1 aBailey, B A1 aHebbar, P K1 aSanogo, S1 aLumsden, R D uhttp://www.plantmanagementnetwork.org/pub/php/review/cacao/02485nas a2200253 4500008004100000022001400041245012000055210006900175260002600244300001400270490000700284520170700291653002501998653001302023653002802036653001202064653001902076653002102095100001402116700001402130700001702144700001502161856005502176 2005 eng d a1365-305900aIn vitro leaf inoculation studies as an indication of tree foliage susceptibility to Phytophthora ramorum in the UK0 aIn vitro leaf inoculation studies as an indication of tree folia bBlackwell Science Ltd a512–5210 v543 a

Leaves of 11 coniferous and 23 broad-leaved tree species important to UK forestry were tested for their susceptibility to the quarantine pathogen Phytophthora ramorum using a detached leaf assay. Two European and two USA isolates were used. Wounded and unwounded leaves were dipped in zoospore suspensions during summer; conifers were also tested in winter. Successful infection of tissue and amount of necrosis were assessed. Highly susceptible broad-leaved hosts included Aesculus hippocastanum, Fraxinus excelsior, Quercus ilex, Ulmus procera and, to a lesser extent, Castanea sativa, Q. cerris and Q. petraea, together with Umbellularia californica and rhododendrons. Acer pseudoplatanus, Alnus glutinosa, Carpinus betulus, Corylus avellana, Fagus sylvatica, Prunus avium, Q. robur, Q. rubra and Q. suber showed consistently low susceptibility. Conifer species including Abies procera, Picea abies, P. sitchensis, Pseudotsuga menziesii, Sequoia sempervirens and Tsuga heterophylla were also susceptible. Pseudotsuga menziesii and A. procera were severely affected. Pinus contorta, P. nigra var. maritima and P. sylvestris were virtually resistant, while Taxus baccata was only slightly affected. Increased necrosis was apparent on leaves that were wounded prior to inoculation. These results extend the known range of trees that P. ramorum is able to attack and confirm its relative host-nonspecificity.

10abroad-leaved species10aconifers10adetached leaf dip assay10afoliage10aforest species10aSudden oak death1 aDenman, S1 aKirk, S A1 aBrasier, C M1 aWebber, JF uhttp://dx.doi.org/10.1111/j.1365-3059.2005.01243.x01448nas a2200193 4500008004100000245011800041210006900159260001800228300001400246490000700260520077400267100001501041700001701056700001901073700002001092700001301112700001601125856011301141 2015 eng d00aAn improved method for qPCR detection of three Phytophthora spp. in forest and woodland soils in northern Britain0 aimproved method for qPCR detection of three Phytophthora spp in  cDecember 2015 a537–5390 v453 a

Summary

Using TaqMan qPCR assays, DNA of P. ramorum, P. kernoviae and P. austrocedri was detected in 500 g soil samples collected from twelve infected forest and woodland sites in northern Britain. Phytophthora DNA was also amplified in soil adhering to boots after walking transects along footpaths or animal trails. At two sites, Phytophthora DNA was detected in soil over a 4-year period following removal of infected hosts. This new method enabling assessment of larger quantities of soil demonstrates the contamination risk of these pathogens in soil at infected sites and improves our understanding of the mechanisms of persistence and spread.

1 aElliot, M.1 aSchlenzig, A1 aHarris, C., M.1 aMeagher, T., R.1 aGreen, S1 aBelbahri, L uhttp://doi.wiley.com/10.1111/efp.12224http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fefp.1222401957nas a2200145 4500008004100000022001300041245010500054210006900159300001200228490000700240520140400247100001701651700001401668856012901682 1980 eng d a0031949X00aInteraction of light and sterol on sporangium and chlamydospore production by Phytophthora lateralis0 aInteraction of light and sterol on sporangium and chlamydospore  a650-6540 v703 a

Chlamydospore production by Phytophthora lateralis was most abundant in V8 broth with 20 μg/ml β-sitosterol, and maximum sporangium production occurred with 10 μg/ml. Growth (dry weight) was not enhanced by sterol concentrations ranging from 1 to 200 μg/ml. Cultures grown on V8 sterol agar or broth, and illuminated (680 μW cm2, combined Blacklight Blue and Cool White fluorescent lamps) either continuously or 12 hr daily, produced at least four times as many sporangia as were produced by cultures in the dark on sterol media, or in the light or dark on media not amended with sterol. Chlamydospores were produced most abundantly in the dark on V8 sterol agar or broth, with production greatly reduced by continuous or 12 hr of light daily. Chlamydospore production was suppressed by all light intensities tested (85, 170, 340, 680 μW cm2) compared with production in the dark. Few chlamydospores formed in cultures on media without sterol, whether incubated in the light or dark. Growth (dry weight or colony size) was not affected by illumination. None of numerous regimes of diurnal temperature cycles enhanced sporulation more than constant temperatures. Optimal sporangium production requires incubation on media with sterol at 14-16 C in the light; optimal chlamydospore production requires incubation at 24-25 C in the dark on media with sterol.

1 aEnglander, L1 aRoth, L F uhttps://forestphytophthoras.org/references/interaction-light-and-sterol-sporangium-and-chlamydospore-production-phytophthora02518nas a2200229 4500008004100000022001400041245010700055210006900162260003800231300001400269490000700283520178600290653002302076653002402099653002102123653002702144100001802171700001502189700001402204700001502218856005502233 2011 eng d a1365-305900aInfectivity and sporulation potential of Phytophthora kernoviae to select North American native plants0 aInfectivity and sporulation potential of Phytophthora kernoviae  bBlackwell Publishing Ltdc04/2012 a224–2330 v613 a

Phytophthora kernoviae exhibits comparable epidemiology to Phytophthora ramorum in invaded UK woodlands. Because both pathogens have an overlapping geographic range in the UK and often concurrently invade the same site, it is speculated that P. kernoviae may also invade North American (NA) forests threatened by P. ramorum, the cause of Sudden Oak Death. This paper addresses the susceptibility of select NA plants to P. kernoviae, including measures of disease incidence and severity on wounded and unwounded foliage. The potential for pathogen transmission and survival was investigated by assessing sporangia and oospore production in infected tissues. Detached leaves of Rhododendron macrophyllum, Rhododendron occidentale and Umbellularia californica, and excised roots of U. californica and R. occidentale were inoculated with P. kernoviae and percent lesion area was determined after 6 days. Leaves were then surface sterilized and misted to stimulate sporulation and after 24 h sporangia production was assessed. The incidence of symptomless infections and sporulation were recorded. All NA native plants tested were susceptible to P. kernoviae and supported sporangia production; roots of U. californica and R. occidentale were both susceptible to P. kernoviae and supported sporangia production. Oospore production was also observed in U. californica roots. The results highlight the vulnerability of select NA native plants to infection by P. kernoviae, suggest that symptomless infections may thwart pathogen detection, and underscore the importance of implementing a proactive and adaptive biosecurity plan.

10aforest biosecurity10ahost susceptibility10ainvasive disease10aPhytophthora kernoviae1 aFichtner, E J1 aRizzo, D M1 aKirk, S A1 aWebber, JF uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02506.x02685nas a2200193 4500008004100000245011100041210006900152260001600221300001100237490000700248520204500255100001902300700002602319700001802345700002402363700001902387700002302406856006202429 2020 eng d00aImpact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae0 aImpact of weather variables and season on sporulation of Phytoph cMar-03-2020 ae125880 v503 a

Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.

1 aFraser, Stuart1 aGomez-Gallego, Mireia1 aGardner, Judy1 aBulman, Lindsay, S.1 aDenman, Sandra1 aWilliams, Nari, M. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1258802153nas a2200145 4500008004100000245011700041210006900158300001200227490000700239520165700246100001501903700001901918700001501937856005501952 1999 eng d00aThe impact of Phytophthora disease on riparian populations of common alder (Alnus glutinosa) in southern Britain0 aimpact of Phytophthora disease on riparian populations of common a39–500 v293 a

Summary In 1994 a survey was established to obtain information on Phytophthora disease of common alder (Alnus glutinosa) on the riverbanks of southern England and east Wales. Within an area of 70 000 km2 63 observation plots were set up on stretches of river over 8 m wide. Average alder densities varied widely in different parts of the survey area; from 0.7 to 22.2 trees per 100 m of river. From the density figures and data on the total length of rivers over 8 m wide within the survey area, it was estimated that there were approximately 585 000 alder trees growing on the banks of such rivers. In 1994 3.9% of the trees showed crown symptoms of Phytophthora disease, and an additional 1.2% of trees were dead, although not all of these had been killed by Phytophthora. The disease occurred widely through the survey area with an indication that the highest percentage of affected trees was to be found in the south-east of England. Subsequent surveys showed that the combined percentage of symptomatic and dead trees rose to 6.0% in 1995 and to 7.9% in 1996. In the latter year, for an alder population of 585 000 trees, this would correspond to 32 800 symptomatic and 13 500 dead trees. The percentage of trees showing symptoms was seven times as high in trees growing within 1 m of the riverbank as in trees growing between 1 and 10 m of the bank. An examination of the relationships between disease incidence and various indices of water pollution revealed a positive association with total oxidized nitrogen. These results are discussed in relation to the biology and possible origin of the disease.

1 aGibbs, J N1 aLipscombe, M A1 aPeace, A J uhttp://dx.doi.org/10.1046/j.1439-0329.1999.00129.x02527nas a2200241 4500008004100000245014600041210006900187260001300256300001100269490000800280520171900288653001302007653002302020653002502043653002002068653001602088100002102104700002502125700002202150700002302172700002802195856006202223 2020 eng d00aThe influence of time, soil moisture and exogenous factors on the survival potential of oospores and chlamydospores of Phytophthora cinnamomi0 ainfluence of time soil moisture and exogenous factors on the sur cNov/2020 ae126370 vn/a3 a

The mode of persistence of Phytophthora cinnamomi, a highly aggressive soil- and water-borne pathogen, remains unclear. This study investigated the survival of viable oospores and chlamydospores of P. cinnamomi when present as free propagules in untreated soil, or in soil subject to four exogenous treatments: smoke water, fish emulsion and two fungicides (ridomil and furalaxyl). The exogenous treatments were applied under moist and dry soil conditions. Spore viability was determined by the thiazolyl blue tetrazolium bromide (MTT) staining technique, with a qPCR assay used to compare general patterns of decline. Over 96% of oospores lost viability over a period of 48 weeks irrespective of soil moisture conditions. The mean percentage viability for oospores decreased from 91% at time zero to 72, 35, 20 and 1% after 6, 12, 24 and 48 weeks, respectively. Reduction in viability of chlamydospores was more rapid than oospores, with viability declining from 92% to zero after 12 weeks. There was no significant difference between untreated soil and the exogenous treatments. The RNA-based qPCR assay indicated a strong presence of viable oospores of P. cinnamomi up to week 12 for moist soil and week 3 for dry soil, but thereafter failed to detect RNA even though viable oospores could be detected by MTT staining. Based on the MTT staining, this study indicated that viability of P. cinnamomi oospores may be entirely lost within 1 year and that of chlamydospores within 3 months for the soil type tested. Therefore, oospores and chlamydospores when existing as free propagules in soil appear unlikely to be involved in the long-term survival of P. cinnamomi.

10adormancy10along-term survival10aphytophthora dieback10aspore viability10avital stain1 aGyeltshen, Jamba1 aDunstan, William, A.1 aGrigg, Andrew, H.1 aBurgess, Treena, I1 aHardy, Giles, E. St. J. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1263700499nas a2200145 4500008004100000022001300041245006800054210006700122260001400189300001200203490000700215100001400222700001600236856010100252 1984 eng d a0191291700aImproved method for isolating Phytophthora lateralis from soil.0 aImproved method for isolating Phytophthora lateralis from soil cJune 1984 a517-5190 v681 aHamm, P B1 aHansen, E M uhttps://forestphytophthoras.org/references/improved-method-isolating-phytophthora-lateralis-soil00522nas a2200133 4500008004100000245009000041210006900131260002000200300001200220490000700232100001400239700001600253856011900269 1987 eng d00aIdentification of Phytophthora spp. known to attack conifers in the Pacific Northwest0 aIdentification of Phytophthora spp known to attack conifers in t bWSU Pressc1987 a103-1090 v611 aHamm, P B1 aHansen, E M uhttps://forestphytophthoras.org/references/identification-phytophthora-spp-known-attack-conifers-pacific-northwest00606nas a2200157 4500008004100000022001400041245011200055210006900167300001200236490000700248100001600255700001400271700001400285700001400299856013500313 1979 eng d a0032-081100aIsolation, incidence and management of Phytophthora in forest tree nurseries in the Pacific Northwest [USA]0 aIsolation incidence and management of Phytophthora in forest tre a607-6110 v631 aHansen, E M1 aHamm, P B1 aJulis, AJ1 aRoth, L F uhttps://forestphytophthoras.org/references/isolation-incidence-and-management-phytophthora-forest-tree-nurseries-pacific-northwest02344nas a2200145 4500008004100000245006800041210006800109260001600177300001100193490000700204520188700211100002102098700002102119856005802140 2019 eng d00aInsights into the potential host range of Phytophthora foliorum0 aInsights into the potential host range of Phytophthora foliorum cSep-18-2019 ae125560 v493 a

During a survey for Phytophthora ramorum undertaken in north‐west Scotland in early 2016, Phytophthora foliorum was found infecting foliage of the invasive shrub Rhododendron ponticum. Prior to this, P. foliorum had only been reported from foliage of hybrid azaleas in nurseries in California and Tennessee and from azalea plants in an ornamental nursery in Spain. No other hosts were known, and much of the behaviour of P. foliorum remained enigmatic. The species is classified in Phytophthora Clade 8c, with closest relatives, P. ramorum and Phytophthora lateralis, both of which are highly damaging tree pathogens. To explore the threat that P. foliorum might pose to trees, its growth–temperature responses on agar media and ability to cause lesions in the living bark of various hosts were contrasted with the behaviours of P. ramorum and P. lateralis. Phytophthora foliorum proved faster growing and more tolerant of temperature extremes than the other Phytophthora species. Comparisons of bark colonization initially focussed on R. ponticum and larch species Larix decidua and Larix kaempferi as all three are significant hosts of P. ramorum in the UK. Further experiments included another P. ramorum host, Fagus sylvatica (European beech), and the main host of P. lateralis, Chamaecyparis lawsoniana (Lawson cypress). Findings suggested that as well as being a significant pathogen of R. ponticum, damage caused by P. foliorum to both species of larch and beech was very similar to that of the EU1 lineage of P. ramorum, although growth in host tissue was also influenced by season.

1 aHarris, Anna, R.1 aWebber, Joan, F. uhttps://onlinelibrary.wiley.com/doi/10.1111/efp.1255602503nas a2200205 4500008004100000245013100041210006900172260001200241300001400253520178100267100001502048700001202063700001602075700001502091700001602106700001902122700001302141700001602154856012702170 2013 eng d00aIdentification of Phytophthora species baited and isolated from forest soil and streams in northwestern Yunnan province, China0 aIdentification of Phytophthora species baited and isolated from  c01/2013 an/a - n/a3 a

Phytophthora species were surveyed by collecting soil samples and placing bait leaves in selected streams during June–October in the years 2005, 2006 and 2010 at three sites in oak forests in Diqing Tibetan Autonomous Prefecture of NW Yunnan province, China. Seventy-three isolates of Phytophthora spp. were recovered from 135 baited leaf samples and 81 soil samples. Eight Phytophthora species were identified by observation of morphological features and ITS1-5.8S-ITS2 rDNA sequence analysis. The eight taxa included two well-known species P. gonapodyides and P. cryptogea, two recently described species P. gregata and P. plurivora, two named but as yet undescribed taxa, P. taxon PgChlamydo and P. taxon Salixsoil, and two previously unrecognized species, Phytophthora sp.1 and P. sp.2. The most numerous species, P. taxon PgChlamydo, and the second most abundant species, P. taxon Salixsoil, were recovered at all three sites. Phytophthora cryptogea was detected only once at site Nixi. Phytophthora gregata and P. sp.2 were isolated from a stream only at site Bitahai, while the other three species were each found at two sites. Phylogenetic analysis revealed that the isolates belonged to three ITS clades, one species including six isolates in clade 2, six species including 66 isolates in clade 6 and one species in clade 8. There was a relatively rich species and genetic diversity of Phytophthora detected in the investigated regions where the forest biotic and abiotic factors affecting the growth and evolution of Phytophthora populations were diverse.

1 aHuai, W -x1 aTian, G1 aHansen, E M1 aZhao, W -x1 aGoheen, E M1 aGrünwald, N J1 aCheng, C1 aBelbahri, L uhttps://forestphytophthoras.org/references/identification-phytophthora-species-baited-and-isolated-forest-soil-and-streams00651nas a2200193 4500008004100000022001400041245009500055210006900150300001400219490000700233653001400240100001200254700001600266700002200282700001900304700001900323700001500342856010000357 2005 eng d a0269-915X00aInvolvement of Phytophthora species in the decline of European beech in Europe and the USA0 aInvolvement of Phytophthora species in the decline of European b a159 - 1660 v1910adetection1 aJung, T1 aHudler, G W1 aJensen-Tracy, S L1 aGriffiths, H M1 aFleischmann, F1 aOsswald, W uhttp://www.sciencedirect.com/science/article/B7XMS-4R10WR2-5/2/37dcb413ca17af3b17f99e6101570c6502230nas a2200169 4500008004100000022001400041245012800055210006900183260001200252300001400264490000700278520159700285100001201882700001601894700001501910856013501925 2000 eng d a0032-086200aInvolvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease0 aInvolvement of soilborne Phytophthora species in Central Europea c12/2000 a706 - 7180 v493 a

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

1 aJung, T1 aBlaschke, H1 aOßwald, W uhttps://forestphytophthoras.org/references/involvement-soilborne-phytophthora-species-central-european-oak-decline-and-effect-site02289nas a2200157 4500008004100000245013300041210006900174260001600243300001600259490000700275520163300282100001701915700001901932700001901951856016101970 2015 eng d00aIn planta detection used to define the distribution of the European lineages of Phytophthora ramorum on larch (Larix ) in the UK0 aIn planta detection used to define the distribution of the Europ cJan-10-2015 a1168 - 11750 v643 a

Two genetically distinct evolutionary lineages of the oomycete pathogen Phytophthora ramorum are responsible for the major epidemic on larch (Larix spp.) in the UK: EU1 (historically widespread) and the recently identified EU2 (reported only from Northern Ireland and a small area in southwest Scotland). Methods for lineage discrimination have required pure cultures of P. ramorum but, as the pathogen is challenging to isolate from infected larch tissue, only limited data have been available on the distribution of EU2. In this study a protocol was developed to determine the lineage of P. ramorum in infected larch tissue without the need for isolation. The protocol was applied to 134 UK samples collected during 2013–14. In addition, lineage testing was applied to over 300 P. ramorum isolates cultured from a wide range of hosts between 2002 and 2012. Combined data confirmed that EU2 is restricted to Northern Ireland and a small area of southwest Scotland where it is the dominant lineage. There was no evidence of EU2 spread into England and Wales where only EU1 was found. However, EU2 was more widely distributed in southern and eastern parts of Scotland than previously reported. Furthermore, EU1 and EU2 were detected <10 km apart in larch plantations. This study provides the first reports of natural EU2 infection on European larch (Larix decidua), hybrid larch (Larix × eurolepis), beech (Fagus sylvatica), noble fir (Abies procera) and western hemlock (Tsuga heterophylla).

1 aKing, K., M.1 aHarris, A., R.1 aWebber, J., F. uhttp://doi.wiley.com/10.1111/ppa.2015.64.issue-5http://doi.wiley.com/10.1111/ppa.12345http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fppa.1234502336nas a2200181 4500008004100000022001300041245016200054210006900216260001600285300001200301490000700313520165900320100002201979700002402001700001902025700002302044856008702067 2017 eng d a1754504800aInterspecific interactions between the Sudden Oak Death pathogen Phytophthora ramorum and two sympatric Phytophthora species in varying ecological conditions0 aInterspecific interactions between the Sudden Oak Death pathogen cAug-08-2017 a86 - 960 v283 a

Even when introduced invasive pathogens lack their natural predators or competitors, they must still interact with other organisms in their introduced range. Sudden Oak Death (SOD), caused by Phytophthora ramorum (Oomycota), is an introduced disease causing large-scale tree mortality. Two additional Phytophthora species, Phytophthora nemorosa and Phytophthora pseudosyringae, cause significantly lower oak mortality, yet they also commonly colonize leaves of Umbellularia californica, the major transmissive host of SOD in California. We combined field surveys and inoculation experiments to understand disease prevalence dynamics and competitive interactions among these pathogen species. Despite the broader geographic distribution of P. nemorosa with respect to that of P. ramorum, our results suggest that P. nemorosa exhibits a narrower ecological amplitude and, in any given region, occupies fewer sites than P. ramorum. Our results additionally suggest that, perhaps due to priority effects, P. nemorosa can persist at levels comparable to those of P. ramorum in ecologically suitable plots when climate favors P. ramorum dormancy. However, P. ramorum prevalence increases to levels higher than those of the competing species when abundant rainfall triggers its sporulation. Understanding the determinants and outcomes of competition between these species has important implications for understanding the epidemiology and possible control strategies for Sudden Oak Death.

1 aKozanitas, Melina1 aOsmundson, Todd, W.1 aLinzer, Rachel1 aGarbelotto, Matteo uhttps://www.sciencedirect.com/science/article/abs/pii/S1754504817300600?via%3Dihub02379nas a2200241 4500008004100000245011500041210006900156260003800225300001200263490000700275520158700282653002801869653002501897653002501922653002601947653001401973100001801987700001702005700002002022700001902042700001902061856005702080 2009 eng d00aIsolation, identification and characterization of Phytophthora katsurae, causing chestnut ink disease in Korea0 aIsolation identification and characterization of Phytophthora ka bKorean Society of Plant Pathology a121-1270 v253 a

Since July 2005, survey of chestnut ink disease was carried out in chestnut stands located at southern parts of Korea. Dead chestnut trees showing inky ooze on necrotic trunks were found in two different locations. In order to isolate and identify the causal fungus, infected tissues and soil samples around dead or dying trees were collected and placed on Phytophthora-selective medium. Rhododendron and chestnut tree leaves were used as a bait to isolate the fungus from soil samples by attracting zoospores in soil suspensions. On V-8 culture medium, the isolates produced homothallic oogonia with protuberances (34.0-46.2×21.9-26.7㎛) abundantly, but did not produced sporangia. Mass production of sporangia was possible by immersing agar plugs with actively growing mycelium in the creek water at 18oC for 3 days. Sporangia were papillate, and ovoid to obpyriform (17.0-38.9×14.6-29.2㎛) in shape. Comparison of the ITS sequences revealed that the isolates had 100% identity to the P. katsurae isolates from Japan and New Zealand and 99.6% identity to other P. katsurae isolates. All of the examined isolates from Korea were completely identical to each other in ITS sequence. Numerous sporangia were formed in filtered as well as unfiltered creek water, but no sporangia formed in sterilized distilled water. Light induced sporangia formation, but has no influence on oospore formation. Amendments of β-sitosterol in culture media have no significant effect on mycelial growth but significantly stimulate oospore and sporangia formation.

10aamphigynous antheridium10achestnut ink disease10ahomothallic oogonium10aPhytophthora katsurae10asporangia1 aLee, Jong Kyu1 aJo, Jong Won1 aShin, Keum Chul1 aLee, Sang Hyun1 aLee, Sang Yong uhttp://www.dbpia.co.kr/view/ar_view.asp?arid=120777002133nas a2200157 4500008004100000245009600041210006900137300001400206490000700220520162300227100002101850700002001871700001801891700001701909856004901926 2012 eng d00aIdentification and detection of Phytophthora: reviewing our progress, identifying our needs0 aIdentification and detection of Phytophthora reviewing our progr a1080-11030 v963 a

With the increased attention given to the genus Phytophthora in the last decade in response to the ecological and economic impact of several invasive species (such as P. ramorum, P. kernoviae, and P. alni), there has been a significant increase in the number of described species. In part, this is due to the extensive surveys in historically underexplored ecosystems (e.g., forest and stream ecosystems) undertaken to determine the spread of invasive species and the involvement of Phytophthora species in forest decline worldwide (e.g., oak decline). The past decade has seen an approximate doubling in the number of described species within the genus Phytophthora, and the number will likely continue to increase as more surveys are completed and greater attention is devoted to clarifying phylogenetic relationships and delineating boundaries in species complexes. The development of molecular resources, the availability of credible sequence databases to simplify identification of new species, and the sequencing of several genomes have provided a solid framework to gain a better understanding of the biology, diversity, and taxonomic relationships within the genus. This information is much needed considering the impact invasive or exotic Phytophthora species have had on natural ecosystems and the regulatory issues associated with their management. While this work is improving our ability to identify species based on phylogenetic grouping, it has also revealed that the genus has a much greater diversity than previously appreciated.

1 aMartin, Frank, N1 aAbad, Gloria, Z1 aBalci, Yilmaz1 aIvors, Kelly uhttp://dx.doi.org/10.1094/PDIS-12-11-1036-FE01950nas a2200157 4500008004100000022001300041245009700054210006900151260001100220300001600231490000700247520142100254100002301675700002301698856007101721 1994 eng d a0953756200aIsozyme diversity in Phytophthora palmivora: evidence for a southeast Asian centre of origin0 aIsozyme diversity in Phytophthora palmivora evidence for a south c9/1994 a1035 - 10430 v983 a

Isozyme and morphological data were obtained for 93 isolates of P. palmivora and six described as P. arecae. Sporangial shape for both species ranged from spherical to ellipsoid with a high percentage of sporangia predominantly ellipsoid with a broad base and a short occluded pedicel less than 5 m in length. Fourteen enzymes stained in starch gels yielding 17 putative loci, 11 of which were monomorphic, the remainder being polymorphic (GPI, HEX2, IDH1, MDH1, PEP and SOD). Phosphoglucose isomerase (GPI) and isocitric dehydrogenase (IDH1) were the most variable loci. Isozyme analysis of the 99 isolates revealed 18 electrophoretic types (ETs). Isolates of P. arecae clustered with P. palmivora in ET7 and ET8, the most common ETs found in P. palmivora. Considerable genetic diversity was found amongst P. palmivora isolates from coconut (Cocos nucifera) with 8 ETs, durian (Durio zibethinus) with 5 ETs and other non-cacao hosts from Indonesia, Malaysia, Philippines and Thailand. Since coconut and durian are indigenous to the region, a southeast Asian origin for P. palmivora seems probable. Finally, since no significant differences were found in either morphology or isozymes between isolates of P. palmivora and P. arecae, this study provides definitive evidence that the two species are conspecific.

1 aMchau, Godwin, R A1 aCoffey, Michael, D uhttp://www.sciencedirect.com/science/article/pii/S095375620980430902459nas a2200145 4500008004100000245010100041210006900142260002600211300001400237490000700251520189400258100001702152700001902169856012502188 2005 eng d00aInfluence of site factors on the impact of Phytophthora cinnamomi in cork oak stands in Portugal0 aInfluence of site factors on the impact of Phytophthora cinnamom bBlackwell Verlag GmbH a145–1620 v353 a

Although decline of cork (Quercus suber) and holm oak trees (Quercus rotundifolia) has been described in Portugal in the late years of the 19th century, its development has become a motive of high concern during the last two decades. The presence of Phytophthora cinnamomi in cork and holm oak stands was surveyed in four different regions of the country (Trás-os-Montes, Alentejo, Ribatejo and Algarve) during 1995–98. Tree decline severity, sudden death and site characteristics were assessed in 56 sites representing varied conditions. The pathogen was isolated from oak roots and rhizosphere samples in 27 of those places. Other plant species from natural vegetation were sampled in three active disease centres. This survey showed that 56% of the surveyed species of shrub flora were infected with P. cinnamomi, which was detected mainly on species belonging to the families Ericaceae, Cistaceae and Leguminosae. Recovery of P. cinnamomi was more frequent in shallow soils (Leptosols and complex Leptosols and Luvisols). These soils are more common in the south (Algarve), where decline has a high impact. Soils with low fertility and low mineral nutrient levels, particularly phosphorus, seemed to favour infection. Site aspect and topographic tree situation were also evaluated. Sites facing south showed higher occurrence of P. cinnamomi, which was also more frequent in slopes and valleys than on hilltops. In Algarve, a relationship could be established between the crown status and the presence of P. cinnamomi in roots and rhizosphere. Different morphotypes of P. cinnamomi could be distinguished in vitro, and their occurrence in the field was correlated with particular site characteristics. Further research needs and management strategies to limit the extension of the disease are discussed.

1 aMoreira, A C1 aMartins, J M S uhttps://forestphytophthoras.org/references/influence-site-factors-impact-phytophthora-cinnamomi-cork-oak-stands-portugal02022nas a2200217 4500008004100000022001300041245012500054210006900179260001100248300001400259490000700273520135100280100002101631700001301652700001301665700001401678700001501692700001301707700001301720856007101733 2004 eng d a0261219400aImpact of removing diseased pods on cocoa black pod caused by Phytophthora megakarya and on cocoa production in Cameroon0 aImpact of removing diseased pods on cocoa black pod caused by Ph c5/2004 a415 - 4240 v233 a

Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon. Field experiments were carried out over two successive years in two smallholders’ plots of cocoa trees, in order to assess the impact of diseased pod removal (phytosanitary pod removal) on disease progress, total production and final harvest. The generalized linear mixed model proved to be the most appropriate for comparing the two treatments (without and with pod removal) set up in a randomized complete block design. Removing diseased pods helped to reduce the black pod rate by 22% and 31% in the two sites in the first year, and by 9% and 11% in the second year, compared to a plot in which no preventive control measures were taken. The rate of cherelle (very young pod) appearance was also higher when pod removal was carried out. Total production was higher in the plots with pod removal, but the difference between the two treatments was not significant. This study allowed an evaluation of the respective roles of primary and secondary inoculum in the spread of the disease. The cultural practice of phytosanitary pod removal was found to be a potentially efficient control method. However, it would need to be associated with other control methods to establish an integrated management system for cocoa farmers.

1 aNdoumbe-Nkeng, M1 aCilas, C1 aNyemb, E1 aNyasse, S1 aBieysse, D1 aFlori, A1 aSache, I uhttp://www.sciencedirect.com/science/article/pii/S026121940300237001723nas a2200157 4500008004100000245011500041210006900156300001200225490000700237520112500244100001501369700001401384700001601398700001901414856013201433 1976 eng d00aIdentity and pathogenicity of species of Phytophthora causing root rot of Douglas-fir in the Pacific Northwest0 aIdentity and pathogenicity of species of Phytophthora causing ro a710-7140 v663 a

Three species of Phytophthora previously unreported from Douglas-fir were isolated along with P. cinnamomi from diseased trees from forest nurseries, forest outplanting sites, and seedling storage facilities in western Oregon and Washington. Two species were identified as P. cryptogea and P. drechsleri on the basis of sporangial and colony morphology, temperature-growth relations, and by comparisons with isolates of known identity. A third species, designated Phytophthora sp. 1, did not correspond to any previously described species. Phytophthora cinnamomi and P. cryptogea were highly virulent on dormant and growing Douglas-fir seedlings in greenhouse tests. Phytophthora drechsleri and Phytophthora sp. 1 appeared to be less virulent. Phytophthora cryptogea, P. drechsleri and Phytophthora sp. 1 are similar to P. lateralis, a destructive pathogen of Port-Orford-cedar, in growth at low temperatures and should therefore be regarded as potentially dangerous forest pathogens in cool, moist sites.

1 aPratt, R G1 aRoth, L F1 aHansen, E M1 aOstrofsky, W D uhttps://forestphytophthoras.org/references/identity-and-pathogenicity-species-phytophthora-causing-root-rot-douglas-fir-pacific02629nas 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-RE02673nas 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#.UqfxDo25Ibg02257nas a2200145 4500008004100000245010200041210006900143300001200212490000700224520170800231100001501939700001201954700001801966856012701984 2007 eng d00aInvolvement of Phytophthora species in the decline of beech Fagus sylvatica in Wallonia (Belgium)0 aInvolvement of Phytophthora species in the decline of beech Fagu a879-85.0 v723 a

During the last decade, typical symptoms of Phytophthora diseases were observed in beech stands of several European countries. The main symptoms were the presence of bleeding cankers on the stem, a low crown density as well as the yellowing of foliage and the small size of leaves. Several species of Phytophthora, such as Phytophthora citricola, P. cambivora and P. cactorum, were reported as the causal agents. In order to evaluate the implication of the different Phytophthora species in beech decline in the southern part of Belgium (Wallonia), a monitoring was undertaken with the help of managers of public and private forests. Phytophthora strains isolated from beech of different stands as well as from soil were characterized through morphological and molecular analyses (PCR-RFLP of ITS). All the isolated strains were identified as P. cambivora, except for one strain whose identification is ongoing. Molecular analysis was also directly applied to necrosed tissues of bleeding beeches and enabled the detection of additional cases. All positive cases exhibited a profile characteristic of the species P. cambivora, except for one of the sampled trees showing a different Phytophthora profile also corresponding to the unidentified isolated strain. Identification of the Phytophthora species linked to this different RFLP profile is also ongoing. Both complementation types (A1 and A2) of P. cambivora were identified, sometimes in the same sampling site. Ornamented oogonia characteristic of this species were produced by pairing A1 and A2 strains isolated from the same site.

1 aSchmitz, S1 aZini, J1 aChandelier, A uhttps://forestphytophthoras.org/references/involvement-phytophthora-species-decline-beech-fagus-sylvatica-wallonia-belgium00710nas a2200169 4500008004100000245012300041210006900164260011100233300001200344490003200356100001700388700001700405700001700422700001900439700001800458856006400476 2008 eng d00aIncreasing distance from California bay reduces the risk and severity of Phytophthora ramorum canker in coast live oak0 aIncreasing distance from California bay reduces the risk and sev aSanta Rosa, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station a181-1940 vGen. Tech. Rep. PSW-GTR-2141 aSwiecki, T J1 aBernhardt, E1 aFrankel, S J1 aKliejunas, J T1 aPalmieri, K M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr214/02000nas a2200169 4500008004100000022001400041245012600055210006900181300000600250520139100256653001801647100002601665700002101691700002601712700002101738856007101759 2012 eng d a1754-504800aInhibition of Phytophthora species by secondary metabolites produced by the dark septate endophyte Phialocephala europaea0 aInhibition of Phytophthora species by secondary metabolites prod a-3 a

Dark septate fungal root endophytes of the Phialocephala fortinii s.l.–Acephala applanata species complex (PAC) are widely distributed throughout the temperate and subtropical regions of the Northern Hemisphere. Previous studies have shown that some PAC members are pathogenic, others suppress oomycete root pathogens and some have no obvious effect on their Norway spruce (Picea abies) host. The activity of 85 PAC isolates against Phytophthora citricola s.l. was investigated by co-culture on plates. We identified a strain of Phialocephala europaea that significantly reduced the growth of P. citricola in vitro. Characterization of its extracellular metabolites resulted in the identification of four major compounds, sclerin, sclerolide, sclerotinin A, and sclerotinin B. These compounds are known for their positive as well as negative effects on plant growth. We found that sclerin and sclerotinin inhibited the growth of P. citricola in vitro at 150 μg ml-1 (\~{}1 mM). This is the first report of their production by Phialocephala and of activity of these compounds against an oomycete. Therefore, our data suggest that some PAC might reduce disease resulting from P. citricola by the production of antibiotics and plant growth promoting metabolites.

10aSclerotinin A1 aTellenbach, Christoph1 aSumarah, Mark, W1 aGrünig, Christoph, R1 aMiller, David, J uhttp://www.sciencedirect.com/science/article/pii/S175450481200128601997nas a2200157 4500008004100000245010700041210006900148260001200217300001400229490000800243520145800251100002001709700002101729700002301750856006601773 2013 eng d00aInoculum density relationships for infection of some eastern US forest species by Phytophthora ramorum0 aInoculum density relationships for infection of some eastern US  c09/2013 a595–6030 v1613 a
Our objectives were to establish inoculum density relationships between P. ramorum and selected hosts using detached leaf and whole-plant inoculations. Young plants and detached leaves of Quercus prinus (Chestnut oak), Q. rubra (Northern red oak), Acer rubrum (red maple), Kalmia latifolia (mountain laurel) and Rhododendron ‘Cunningham's White’ were dip-inoculated with varying numbers of P. ramorum sporangia, and the total number of diseased and healthy leaves recorded following incubation at 20°C and 100% relative humidity. Calibration threshold estimates for obtaining 50% infected leaves based on linear analysis ranged from 36 to 750 sporangia/ml for the five hosts. Half-life (LD50) estimates (the number of spores for which the per cent of diseased leaves reaches 50% of its total) from asymptotic regression analysis ranged from 94 to 319 sporangia/ml. Statistically significant differences (P = 0.0076) were observed among hosts in per cent infection in response to increased inoculum density. Inoculum threshold estimates based on studies with detached leaves were comparable to those obtained using whole plants. The results provide estimates of inoculum levels necessary to cause disease on these five P. ramorum hosts and will be useful in disease prediction and for development of pest risk assessments.
1 aTooley, Paul, W1 aBrowning, Marsha1 aLeighty, Robert, M uhttp://onlinelibrary.wiley.com/doi/10.1111/jph.12107/abstract00891nas a2200133 4500008004100000245006200041210006100103300001400164490000700178520044400185100001500629700001900644856009400663 2001 eng d00aInk disease in chestnuts: impact on the European chestnut0 aInk disease in chestnuts impact on the European chestnut a345–3500 v763 aA resurgence of ink disease in chestnuts in Europe has been noted since the end of the last century. This lethal disease is currently limiting the establishment of new groves and is threatening the survival of old ones. This paper discusses the impact of the disease and current knowledge about its aetiology and epidemiology. It gives information on the existing variability in tolerance in selected hybrid clones and in wild populations.1 aVannini, A1 aVettraino, A M uhttps://forestphytophthoras.org/references/ink-disease-chestnuts-impact-european-chestnut02312nas 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.x00467nas 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-guinea01898nas 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-RE02292nas a2200157 4500008004100000245012400041210006900165300001200234490000700246520174600253100001601999700001902015700001602034700001902050856006502069 2009 eng d00aIdentification and frequency of Phytophthora species associated with foliar diseases in California ornamental nurseries0 aIdentification and frequency of Phytophthora species associated  a883-8900 v933 a

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. ‘Pgchlamydo’, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen–host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

1 aYakabe, L E1 aBlomquist, C L1 aThomas, S L1 aMacDonald, J D uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-088302361nas a2200181 4500008004100000022001400041245012400055210006900179260001600248300001400264490000700278520175500285100001602040700002202056700001602078700001902094856006602113 2009 eng d a0191-291700aIdentification and Frequency of Phytophthora Species Associated with Foliar Diseases in California Ornamental Nurseries0 aIdentification and Frequency of Phytophthora Species Associated  cJan-09-2009 a883 - 8900 v933 a

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. ‘Pgchlamydo’, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen–host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

1 aYakabe, L E1 aBlomquist, C., L.1 aThomas, S L1 aMacDonald, J D uhttps://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-0883