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Phytophthora pseudosyringae causes stem necrosis and collar rot of deciduous tree species (Quercus spp., Fagus silvatica, and Alnus glutinosa) in several European countries (1,2). In November 2006, we received diseased Castanea sativa seedlings from a nursery in Galicia (northwest Spain). These plants had tongue-shaped necroses of the inner bark and cambium. Reddish, sunken lesions occurred on the surface of the bark, either in the stem base or higher on the stem. Tissue from the leading edge of the lesions was transferred to a selective V8 agar medium (4) and incubated for 7 days at 20°C in the dark. A Phytophthora sp. was isolated, transferred to cornmeal agar (CMA) and V8 agar, and incubated in the dark. Colonies were appressed with stellate to rosaceous growth patterns on CMA and stellate, limited aerial mycelium on V8 agar. Growth on V8 occurred from 2 to 25°C with an optimum at 20°C and a radial growth rate of 4.5 mm per day at 20°C. Chains of inflated spherical to deltoid hyphal swellings with radiating hyphae were abundantly produced in water (2). Chlamydospores were not observed on agar media. The deciduous, sympodial, semipapillate, rarely bipapillate sporangia with pedicels had a length/breadth average ratio of 1.55. Oogonia, antheridia, and oospores were produced within a single culture. Oogonia were spherical and smooth walled, antheridia were predominantly paraginous, but some were amphyginous, and oospores were plerotic that turned golden yellow with age (2). Internal transcribed spacer (ITS)-rDNA and mitochondrial DNA (mtDNA) regions were amplified by nested-PCR and sequenced with DNA extracted from mycelium. The amplicon sizes obtained were similar to those reported for P. pseudosyringae (2,3). DNA sequences showed 99 to 100% homology with those previously identified as P. pseudosyringae and deposited in GenBank. Pathogenicity of the isolate was confirmed by inoculating 10 C. sativa seedlings, as well as three detached leaves from each of another 10 young plants growing in containers. For the seedlings, one shallow cut was made into the bark on the main stem. A colonized agar plug was inserted beneath the flap that was sealed with Parafilm. Unwounded and wounded detached leaves of C. sativa were dipped into a zoospore aqueous suspension (1 × 105 zoospores ml–1) for 10 s., seedlings and leaves were incubated at 20°C and 95% humidity for 60 and 7 days, respectively. After 7 days, foliar lesions that developed exceeded 25 mm, and the pathogen was consistently reisolated. Leaves inoculated with sterile water did not develop symptoms. On inoculated seedlings, the external surface of the bark was reddish and sunken. Stem lesions progressed bidirectionally from the wound. P. pseudosyringae was recovered from inoculated seedlings but not from controls. On the basis of its unique combination of morphological and physiological characters, pathogenicity, and ITS and mtDNA sequences, the Phytophthora isolated from chestnut was identified as P. pseudosyringae. To our knowledge, this is the first report of P. pseudosyringae on C. sativa in Spain. References: (1) EPPO Reporting Service. Online publication. No. 10 2005/162, 2005. (2) T. Jung et al. Mycol. Res. 107:772, 2003. (3) F. N. Martin et al. Phytopathology 94:621, 2004. (4) C. Pintos Varela et al. Plant. Dis. 87:1396, 2003.

Phytophthora alni, a soil- and waterborne pathogen, causes aggressive root and collar rot on riparian alder populations (1,2,4). The disease has been described from several European countries with a destructive impact in Great Britain (1,2). All European alder species and the red alder (Alnus rubra) are highly susceptible. P. alni has multiple variants that have been placed in three subspecies: P. alni subsp. alni, P. alni subsp. uniformis, and P. alni subsp. multiformis (1). In July 2009, a survey of symptoms of Phytophthora rot from A. glutinosa at 20 riparian stands along the Avia River in Galicia (northwest Spain) was conducted. Affected trees showed symptoms of Phytophthora rot including abnormally small, sparse, and yellowish foliage, dieback in the canopy, necroses of the inner bark and cambium, and bleeding cankers on the trunks (2,4). Phytophthora spp. were baited from saturated rhizosphere soil and watercourses using oak leaflets (4). Roots and tissue from fresh active inner bark lesions were transferred to selective medium V8-PARPH agar (4) and incubated for 7 days at 22°C in the dark. A Phytophthora sp. was isolated, transferred to carrot agar (CA), and incubated in the dark. Colonies were appressed, often irregular in outline, and with limited aerial mycelium (1). Growth on CA occurred from 4 to 31°C with optimum growth at 23 to 25°C. Chlamydospores were not observed. Ellipsoid, nonpapillate, noncaducous sporangia had a length/breadth average ratio of 1.4. Nesting and extended internal proliferation occurred. Oogonia, antheridia, and oospores were abundantly produced in a single culture. Oogonia with tapered stalks were spherical (mature oogonia 38 to 50 μm in diameter) and some had ornamented walls or bullate protuberances (1,2). Antheridia were large, amphigynous, and predominantly two-celled (23 to 37 × 16 to 23 μm). Oospores were plerotic. Distorted comma-shaped or smaller oogonia and aborted oospores were observed (1). Amplification of DNA was accomplished by using sequence-characterized amplification region-PCR primers (3). The amplicon sizes obtained were identical to P. alni subsp. alni (3). Internal transcribed spacer (ITS)-DNA and nadh1 mitochondrial gene were also amplified. DNA sequences of ITS and mt-DNA regions were deposited in GenBank (Nos. GU108602 and GU108603). Comparison of the sequences showed 100% homology with P. alni subsp. alni (GenBank Nos. FJ746679 and DQ202490). P. alni subsp. alni was recovered from trees at 3 of 20 riparian alder stands with symptoms. Pathogenicity of one representative isolate was confirmed by inoculating 10 3-year-old A. glutinosa seedlings grown in pots. One shallow cut was made into the bark at the collar level. A colonized agar plug, from the margin of an actively growing colony of P. alni subsp. alni, was inserted beneath the flap that was sealed with Parafilm. Five controls seedlings received only sterile CA agar plugs. Plants were incubated at 24°C and 95% humidity for 30 days. On inoculated plants, necroses progressed bidirectionally from the wound, and dead leaves and wilting of shoots were observed. P. alni subsp. alni was recovered from inoculated seedlings, but not from controls. To our knowledge, this is the first report of Phytophthora rot on alder caused by P. alni subsp. alni in Spain. References: (1) C. M. Brasier et al. Mycol. Res. 108:1172, 2004. (2) J. Gibbs et al. For. Comm. Bull. 126, 2003 (3) R. Ioos et al. Eur. J. Plant Pathol. 112:323, 2005. (4) T. Jung et al. Plant Pathol. 53:197, 2004.

[EN] An analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest transplants, larger specimen trees, landscape plants and ornamentals, plus 2525 areas in which trees and shrubs were planted, is presented based on work conducted by 38 research groups in 23 European countries between 1972 and 2013. Forty-nine Phytophthora taxa were recorded in 670 nurseries (91.5%); within these nurseries, 1614 of 1992 nursery stands (81.0%) were infested, although most affected plants appeared healthy. In forest and landscape plantings, 56 Phytophthora taxa were recovered from 1667 of 2525 tested sites (66.0%). Affected plants frequently showed symptoms such as crown thinning, chlorosis and dieback caused by extensive fine root losses and/or collar rot. Many well-known highly damaging host¿Phytophthora combinations were frequently detected but 297 and 407 new Phytophthora¿host associations were also observed in nurseries and plantings, respectively. On average, 1.3 Phytophthora species/taxa per infested nursery stand and planting site were isolated. At least 47 of the 68 Phytophthora species/taxa detected in nurseries and plantings were exotic species several of which are considered well established in both nurseries and plantings in Europe. Seven known Phytophthora species/taxa were found for the first time in Europe, while 10 taxa had not been previously recorded from nurseries or plantings; in addition, 5 taxa were first detections on woody plant species. Seven Phytophthora taxa were previously unknown to science. The reasons for these failures of plant biosecurity in Europe, implications for forest and semi-natural ecosystems and possible ways to improve biosecurity are discused., The authors are grateful to all public and private owners of nurseries and plantings who contributed to this extensive study. T. Jung acknowledges the support by the Regione Autonoma della Sardegna, Visiting Professor Program at the University of Sassari, Italy. The authors also thank the COST Office and the European Council for providing the European COST Actions FP0801 (http://www.cost.eu/domains_actions/fps/Actions/FP0801) and FP 1002 (http://www.cost.eu/domains_actions/fps/Actions/FP1002), the EU projects FOR-THREATS and ISEFOR, and BiodivERsA project RESIPATH as platforms for stimulating discussions on the nursery pathway and possible management solutions.

Phytophthora alni is the causal organism responsible for devastating losses occurring on riparian alders stands in Europe. This emergent hybrid pathogen has multiple variants that have been placed in three subspecies (1). P. alni subsp. uniformis and P. alni subsp. multiformis are reported to be less aggressive than P. alni subsp. alni, though all are considered pathogenic. In Spain, P. alni subsp. alni was detected for the first time in 2009 in Galicia (northwestern Spain) causing root and collar rot on riparian alder populations (3,4), but other subspecies had not been identified. In April 2011, a survey along the Deza River in Galicia was carried out to clarify the Phytophthora sp. associated with the alder decline. Thirty riparian Alnus glutinosa stands, from both sides of the river, were surveyed. Samples of bark and roots of 18 alder stands that showed symptoms of Phytophthora rot and soil from all 30 stands were collected. Roots and tissue from fresh, active, inner bark lesions from 54 trees were transferred to selective medium V8-PARPH agar and incubated for 7 days at 22°C in the dark. P. alni subsp. alni (1) was isolated from roots, bark, or soil in five alder stands. Another Phytophthora sp. was isolated from the bark of one symptomatic tree located in Silleda (Pontevedra), transferred to carrot agar (CA), and incubated in the dark. On CA, the isolate produced irregular and appressed colonies with an optimum growth temperature of 22 to 23°C. The isolate was homothallic with smooth-walled oogonia with a diameter ranging from 36 to 50 μm and two-celled, amphigynous antheridia (1). In soil extract, noncaducous, nonpapillate, ellipsoid-to-ovoid sporangia were produced. Average sporangium were 43.4 × 30.1 μm with a length/breadth ratio of 1.43. Internal proliferation occurred. Amplification of DNA was accomplished by sequence characterized amplified region (SCAR)-PCR primers (2). The amplicon sizes obtained were identical to P. alni subsp. uniformis. Internal transcribed spacer (ITS) (DC6-ITS6/ITS4) and nadh1 (NADHF1/NADHR1) mitochondrial gene regions were also amplified and deposited in GenBank (Nos. JN880411 and JN880410). Comparison of the sequences showed 100% homology with P. alni subsp. uniformis (GenBank Nos. GU259293 and DQ202489). Pathogenicity was tested on 10 3-year-old black alder plants grown in pots. A shallow wound was made with a scalpel at the root collar level of each plant. A 5-mm-diameter mycelia plug, taken from the margin of a 7-day-old culture grown on CA, was inserted in every wound and sealed with Parafilm. Five black alder control plants received only sterile CA agar plugs. Plants were kept at 24°C and 80% humidity. After 3 months, wilting of shoots, dead leaves, and dark stained necroses of the bark tissue varying in length from 0.8 to 5 cm were observed on inoculated plants. Control plants remained healthy. P. alni subsp. uniformis was recovered from inoculated plants, but not from controls. To our knowledge, this is the first time that P. alni subsp. uniformis has been reported in Spain. The presence of a new subspecies in a new region can result in hybridization between individuals of different species or subspecies. This process may allow the rapid evolution and adaptation of these species to new hosts or environmental conditions. References: (1) C. M. Brasier et al. Mycol. Res. 108:1172, 2004. (2) R. Ioos et al. Eur. J. Plant Pathol. 112:323, 2005. (3) C. Pintos et al. Plant Dis. 94:273, 2010. (4) A. Solla et al. Plant Pathol.59:78, 2010.