European And Mediterranean Plant Protection Organization Research Articles

Interface between pest risk science and policy: the EPPO perspective

The European and Mediterranean Plant Protection Organisation (EPPO) is an intergovernmental organization responsible for cooperation in plant protection in the European and Mediterranean region. It provides global distribution maps of pests, and intends to identify the areas at risk from new and emerging pests, in the framework of Pest Risk Analyses. EPPO has developed a decision-support scheme for Pest Risk Analysis (DSS) and a computer program (CAPRA) to assist pest risk analysts in running the decision-support scheme. Dedicated rating guidance and a Climatic Suitability Risk Mapping Decision-Support Scheme have recently been developed to guide assessors in identifying the potential area of establishment of a pest. All these tools have been developed taking into account both pest risk science available and needs of policy makers. The use of these tools and of mapping software are undertaken within the framework of EPPO Pest Risk Analyses, as illustrated through the examples of Thaumatotibia leucotreta (Lepidoptera) and Apriona germari (Coleoptera).

Eradication and control of invasive alien plants in the Mediterranean Basin: towards better coordination to enhance existing initiatives

The European and Mediterranean Plant Protection Organization (EPPO), in the framework of its activities in the Mediterranean Basin, launched a questionnaire to gather information on eradication actions and control actions for invasive alien plants. Thirty‐four (34) eradication actions were reported, 16 occurring in Spain, 7 in Italy, 7 in France, 1 in Portugal, 1 in Malta, and 2 on the southern rim of the Mediterranean, with 1 in Israel and 1 in Tunisia. Twenty‐two (22) species were targeted, and the habitats where such actions were undertaken most frequently were coastal dunes, sandy shores and aquatic ecosystems. Most of the species that have been the object of an eradication action were known invasive species recorded in the EPPO lists, such as Ailanthus altissima, Buddleia davidii, Carpobrotus spp., Eichhornia crassipes, Ludwigia peploides, Pennisetum setaceum, Pistia stratiotes, Solanum elaeagnifolium and Sicyos angulatus. Other eradicated species have a limited distribution in the EPPO region and may represent emerging invasive plants, such as Ambrosia confertifolia, Cylindropuntia rosea, Leersia oryzoides, Leptochloa fusca subsp. uninervia and Marsilea drummondii. Control actions concerning 90 species were also reported. A large number of eradication actions, as well as management actions, are therefore happening in Mediterranean countries. At present countries appear to operate with complete autonomy, without consulting neighbouring countries or other stakeholders within the country. There is therefore a need for coordination of new eradication actions.

Implementation of International Standards for Phytosanitary Measures no. 7 Phytosanitary Certification System and no. 12 Phytosanitary Certificates

The International Standards for Phytosanitary Measures No. 7 Phytosanitary Certification System and No. 12 Phytosanitary Certificates are crucial Standards for the functioning of a reliable and efficient exchange of information between National Plant Protection Organizations (NPPOs) on consignments moving in international trade. These two Standards were revised in 2011 and they may in some cases be implemented in different ways. The European and Mediterranean Plant Protection Organization (EPPO), in partnership with the Near East Plant Protection Organization (NEPPO), organized the Workshop ‘Toward a harmonized implementation of International Standards for Phytosanitary Measures no. 7 Phytosanitary Certification System and no. 12 Phytosanitary Certificates in Antalya (TR) from 20 to 22 November 2012 to share experiences and discuss practices on how these two standards are being implemented. Thirty‐six participants from 22 countries attended this workshop. Their discussions on the implementations of ISPM 7 and ISPM 12 concerned various aspects of the certification system and of the use of phytosanitary certificates, and are summarized here. Aspects of the certification system included staffing, information on importing countries’ phytosanitary requirements, models of phytosanitary certificates and record‐keeping; aspects of phytosanitary certificates included the purpose of the certificates, attachments, certified copies, alterations, replacements, issuance after dispatch, means of conveyance, description of the products, additional declarations (including standardized wording), how to deal with re‐export and transit situations, and the use of electronic certificates. The workshop concluded with recommendations and observations on the implementation of ISPM 7 and ISPM 12.

Outcome of the First Round of Public Consultation on the draft Guidance Document on the Risk Assessment of Plant Protection Products on Bees (Apis mellifera, Bombus spp. and Solitary Bees)

Outcome of the First Round of Public Consultation on the draft Guidance Document on the Risk Assessment of Plant Protection Products on Bees (Apis mellifera, Bombus spp. and Solitary Bees)

DNA barcoding of <I>Mycosphaerella</I> species of quarantine importance to Europe

The EU 7th Framework Program provided funds for Quarantine Barcoding of Life (QBOL) to develop a quick, reliable and accurate DNA barcode-based diagnostic tool for selected species on the European and Mediterranean Plant Protection Organization (EPPO) A1/A2 quarantine lists. Seven nuclear genomic loci were evaluated to determine those best suited for identifying species of Mycosphaerella and/or its associated anamorphs. These genes included β-tubulin (Btub), internal transcribed spacer regions of the nrDNA operon (ITS), 28S nrDNA (LSU), Actin (Act), Calmodulin (Cal), Translation elongation factor 1-alpha (EF-1α) and RNA polymerase II second largest subunit (RPB2). Loci were tested on their Kimura-2-parameter-based inter- and intraspecific variation, PCR amplification success rate and ability to distinguish between quarantine species and closely related taxa. Results showed that none of these loci was solely suited as a reliable barcoding locus for the tested fungi. A combination of a primary and secondary barcoding locus was found to compensate for individual weaknesses and provide reliable identification. A combination of ITS with either EF-1α or Btub was reliable as barcoding loci for EPPO A1/A2-listed Mycosphaerella species. Furthermore, Lecanosticta acicola was shown to represent a species complex, revealing two novel species described here, namely L. brevispora sp. nov. on Pinus sp. from Mexico and L. guatemalensis sp. nov. on Pinus oocarpa from Guatemala. Epitypes were also designated for L. acicola and L. longispora to resolve the genetic application of these names.

First Report of Xanthomonas arboricola pv. pruni in Ornamental Prunus laurocerasus in the Netherlands.

In 2008, Dutch ornamental plant growers observed a leaf spot of cherry laurel (Prunus laurocerasus) at a greater incidence (5 to 50%) than the usual sporadic level (<1%). For advice on disease control, ~5 to 10% of these growers contacted Dutch regulatory officials. In November and December 2008, six symptomatic samples from northern and southern parts of the Netherlands were submitted for diagnosis. Leaf spots were chlorotic, most had a necrotic brown center with a distinct margin, and the spots readily abscised, resulting in a "shot-hole" appearance. Leaf spots from the samples were surface sterilized (2 s in 70% vol/vol alcohol), blotted dry on tissue paper, chopped into pieces (1 to 2 mm in diameter), and incubated for 30 min in 10 mM phosphate-buffered saline (PBS) (1). A 20-μl aliquot of extract per sample was streaked by dilution plating on four plates of yeast peptone glucose agar medium (1), and the plates were incubated for 2 to 3 days at 28°C. Isolations from all six samples yielded Xanthomonas-like colonies. After purification, characterization of all six isolates revealed oxidative, nonfermentative metabolism of glucose by rod-shaped, gram-negative bacterial cells. All six isolates were identified as Xanthomonas arboricola pv. pruni based on biochemical tests (1), fatty acid analysis (4), and immunofluorescence (IF) using polyclonal antibodies (Plant Research International, the Netherlands). Pathogenicity was tested on potted peach plants (cvs. Peregrine and Vaes Oogst) and on detached leaves of P. laurocerasus (cv. Novita) (1). The six field isolates from 2008 were each inoculated (108 CFU/ml) onto four leaves per plant of each of two peach plants (replicates). As positive control treatments, two reference strains (ATCC 19312 and PD740) were each inoculated onto the same number of leaves and plants, and as a noninoculated negative control treatment, leaves of two peach plants were treated with sterile 10 mM PBS buffer (1). All leaves inoculated with the six field isolates and the two reference strains developed typical bacterial spot symptoms in 3 to 4 weeks. Negative control plants showed no symptoms. The detached leaf assay performed with the same treatments on each of two leaves (replicates) showed identical results. The bacterium was reisolated from leaf spots associated with each of the eight symptomatic treatments and identity of the reisolates was confirmed by IF. Additionally, genotypic variation of 35 Dutch isolates of X. arboricola pv. pruni was assessed by BOX-PCR assay with the BOX A1R primer set (3), and Gyrase B gene sequencing (2). Both methods revealed 100% homology among the 35 isolates, suggesting a single, recent introduction of X. arboricola pv. pruni into the Netherlands. In a 2009 survey to assess distribution of the disease in the Netherlands, X. arboricola pv. pruni was found in 41 fields. Infected hosts included P. laurocerasus cvs. Otto Luyken, Rotundifolia, Novita, Etna, Anbri, Herbergii, Mischeana, and Caucasia. X. arboricola pv. pruni is a quarantine organism in countries affiliated under the EPPO (European and Mediterranean Plant Protection Organization). Phytosanitary measures were taken to prevent movement of infested plants from nurseries where X. arboricola pv. pruni was detected.

Tools for visualizing and integrating pest risk assessment ratings and uncertainties*

The application of pest risk analysis (PRA) decision‐support schemes, such as that used by the European and Mediterranean Plant Protection Organization (EPPO), generates many ratings for likelihood or magnitude of risk factors, each with an associated uncertainty. In accordance with the international standard ISPM 11 (FAO, 2004), questions have been devised to assess the key elements of pest risk in the four main sections of pest risk assessment: Entry, Establishment, Spread and Impact. After completing each section, risk assessors are required to give a summary rating and an uncertainty score for that section. The large number of question ratings and uncertainty scores make the task of summarizing each section and its uncertainty quite difficult. Two graphical tools have been developed to aid this task: the PRA Risk score and uncertainty visualizer (Visualizer) and the Rule‐based matrix model (RBMM). The Visualizer presents a case summary graph on a single page in such a way that the risk assessors and peer reviewers can see rating scores and uncertainties in a pictorial manner; the RBMM integrates all the individual questions in the assessment through a hierarchy of rules that attempt to mimic the logic used by the assessors and are arranged in the form of a flow chart to give an overall rating with an accompanying expression of uncertainty.

First Report of Little Cherry Disease from Sweet Cherry (Prunus avium) and Sour Cherry (P. cerasus) in the Czech Republic.

Little cherry disease (LChD), a virus disease of sweet (Prunus avium) and sour cherries (P. cerasus), is caused by members of the Closteroviridae family. Symptoms are especially visible on fruits and leaves. Leaves become red or bronze in late summer and fall. Fruit are small, angular, and pointed. Fruits are unmarketable due to a characteristic bitter flavor. LChD also causes reduction of yield (1). Sweet and sour cherries are the second (after apples) most often grown fruit species in the Czech Republic. Since LChD occurred in Germany (1) and Poland (2) in 2007 and 2008, sweet and sour cherry trees with LChD symptoms were surveyed in orchards in the East Bohemia Region of the Czech Republic. The presence of LChD was determined by reverse transcription (RT)-PCR and woody indicator plants, as recommended by the European and Mediterranean Plant Protection Organization (EPPO). Different parts of plants were taken from trees with suspicious symptoms to observe the dynamics of virus infection during the 2009 growing season. Total RNA was isolated from young leaves, blossoms, fruits, and fully developed leaves with a CONCERT Plant RNA Purification Reagent (Invitrogen, Carlsbad, CA) (3). RT-PCR was performed with a QIAGEN OneStep RT-PCR Kit (Qiagen, Hilden, Germany) and oligonucleotides previously described (4). Oligonucleotide LCV3EC (5'-GCTCTAGAGGCACCTTTTATTTTTTATATATGC-3'), complementary to position 16910 to 16934 (GenBankAccession No. Y10237) (with the addition of eight nonviral nucleotides to introduce an XbaI site), was used as a negative-sense primer in RT reactions and PCR. Oligonucleotide LCV16659 (5'-GTTATAGAATTCACTGCAAGTG-3') was used as a positive-sense primer for PCR amplification. The program used for cDNA synthesis was 50°C for 30 min, followed by denaturation for 10 min at 95°C, 35 cycles of 45 s at 94°C, 45 s at 58°C, and 45 s at 72°C. A final incubation was at 72°C for 5 min (1). The finished PCR products (430 bp) were analyzed on 1% agarose gels (stained with SYBR green). According to the preliminary results, young leaves from buds (67% of samples of selected trees with LChD were positive), blossoms (67% positive), and leaves taken in autumn (67% positive) were optimal for the detection of LChD by RT-PCR. The trial with woody indicator plant species was established in the field. Indicators P. avium cv. Sam and P. avium cvs. Bing, F12/1, and Canindex (4) were inoculated with buds from LChD-infected trees and observed for 2 years. Woody indicators remained symptomless throughout the first year of observation, but the indicators showed red coloration of leaves in late summer of the second year. P. avium cv. Canindex seems to be the best woody indicator for testing of LChD in the climatic conditions of the Czech Republic. To our knowledge, this is the first report of LChD in the Czech Republic.

First Report of a Brugmansia sp. Infected by Tomato apical stunt viroid in Belgium.

During a routine screening of ornamentals by the Federal Agency for the Safety of the Food Chain (FASFC) in Belgium, a pospiviroid was detected in a symptomless Brugmansia sp. (angel's trumpets) coming from the Netherlands. Detection was performed on a leaf sample by reverse transcription (RT)-PCR, first using universal pospiviroid primer pair (2) VIR1/VIR2 and subsequently with semispecific primer pair (3) CEVd-FW/RE, to amplify the whole viroid genome. Amplicons of expected sizes (260 and 360 bp, respectively) were detected and the sequencing of the CEVd-FW/RE amplicon (GenBank Accession No. FN994891) revealed that the viroid from a Brugmansia sp. was a Tomato apical stunt viroid (TASVd) showing 99.7% similarity with the Sj1 isolate found in Solanum jasminoides (GenBank Accession No. AM777161). Diluted-sap inoculation attempts on tomato from lyophilized material were unsuccessful in agreement with previous results obtained with a Brugmansia isolate of Potato spindle tuber viroid (4). TASVd is mentioned on the alert list of EPPO (European and Mediterranean Plant Protection Organization) because of the heavy yield losses it can induce in tomato, its asymptomatic presence on different ornamental plants (S. jasminoides, Lycianthes rantonnetii, and Streptosolen jamesonii), and its capacity to be transmitted by contact to different Solanaceae as well as by bumble bees to tomato (1). The contaminated plants found in the survey by FASFC have been destroyed to avoid accidental transmission to potato and tomato. To our knowledge, this is the first report of TASVd in a Brugmansia sp.

Larval performances and life cycle completion of the Siberian moth, Dendrolimus sibiricus (Lepidoptera: Lasiocampidae), on potential host plants in Europe: a laboratory study on potted trees

The Siberian moth, Dendrolimus sibiricus, Tschtv. is the most harmful defoliator of coniferous forests in North Asia. The pest has already spread over the Urals and continues moving westwards. Recently, it has been recommended for quarantine in member countries by European and Mediterranean Plant Protection Organization (EPPO). The performances of the pest on coniferous species planted in Europe were assessed on a range of potted trees corresponding to the spectrum of economically important conifers in the EU: European larch Larix decidua, Norway spruce Picea abies, Scots pine Pinus sylvestris, European black pine Pinus nigra, and the North American species: Douglas fir Pseudotsuga menziesii and grand fir Abies grandis. Larvae showed a potential to survive and complete the development on all these host tree species. Favorable hosts were grand fir, European larch, and Douglas fir that allowed higher survival, better larval development, and as a result, yielded heavier pupae and adult moths with higher longevity. Black pine was a poor host but, however, could still support larval and pupal development. Norway spruce and Scots pine had an intermediate behavior. If accidentally introduced to Europe, the Siberian moth may become especially damaging in forest stands predominated by European larch and by the North American firs. Norway spruce and especially the two-needle pines will be less prone to intensive defoliation by this species. The fact that the pest may damage the range of economically important coniferous species should be taken into account in the pest risk assessment for Europe and also for North America where the Siberian moth occurrence is considered likely.

Nipping aquatic plant invasions in the bud: weed risk assessment and the trade

The importation and sale of ornamental pond and aquarium plants is the most important pathway for the introduction of potential aquatic weeds into and subsequent spread of these within a country. Most current aquatic weeds were at one time deliberately imported for ornamental use. This article discusses a weed risk assessment approach to evaluating new potential weeds. It assesses the potential invasiveness of an aquatic plant based on its habitat versatility, competitive ability, reproductive output and dispersal mechanisms, range of potential impacts, potential distribution and resistance to management activities. The Aquatic Weed Risk Assessment Model (AWRAM) has been used to evaluate potential aquatic weeds in New Zealand, Australia and the USA. A similar approach could be used to guide the management of aquatic weeds in Europe. Banning the importation of highly ranked species effectively keeps biosecurity risks off-shore. Assessment of aquatic plant trade patterns, especially volumes of high-risk species, along with knowledge of current and potential distribution of those species and ease of management, are all factors to be considered when evaluating candidate plants for prevention of sale and distribution. This is a highly effective way of restricting both long-distance dispersal and density of propagules. A cooperative approach involving researchers, policy and trade representatives has been an effective way to achieve regulation of this risk pathway. European initiatives to prevent the distribution of potential aquatic weeds include the preparation of lists of known invasive aquatic species by the European and Mediterranean Plant Protection Organization (EPPO), with recommendations to member countries to consider measures to prevent their spread (e.g. banning importation of, banning sale and distribution of, and undertaking control programmes against those species). Belgian initiatives include an upcoming Royal Decree concerning the importation, exportation and possession of non-native invasive species, development of codes of conduct with the horticultural sector and prohibiting the sale, purchase and intentional release of these species in the wild. This article reviews these approaches and discusses other species of concern.

Invasive alien plants in plant health: a review of the past ten years

The International Plant Protection Convention (IPPC) provides the background for National Plant Protection Organisations (NPPOs) to regulate and control invasive alien species that are harmful to plants. This subject was specifically discussed for the first time 10 years ago at IPPC level, and further explored by an IPPC open‐ended working group. The resulting concept was considered at EU level, and the EU Council supported the suitability of the plant health framework for these species, requesting the EU Commission to further analyse the needs for regulatory work in the EU plant health regime. Subsequently the European and Mediterranean Plant Protection Organization (EPPO) started a new working programme. The international conference ‘Invasive alien species and the IPPC’ set a signal for IPPC contracting parties to encourage their NPPOs to enforce actions on invasive alien species. IPPC standards on pest risk analysis (PRA) were adapted so as to include invasive alien species harmful to plants, and a memorandum of cooperation was adopted between the Secretariats of the IPPC and the Convention on Biological Diversity (CBD). At present, the EU Commission, DG Environment is developing a European strategy on invasive alien species. The EU Plant Health Regulatory System is currently subjected to a major evaluation process in which a clearer inclusion of invasive alien species into the system is one of the strategic discussions.

Enhancements of pest risk analysis techniques

International, regional and national standards for plant health pest risk assessment and examples of their use from countries around the globe were examined together with similar documents from related fields such as animal health, nature conservation and genetically modified organism (GMO) assessment to determine how the consistency of assessing risk, or components of risk, within and between assessments is addressed. A range of approaches was identified that could be adopted and adapted for use in a revised decision support scheme for quarantine pests by the European and Mediterranean Plant Protection Organization (EPPO) to aid consistency. No single scheme contained a mechanism to ensure or guarantee consistency and no single scheme contained all of the approaches identified to maximize consistency. If the approach of using a five division scale to describe individual components that contribute to evaluating the overall pest risk is to be maintained in the EPPO scheme, then the primary needs required in the EPPO scheme to enhance consistency are (i) the provision of examples that describe divisions within the scales, or alternative but equivalent descriptors that allow assessors to distinguish between divisions, and (ii) a mechanism to combine risk elements in a consistent and transparent way. Features that would help inexperienced assessors include a clear structure, clear rating guidance, questions posed unambiguously, provision of standardized answers and an easily applicable method to interpret and summarize risk ratings. Beyond improvements to the EPPO scheme, assessors using the scheme will need training. Providing links to information and suggesting data sources that would help assessors answer questions would also be helpful (this is being addressed in Work Package 1 of PRATIQUE).

First report of the quarantine pathogen Xanthomonas arboricola pv. pruni on apricot and plum in Switzerland

Xanthomonas arboricola pv. pruni (Xap), cause of stone fruit bacterial spot on many Prunus species, is a European and Mediterranean Plant Protection Organisation (EPPO) A2-list quarantine pathogen (Anonymous, 2006). It can cause significant yield loss and tree death. In Europe, Xap occurs in France, Italy, Bulgaria, Romania and Ukraine, but appears to be spreading due to changes in trade patterns, climate, host range and/or pathogen genotype. This is the first report of the bacterial pathogen in Switzerland, occurring with very limited distribution. Xap was first detected on apricot trees and fruit (Prunus armeniaca) showing symptoms in 2005 in four orchards located in canton Valais, the primary Swiss production region. It was detected in 2009 on Japanese apricot (P. mume) inter-cropped with apricot in two of these orchards. Isolation from symptom-bearing fruit, leaf and canker samples using YCDA medium confirmed recovered colonies to be Xap based on colony morphology, quinate metabolism, serology (Neogen Europe, EXPRESS™), gyrB sequencing (Parkinson et al., 2009; GenBank Accession No. FJ719771–FJ719773) and pathogenicity bioassays with detached peach leaves. Direct detection in symptom-bearing fruit, leaves and cankers was achieved in 100% of samples using Xap-specific PCR primers (Pagani, 2004) and in 40% using X. fragariae/arboricola primers (Weller et al., 2007). These primer sets gave 100 and 93% agreement, respectively, with standard identification methods when applied to Xap isolates. All Swiss isolates were copper sensitive. During intensive surveys between 2006 and 2009 throughout the region where the bacterium was first detected (208 ha), no incidence of disease has been observed outside the four original infected orchards. In three of these orchards Xap is considered eradicated, with all symptom-bearing trees removed in the fourth. This suggests probable introduction via planting material rather than fruit or aerosols. Xap is considered present with limited distribution but not eradicated. This work was funded by the Swiss Secretariat for Education and Research within COST Action 873.

Detection of pathogenic Verticillium spp. using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Verticillium spp. have been listed by the European and Mediterranean Plant Protection Organization (EPPO) and China as plant quarantine pests. Although attempts have been made to develop a simple routine laboratory assay to detect these organisms, none are routinely used. We describe for the first time a robust assay for reliable identification of Verticillium spp. using protein fingerprinting data obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS). Several sample preparation methods and matrices were investigated to improve mass spectra for the routine identification of six species of Verticillium spp.(Verticillium dahiliae, V. alboatrum, V. fungicola, V. nigrescens, and V. lecanii) by MALDI-TOF-MS. Using the optimized experimental method, we constructed a protein fingerprint database for six species of Verticillium and established a analysis criteria of log(Score). This MALDI-TOF-MS protocol should prove useful as a rapid and reliable assay for distinguishing different Verticillium spp.

Review of carrot fly control in Northern Europe – 20091

In February 2009, the European and Mediterranean Plant Protection Organization (EPPO) held a workshop to discuss the management of carrot fly (Psila rosae) within Europe. Prior to the workshop, participants completed a questionnaire about carrot fly and current control methods and some of the information is summarised in this paper. In general, this pest is controlled adequately at present, but there is a heavy reliance on insecticides. The responses to the questionnaire highlighted a number of issues, in particular: the limited range and efficacy of the insecticides available at present, concerns about the availability of effective control measures in the future and a need for improvements in the targeting of treatments through forecasting and monitoring and the use of treatment thresholds.

Design and development of a DNA microarray for rapid identification of multiple European quarantine phytopathogenic bacteria

The European and Mediterranean Plant Protection Organization (EPPO) lists for quarantine status 26 phytopathogenic bacteria which pose serious economic threats to agricultural and natural ecosystems. A prototype diagnostic DNA microarray was developed for the rapid and simple identification of 22 of these quarantine bacteria. The microarray has 38 probes targeted to the 16S rDNA and the house-keeping genes rpoB, groEL and ftsZ. The 16S rDNA probes were selected according to a multiple-probe concept taking into account the hierarchical structure of phytobacterial systematics. Hybridisation with Cy3-labelled PCR products of corresponding genes enabled differentiation of the quarantine bacteria down to the species and subspecies level.

PRATIQUE: a research project to enhance pest risk analysis techniques in the European Union

PRATIQUE is an EC‐funded 7th Framework research project designed to address the major challenges for pest risk analysis (PRA) in Europe. It has three principal objectives: (a) to assemble the datasets required to construct PRAs valid for the whole of the EU, (b) to conduct multi‐disciplinary research that enhances the techniques used in PRA and (c) to provide a decision support scheme for PRA that is efficient and user‐friendly. The research will be undertaken by scientists from 13 institutes in the EU and one each from Australia and New Zealand with subcontractors from institutes in China and Russia. They will produce a structured inventory of PRA datasets for the EU and undertake targeted research to improve existing procedures and develop new methods for (a) the assessment of economic, environmental and social impacts, (b) summarising risk while taking account of uncertainty, (c) mapping endangered areas (d) pathway risk analysis and systems approaches and (e) guiding actions during emergencies caused by outbreaks of harmful organisms. The results will be tested and provided as protocols, decision support systems and computer programs with examples of best practice linked to a computerised European and Mediterranean Plant Protection Organization (EPPO) PRA scheme.

Heat Treatment Effects on Strawberry Plant Survival and Angular Leaf Spot, Caused by Xanthomonas fragariae, in Nursery Production.

Angular leaf spot is an important disease in strawberry nursery production. The European and Mediterranean Plant Protection Organization (EPPO) lists Xanthomonas fragariae as an A2 quarantine pathogen. Therefore, nurseries wishing to export plants to European countries must maintain phytosanitary standards to exclude X. fragariae. To help nurseries achieve these standards, heat treatment for killing or reducing the number of viable bacterial cells in strawberry crown tissue was investigated. First, the sensitivity of bacteria to heat was determined by dispensing 1-ml aliquots of standardized cell suspensions in microcentrifuge tubes for each of four isolates of X. fragariae, including the type culture, and submerging the tubes in water at 36, 40, 44, 48, 52, and 56°C for 0, 1, 2.5, 5, 10, 15, 30, 60, 120, 240, 360, and 480 min. Bacteria were transferred to growth medium to determine the proportion surviving heat treatment. Two trials were conducted in a greenhouse to determine the sensitivity of bare-root plants to heat treatment. In the first trial, plants of cvs. Camarosa and Diamante from two different nurseries were heat treated as follows: (i) plants placed in metallic mesh cages and immersed directly into water (industry standard, direct dip); (ii) plants sealed in a plastic bag and the bag immersed in water (bagged dry); or (iii) plants wetted in warm water, sealed in a plastic bag, and then immersed in water (bagged wet). Plants were treated at 44 or 48°C for 0, 60, 120, 180, and 240 min. In the second trial, plants of cvs. Camarosa, Camino Real, Diamante, Oso Grande, Strawberry Festival, and Ventana from a single nursery were subjected to the same treatments. In both trials, plants were potted after treatment and rated for growth characteristics. Results showed that populations of bacteria exposed to 56 and 52°C were killed completely after 15 and 60 min of exposure, respectively; both treatments killed plants. Bacterial populations exposed to 44°C for 4 h or 48°C for 2 h were reduced by 105 or 106 CFU/ml. The same treatments minimally affected vegetative growth of plants bagged dry or wet, but flowering was adversely affected. These heat treatments were selected for testing of nursery stock of several cultivars in field trials established at two locations in successive years. The survival rate among cultivars was similar to that observed in greenhouse trials, and angular leaf spot developed appreciably only in non-heat-treated control plots. Heat treatment of strawberry nursery stock is feasible and can be used to supplement standard production practices for producing pathogen-free nursery stock.

Development of National Reference Laboratories in the European Union1

Since 2004 discussions on the need for greater international co‐operation and coordination between diagnostic laboratories have taken place at several meetings of the EU Heads of National Plant Protection Organisations (NPPOs) and of the European and Mediterranean Plant Protection Organization (EPPO). Technical discussions on criteria for, and tasks and responsibilities of, National Reference Laboratories (NRLs) took place in a Commission Expert Working Group in September 2007. The meeting was attended by representatives from 13 Member States. The experts discussed the issues broadly and very actively and it was possible to elaborate an agreed Guidance Paper containing the main elements for the establishment of NRLs, including a priority list of individual pests for which such laboratories are needed. At their meeting in December 2007, the EU Heads of the NPPOs supported the establishment of NRLs as far as possible and where necessary. It was agreed that the Guidance Paper is a suitable common basis for the establishment of NRLs in the Member States and that it should be reviewed on the basis of the experience gained at national level.