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Vein clearing of zucchini (VCZ) is a disease caused by seedborne bacteria that affects young plants of Cucurbita pepo subsp. pepo. VCZ agents are distributed into four phylogenetic clusters within clades 2a and 2ba of phylogroup 2 of the Pseudomonas syringae species complex. All these strains are pathogenic to squash, but only certain strains can also attack melon and cucumber. Strains belonging to clades 2b and 2d are sometimes isolated from zucchini seeds but have not been associated with VCZ epidemics. Identification tools for VCZ agents are required to improve disease control. Primers were designed to implement a seven-gene multilocus sequence analysis (MLSA) scheme for a collection of 60 strains isolated from zucchini seeds. The MLSA showed a clear predominance of strains of cluster 2ba-A and the presence of VCZ strains in a fifth cluster (2ba-C). PCR tests were designed to characterize strains in the VCZ clusters, and a multiplex qPCR test was proposed to distinguish strains with a cucurbit host range extended to melon and cucumber, harboring hopZ5 and sylC, from other strains harboring avrRpt2 and sylC. Additional qPCR tests were also designed to gain insights into clade-2b and -2d strains that can be isolated from cucurbits. These tools evaluated in silico with the NCBI database and experimentally with a collection of 112 strains detected all target strains, except for the test dedicated to clade-2b strains, and excluded 96.7 to 100% of nontarget strains. These tools are intended to serve phylogenetic studies, epidemiological monitoring, and seed testing. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Abstract Background Bacteria of the genus Xanthomonas cause economically significant diseases in various crops. Their virulence is dependent on the translocation of type III effectors (T3Es) into plant cells by the type III secretion system (T3SS), a process regulated by the master response regulator HrpG. Although HrpG has been studied for over two decades, its regulon across diverse Xanthomonas species, particularly beyond type III secretion, remains understudied. Results In this study, we conducted transcriptome sequencing to explore the HrpG regulons of 17 Xanthomonas strains, encompassing six species and nine pathovars, each exhibiting distinct host and tissue specificities. We employed constitutive expression of plasmid-borne hrpG*, which encodes a constitutively active form of HrpG, to induce the regulon. Our findings reveal substantial inter- and intra-specific diversity in the HrpG* regulons across the strains. Besides 21 genes directly involved in the biosynthesis of the T3SS, the core HrpG* regulon is limited to only five additional genes encoding the transcriptional activator HrpX, the two T3E proteins XopR and XopL, a major facility superfamily (MFS) transporter, and the phosphatase PhoC. Interestingly, genes involved in chemotaxis and genes encoding enzymes with carbohydrate-active and proteolytic activities are variably regulated by HrpG*. Conclusions The diversity in the HrpG* regulon suggests that HrpG-dependent virulence in Xanthomonas might be achieved through several distinct strain-specific strategies, potentially reflecting adaptation to diverse ecological niches. These findings enhance our understanding of the complex role of HrpG in regulating various virulence and adaptive pathways, extending beyond T3Es and the T3SS.

Xanthomonas hortorum pv. carotae is a pathogen responsible for the bacterial blight of carrot. Although it infects carrot fields worldwide, its diversity remains unknown. Here, we validated by PCR the identification as X. hortorum pv. carotae of most of the strains isolated from symptomatic carrots. We studied their diversity by sequencing seven housekeeping genes. The analysis confirmed the identity of most of the strains previously identified as X. hortorum pv. carotae and highlighted the presence of two clusters inside the pathovar carotae. The 18 non-X. hortorum pv. carotae have been identified as Xanthomonas from other species. As the X. hortorum pv. carotae strains clustered only in two groups by this analysis, a new multilocus variable number of tandem repeats analysis scheme was developed. It allowed us to validate the subclustering in two groups and observe diversity among them. At the same time, based on this study and data from the literature, we proposed the strain CFBP 7900 as the neopathotype strain of the pathovar. The strain should replace the holopathotype strain CFBP 4997, as it is no longer available in international collections. [Figure: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

ABSTRACTThe classical lineage of Mycobacterium ulcerans is the most prevalent clonal group associated with Buruli ulcer in humans. Its reservoir is strongly associated with the environment. We analyzed together 1,045 isolates collected from 13 countries on two continents to define the evolutionary history and population dynamics of this lineage. We confirm that this lineage spread over 7,000 years from Australia to Africa with the emergence of outbreaks in distinct waves in the 18th and 19th centuries. In sharp contrast with its global spread over the last century, transmission chains are now mostly local, with little or no dissemination between endemic areas. This study provides new insights into the phylogeography and population dynamics of M. ulcerans, highlighting the importance of comparative genomic analyses to improve our understanding of pathogen transmission.IMPORTANCEMycobacterium ulcerans is an environmental mycobacterial pathogen that can cause Buruli ulcer, a severe cutaneous infection, mostly spread in Africa and Australia. We conducted a large genomic study of M. ulcerans, combining genomic and evolutionary approaches to decipher its evolutionary history and pattern of spread at different geographic scales. At the scale of villages in an endemic area of Benin, the circulating genotypes have been introduced in recent decades and are not randomly distributed along the river. On a global scale, M. ulcerans has been spreading for much longer, resulting in distinct and compartmentalized endemic foci across Africa and Australia.

Xylella fastidiosa is a quarantine priority pest in Europe and several other countries as it represents a major threat to many cultivated and wild plants. Early detection of the pathogen is needed to reduce potential losses and to stop the bacterial dissemination. Very few molecular methods are available for rapid field detection to identify the pathogen. Here, we evaluated a new rapid commercial detection test called AmplifyRP, based on molecular recombinase polymerase amplification (RPA). The AmplifyRP test was compared with the quantitative PCR (qPCR) Harper's assay, which represents the standard method used in most laboratories all over the world. Specificity was tested in vitro on a panel of target and nontarget strains. Additionally, the sensitivity of the RPA test was tested on X. fastidiosa genomic DNA, and the selectivity was compared between different host plant matrices spiked with X. fastidiosa cell suspensions. Although the qPCR assay showed a higher sensitivity than the RPA test, the latter appeared to be a very specific, rapid, and portable technique for which no skills are required to proceed. These findings should enable growers and inspectors to choose an appropriate diagnostic method. [Figure: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

A genomic investigation into strains of the plant pathogen, Xylella fastidiosa, in France indicate an American origin with two waves of invasion.

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Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by plants of Prunus domestica grafted on Prunus cerasifera imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. One quarantine pest (Lopholeucaspis japonica), two protected zone quarantine pests (Erwinia amylovora and Xanthomonas arboricola pv. pruni) and one non‐regulated pest (Eotetranychus prunicola) that fulfilled all relevant criteria were selected for further evaluation. For these four pests, the risk mitigation measures proposed in the technical dossier from Ukraine were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Xanthomonas arboricola pv. pruni being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,870 and 10,000 bundles (consisting of 10 plants each) per 10,000 would be free from Xanthomonas arboricola pv. pruni.

Abstract Background Common bacterial blight (CBB) caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans is one of the major threats to common bean crops (Phaseolus vulgaris L.). Resistance to CBB is particularly complex as 26 quantitative resistance loci to CBB have been described so far. To date, transcriptomic studies after CBB infection have been very scarce and the molecular mechanisms underlying susceptibility or resistance are largely unknown. Results We sequenced and annotated the genomes of two common bean genotypes being either resistant (BAT93) or susceptible (JaloEEP558) to CBB. Reciprocal BLASTp analysis led to a list of 20,787 homologs between these genotypes and the common bean reference genome (G19833), which provides a solid dataset for further comparative analyses. RNA-Seq after inoculation with X. phaseoli pv. phaseoli showed that the susceptible genotype initiated a more intense and diverse biological response than the resistant genotype. Resistance was linked to upregulation of the salicylic acid pathway and downregulation of photosynthesis and sugar metabolism, while susceptibility was linked to downregulation of resistance genes and upregulation of the ethylene pathway and of genes involved in cell wall modification. Conclusions This study helps better understanding the mechanisms occurring during the early colonization phase of common bean by Xanthomonas and unveils new actors potentially important for resistance and susceptibility to CBB. We discuss the potential link between the pathways induced during bean colonization and genes induced by transcription activator-like effectors (TALEs), as illustrated in other Xanthomonas pathovars.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’). This Scientific Opinion covers plant health risks posed by 1‐ to 3‐year‐old dormant grafted plants and rootstocks of Malus domestica imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests associated with the commodity were evaluated against specific criteria for their relevance for this opinion. Two quarantine pests (Lopholeucaspis japonica and Tobacco ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and one non‐regulated pest (Eotetranychus prunicola) that fulfilled all relevant criteria were selected for further evaluation. For Erwinia amylovora, for which special requirements are specified in Commission Implementing Regulation (EU) 2019/2072, Annex X, item 9, the fulfilment of these requirements was evaluated. Based on the information provided in the dossier, the specific requirements for Erwinia amylovora were not met. For the three remaining selected pests, the risk mitigation measures proposed in the technical dossier from Ukraine were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Eotetranychus prunicola being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated with 95% certainty that between 9,912 and 10,000 bundles (consisting of 50 plants each) per 10,000 would be free from Eotetranychus prunicola.

Abstract The EFSA Plant Health Panel performed a pest categorisation of Colletotrichum fructicola Prihast., a well‐defined polyphagous fungus of the C. gloeosporioides complex which has been reported from all the five continents to cause anthracnose, bitter rot and leaf spotting diseases on over 90 cultivated and non‐cultivated woody or herbaceous plant species. The pathogen is not included in EU Commission Implementing Regulation 2019/2072. Because of the very wide host range, this pest categorisation focused on Camellia sinensis, Citrus sinensis, C. reticulata, Fragaria × ananassa, Malus domestica, M. pumila, Persea americana, Prunus persica, Pyrus pyrifolia and P. bretschneideri for which there was robust evidence that C. fructicola was formally identified by morphology and multilocus gene sequencing analysis. Host plants for planting and fresh fruits are the main pathways for the entry of the pathogen into the EU. There are no reports of interceptions of C. fructicola in the EU. The pathogen has been reported from Italy and France. The host availability and climate suitability factors occurring in some parts of the EU are favourable for the establishment of the pathogen. Economic impact on the production of the main hosts is expected if establishment occurs. Phytosanitary measures are available to prevent the re‐introduction of the pathogen into the EU. Although the pathogen is present in the EU, there is a high uncertainty on its actual distribution in the territory because of the re‐evaluation of Colletotrichum taxonomy and the lack of systematic surveys. Therefore, the Panel cannot conclude with certainty on whether C. fructicola satisfies the criterium of being present but not widely distributed in the EU to be regarded as a potential Union quarantine pest unless systematic surveys for C. fructicola are conducted and Colletotrichum isolates from the EU in culture collections are re‐evaluated.

Abstract Background The phytopathogenic bacterium Xylella fastidiosa was thought to be restricted to the Americas where it infects and kills numerous hosts. Its detection worldwide has been blooming since 2013 in Europe and Asia. Genetically diverse, this species is divided into six subspecies but genetic traits governing this classification are poorly understood. Results SkIf (Specific k-mers Identification) was designed and exploited for comparative genomics on a dataset of 46 X. fastidiosa genomes, including seven newly sequenced individuals. It was helpful to quickly check the synonymy between strains from different collections. SkIf identified specific SNPs within 16S rRNA sequences that can be employed for predicting the distribution of Xylella through data mining. Applied to inter- and intra-subspecies analyses, it identified specific k-mers in genes affiliated to differential gene ontologies. Chemotaxis-related genes more prevalently possess specific k-mers in genomes from subspecies fastidiosa, morus and sandyi taken as a whole group. In the subspecies pauca increased abundance of specific k-mers was found in genes associated with the bacterial cell wall/envelope/plasma membrane. Most often, the k-mer specificity occurred in core genes with non-synonymous SNPs in their sequences in genomes of the other subspecies, suggesting putative impact in the protein functions. The presence of two integrative and conjugative elements (ICEs) was identified, one chromosomic and an entire plasmid in a single strain of X. fastidiosa subsp. pauca. Finally, a revised taxonomy of X. fastidiosa into three major clades defined by the subspecies pauca (clade I), multiplex (clade II) and the combination of fastidiosa, morus and sandyi (clade III) was strongly supported by k-mers specifically associated with these subspecies. Conclusions SkIf is a robust and rapid software, freely available, that can be dedicated to the comparison of sequence datasets and is applicable to any field of research. Applied to X. fastidiosa, an emerging pathogen in Europe, it provided an important resource to mine for identifying genetic markers of subspecies to optimize the strategies attempted to limit the pathogen dissemination in novel areas.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers the plant health risks posed by 2‐year‐old grafted bare rooted plants for planting of Juglans regia imported from Turkey, taking into account the available scientific information, including the technical information provided by Turkey. The relevance of any pest for this Opinion was based on evidence following defined criteria. Two EU quarantine pests, Anoplophora chinensis and Lopholeucaspis japonica, and three pests not regulated in the EU, two insects (Garella musculana, Euzophera semifuneralis) and one fungus (Lasiodiplodia pseudotheobromae), fulfilled all relevant criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Turkey were evaluated by considering the possible limiting factors. For these pests, an expert judgement was given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pests, including uncertainties associated with the assessment. While the estimated degree of pest freedom varied among pests, Lasiodiplodia pseudotheobromae was the pest most frequently expected on the commodity. The expert knowledge elicitation indicated, with 95% certainty, that 9,554 or more grafted bare rooted plants per 10,000 will be free from Lasiodiplodia pseudotheobromae.

Abstract The European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of Elasmopalpus lignosellus (Zeller) (Leipidoptera: Pyralidae) for the territory of the EU following interceptions of the organism within the EU and its addition to the EPPO Alert List. E. lignosellus feeds on over 70 species; hosts include cereals, especially maize, legumes, brassicas and a range of grasses. Seedlings of ornamental and forest trees can also be hosts. E. lignosellus is established in tropical and subtropical areas of North, Central and South America. Eggs are usually laid in the soil or on the lower stem of hosts. Larvae develop in the soil and feed on roots and stems causing stunting and yield losses. Plants for planting, rooted with growing media, or with stems cut close to the soil, and fresh vegetables harvested with stems, such as asparagus and cabbage, provide pathways for entry. Population development is favoured by dry and hot conditions (27–33°C). Adults fly and can be carried in air currents. Adults are recorded from temperate areas within the Americas contributing some uncertainty regarding the limits of its establishment potential in the EU. Although cultivated and wild hosts are distributed across the EU, impacts are likely to be confined to production areas on sandy soils around the coastal Mediterranean during hot dry years. Phytosanitary measures are available to inhibit the entry of E. lignosellus. E. lignosellus satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the citrus pulp borer, Citripestis sagittiferella (Lepidoptera: Pyralidae), for the EU. This oligophagous species, which feeds on Citrus spp., occurs in Southeast Asia, mostly in lowlands but can also be found up to 1,200 m above sea level. Adults oviposit on citrus fruit at any stage of the fruit development. Larvae feed in the fruit then abandon it to pupate in the soil within an earthen cocoon. C. sagittiferella is multivoltine in its native range. This species is not included in EU Commission Implementing Regulation 2019/2072. Potential entry pathways for C. sagittiferella, such as Citrus spp. plants for planting with foliage and soil/growing medium, and soil/growing medium by themselves can be considered as closed. The citrus fruit pathway remains open for countries where C. sagittiferella is known to occur. Indeed, this species was intercepted several times in the UK during the last decade. Hosts of C. sagittiferella are available (Citrus spp.) in the southern EU. The EU has climatic conditions that are also found in countries where C. sagittiferella occurs although it is unknown whether C. sagittiferella occurs in those areas. Economic impact in citrus production is anticipated if establishment and spread occur. C. sagittiferella satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest. There is uncertainty about the climatic requirements of this species, which may hamper its establishment in the EU.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the navel orangeworm, Amyelois transitella (Lepidoptera: Pyralidae), for the EU. This polyphagous species feeds on citrus, almonds, pistachios, grapes and other crops cultivated in the EU. A. transitella occurs in North, Central and South America in a range of climates some of which also occur in the EU. Adult females lay up to 200 eggs on overripe, damaged, cracked or mummified fruits or nuts. In citrus, eggs are laid at the navel end of damaged fruit. On occasions, they may be found on adjacent leaves or stems. This species is not included in EU Commission Implementing Regulation 2019/2072. Potential entry pathways for A. transitella, such as plants for planting, and fruit, exist. The pest is not known to be present in the EU territory although it has been intercepted in Italy and Austria. Should A. transitella arrive in the EU the availability of hosts and occurrence of potentially suitable climates would be conducive for establishment. Should this species establish in the EU, yield and quality losses in citrus, nuts, stone and pome fruit production is anticipated. A. transitella satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Xanthomonas campestris pv. campestris (Xcc) causes the black rot of cruciferous plants. This seed-borne bacterium is considered as the most destructive disease to cruciferous crops. Although sources of contamination are various, seeds are the main source of transmission. Typical symptoms of black rot were first observed in 2011 on cabbage and cauliflower fields in the main production areas of Algeria. Leaf samples displaying typical symptoms were collected during 2011 to 2014, and 170 strains were isolated from 45 commercial fields. Xcc isolates were very homogeneous in morphological, physiological and biochemical characteristics similar to reference strains, and gave positive pathogenicity and molecular test results (multiplex PCR with specific primers). This is the first record of Xcc in Algeria. Genetic diversity within the isolates was assessed in comparison with strains isolated elsewhere. A multilocus sequence analysis based on two housekeeping genes (gyrB and rpoD) was carried out on 77 strains representative isolates. The isolates grouped into 20 haplotypes defined with 68 polymorphic sites. The phylogenetic tree obtained showed that Xcc is in two groups, and all Algerian strains clustered in group 1 in three subgroups. No relationships were detected between haplotypes and the origins of the seed lots, the varieties of host cabbage, the years of isolation and agroclimatic regions.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation EU/2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by bare rooted and potted plants of Nerium oleander that are imported from Turkey, taking into account the available scientific information, including the technical information provided by the Turkish NPPO. The relevance of any pest for this opinion was based on evidence following defined criteria. One species, the EU non‐regulated pest Phenacoccus solenopsis, fulfilled all relevant criteria and was selected for further evaluation. For this pest, the risk mitigation measures proposed in the technical dossier from Turkey were evaluated taking into account the possible limiting factors. For this pest, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,719 and 10,000 plants per 10,000 would be free of P. solenopsis.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers the plant health risks posed by the two following hazelnut commodities to be imported from Serbia. 1. Bare rooted plants: 1‐ to 3‐year‐old plants of Corylus avellana or C. avellana grafted on C. colurna, without leaves. 2. Plants in pots: 2‐year‐old plants of C. avellana, without leaves. The assessment was performed by taking into account the available scientific information, including the technical information provided by Serbia. The relevance of any pest for this Opinion was based on evidence following defined criteria. One EU quarantine pest, i.e. Flavescence dorée phytoplasma, fulfilled all relevant criteria and was selected for further evaluation. For this pathogen, the risk mitigation measures proposed in the Technical Dossier from Serbia were evaluated separately for bare rooted plants and for plants in pots, taking into account the possible limiting factors. For the selected pathogen, an expert judgement was given on the likelihood of pest freedom of plants for planting, for both commodities taken together, considering the risk mitigation measures, including uncertainties associated with the assessment. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,837 and 10,000 bare rooted plants and plants in pots per 10,000 would be free of Flavescence dorée phytoplasma.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation EU/2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by bare rooted and potted plants of Robinia pseudoacacia that are imported from Turkey, taking into account the available scientific information, including the technical information provided by the Turkish NPPO. The relevance of any pest for this opinion was based on evidence following defined criteria. Three species, the EU‐quarantine pests Anoplophora chinensis and Lopholeucapsis japonica, and the EU non‐regulated pest Pochazia shantungensis fulfilled all relevant criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Turkey were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The estimated degree of pest freedom varies among the pests evaluated, with L. japonica being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,521 and 10,000 plants per 10,000 would be free of L. japonica.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Taking into account the available scientific information, including the technical information provided by the applicant country, this Scientific Opinion covers the plant health risks posed by the following commodities: dormant, free of leaves, bare‐rooted grafted plants and rootstocks of Juglans regia imported from Moldova. A list of pests potentially associated with the commodities was compiled. The relevance of any pest was assessed based on evidence following defined criteria. The EU‐quarantine pest Xiphinema rivesi non‐EU populations fulfilled these criteria and hence was selected for further evaluation. For this pest, the risk mitigation measures described in the technical dossier from Moldova were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom for this pest taking into consideration the risk mitigation measures, including uncertainties associated with the assessment. The Expert Knowledge Elicitation indicated, with 95% certainty, that 9,959 or more bare‐rooted plants per 10,000 will be free from X. rivesi.

Abstract Following a request from the European Commission, the EFSA Panel on Plant Health examined evidence as to whether the import of fruits of Musa (bananas and plantains) could provide a pathway into the EU for Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) or other non‐EU Tephritidae for which Musa is a host. Relevant scientific and technical information, including unpublished information provided to the EFSA Panel on Plant Health by the European Commission from research conducted in Cabo Verde, were taken into account. The majority of EU imports of Musa fruit comes from Ecuador, Colombia and Costa Rica where B. dorsalis does not occur. Commercial Musa fruits are harvested at ‘green stage one’ before they begin to ripen naturally. Postharvest processes are designed to ensure that only high quality, unripe fruit are exported. Green stage one fruit are transported to the EU in controlled conditions and stimulated to ripen when exposed to exogenous ethylene in ripening rooms in the EU. There is no evidence that any Tephritidae can naturally infest commercial varieties of Musa fruit at green stage one or earlier. When experimentally infested with eggs of Tephritidae, larvae fail to develop in green stage one fruit. Physical and chemical changes that occur during fruit ripening enable B. dorsalis and 11 other species of Tephritidae to oviposit and develop in Musa at later stages of fruit development. Reports of B. dorsalis or other Tephritidae infesting bunches of Musa fruit are a consequence of the fruit being left to develop beyond green stage one in the field. There is no evidence that commercially grown fruits of Musa, for export to the EU, provide a pathway for the entry of non‐EU Tephritidae. Passengers bringing Musa fruit from countries where Tephritidae can infest ripened Musa fruit do however provide a potential pathway for the entry of non‐EU Tephritidae into the EU territory.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects. This Scientific Opinion covers plant health risks posed by tubers of Ullucus tuberosus imported from Peru, taking into account the available scientific information, including the technical information provided by Peru. The relevance of an EU quarantine pest for this opinion was based on evidence that: (i) the pest is present in Peru, (ii) U. tuberosus is a host of the pest and (iii) the pest can be associated with the commodity. The relevance of any other pest, not regulated in the EU, was based on evidence that: (i) the pest is present in Peru (ii) the pest is absent in the EU; (iii) U. tuberosus is a host of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose a potential risk for the EU territory. There are five pests i.e. one insect (Amathynetoides nitidiventris), two nematodes (Atalodera andina and Nacobbus aberrans) and two viruses (the Andean potato latent virus (APLV) and the potato virus T (PVT)) that fulfilled all relevant criteria were selected for further evaluation. For the five pests, the risk mitigation measures proposed in the technical dossier from Peru were evaluated taking into account the possible limiting factors. For each of the five pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with PVT being the pest most frequently expected on the imported commodities. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,157 and 10,000 tubers out of 10,000 would be free of PVT.

Abstract The European Commission requested EFSA Panel on Plant Health to evaluate a dossier from Israel in which the application of the systems approach to mitigate the risk of entry of Thaumatotibia leucotreta to the EU when trading citrus fruits is described. After collecting additional evidence from the Plant Protection and Inspection Services (PPIS) of Israel, and reviewing the published literature, the Panel performed an assessment on the likelihood of pest freedom for T. leucotreta on citrus fruits at the point of entry in the EU considering the Israelian systems approach. An expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures on T. leucotreta, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,863 and 10,000 citrus fruits per 10,000 will be free from this pest. The Panel also evaluated each risk mitigation measure in the systems approach and identified any weaknesses associated with them. Specific actions are identified that could increase the efficacy of the systems approach.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Momordica fruits originating from countries where Thrips palmi is known to occur qualify as high risk plants. This Scientific Opinion covers the introduction risk for T. palmi posed by fruits of Momordica charantia L. imported from Honduras, taking into account the available scientific information, including the technical information provided by the National Service of Agrifood Health and Safety (SENASA) of Honduras. The risk mitigation measures proposed in the technical dossier from Honduras were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom taking into consideration the potential pest pressure in the field, the risk mitigation measures acting on the pest in the field and in the packinghouse, including uncertainties associated with the assessment. For T. palmi on M. charantia fruits from Honduras, an expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures acting on T. palmi, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,406 and 10,000 M. charantia fruits per 10,000 will be free from T. palmi.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Momordica fruits originating from countries where Thrips palmi is known to occur qualify as high risk plants. This Scientific Opinion covers the introduction risk for T. palmi posed by fruits of Momordica charantia L. imported from Mexico, taking into account the available scientific information, including the technical information provided by the National Service of Health, Safety and Agrifood Quality (Senasica) of Mexico. The risk mitigation measures proposed in the technical dossier from Mexico were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom taking into consideration the potential pest pressure in the field, the risk mitigation measures acting on the pest in the field and in the packinghouse, including uncertainties associated with the assessment. For T. palmi on M. charantia fruits from Mexico, an expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures acting on T. palmi, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,492 and 10,000 M. charantia fruits per 10,000 will be free from T. palmi.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Momordica fruits originating from countries where Thrips palmi is known to occur qualify as high‐risk plants. This Scientific Opinion covers the introduction risk for T. palmi posed by fruits of Momordica charantia L. imported from Thailand, taking into account the available scientific information, including the technical information provided by the Department of Agriculture of Thailand. The risk mitigation measures proposed in the technical dossier from Thailand were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom taking into consideration the potential pest pressure in the field, the risk mitigation measures acting on the pest in the field and in the packing house, including uncertainties associated with the assessment. For T. palmi on M. charantia fruits from Thailand, an expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures acting on T. palmi, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,496 and 10,000 M. charantia fruits/10,000 will be free from T. palmi.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Momordica fruits originating from countries where Thrips palmi is known to occur qualify as high‐risk plants. This Scientific Opinion covers the introduction risk for T. palmi posed by fruits of Momordica charantia L. imported from Sri Lanka, taking into account the available scientific information, including the technical information provided by the National Plant Quarantine Service of Sri Lanka. The risk mitigation measures proposed in the technical dossier from Sri Lanka were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom taking into consideration the potential pest pressure in the field, the risk mitigation measures acting on the pest in the field and in the packing house, including uncertainties associated with the assessment. For T. palmi on M. charantia fruits from Sri Lanka, an expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures acting on T. palmi, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9831 and 10,000 M. charantia fruits/10,000 will be free from T. palmi.

Abstract The EFSA Panel on Plant health was requested to prepare and deliver risk assessments for commodities listed in the relevant Implementing Acts as ‘High risk plants, plant products and other objects’ (Commission Implementing Regulation (EU) 2018/2019 establishing a provisional list of high risk plants, plant products or other objects, within the meaning of Article 42 of Regulation (EU) 2016/2031). This scientific opinion covers the plant health risks posed by the following commodities: (i) scions and (ii) grafted plants of Persea americana imported from Israel, taking into account the available scientific information, including the technical information provided by the Plant Protection and Inspection Services from Israel. The relevance of an EU quarantine pest for this opinion was based on evidence that: (i) the pest is present in Israel; (ii) P. americana is a host of the pest and (iii) the pest can be associated with the commodity. The relevance of any other pest, not regulated in the EU, was based on evidence that: (i) the pest is present in Israel; (ii) the pest is absent in the EU; (iii) P. americana is a host of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose a potential risk for the EU territory. Twenty‐six pests (15 insects, one mite, 9 fungi and one viroid) that fulfilled all criteria were selected for further evaluation. For the 26 selected pests, the risk mitigation measures proposed in the technical dossier were evaluated. Limiting factors on the effectiveness of the measures were documented. For each of the 26 pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including any uncertainties. The fungi Lasiodiplodia pseudotheobromae and Neoscytalidium dimidiatum were the pests most frequently expected on the imported commodities. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,573 and 10,000 bundles of scions per 10,000; and 9,747 and 10,000 grafted plants per 10,000 would be free of these two fungi.

Xylella fastidiosa (Xf) is a phytopathogenic bacterium with a repertoire of self-replicating genetic elements, including plasmids, pathogenicity islands, and prophages. These elements provide potential avenues for horizontal gene transfer both within and between species and have the ability to confer new virulence traits, including the ability to colonize new host plants. However, they can also serve as a ‘footprint’ to type plasmid-bearing strains. Genome sequencing of several strains of Xf subsp. fastidiosa sequence type (ST) 1 from Mallorca Island, Spain, revealed the presence of a 38 kb plasmid (pXFAS_5235). In this study, we developed a PCR-based typing approach using primers targeting the traC gene to determine the presence of pXFAS_5235 plasmid or other plasmids carrying this gene in a world-wide collection of 65 strains X. fastidiosa from different subspecies and STs or in 226 plant samples naturally infected by the bacterium obtained from the different outbreaks of Xf in Spain. The traC gene was amplified only in the plant samples obtained from Mallorca Island infected by Xf subsp. fastidiosa ST1 and from all Spanish strains belonging to this ST. Maximum-likelihood phylogenetic tree of traC revealed a close relatedness among Spanish and Californian strains carrying similar plasmids. Our results confirm previous studies, which suggested that a single introduction event of Xf subsp. fastidiosa ST1 occurred in the Balearic Islands. Further studies on the presence and role of plasmids in Xf strains belonging to the same or different subspecies and STs can provide important information in studies of epidemiology, ecology, and evolution of this plant pathogen.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers the plant health risks posed by the following commodities: i) dormant and free of leaves 1‐year‐old bare rooted plants and ii) free of leaves 1‐year‐old liners of Ficus carica imported from Israel, taking into account the available scientific information, including the technical information provided by Israel. The relevance of any pest for this opinion was based on evidence following defined criteria. Four EU quarantine pests, Euwallacea fornicatus, Hypothenemus leprieuri, Scirtothrips dorsalis and Spodoptera frugiperda, and 11 EU non‐regulated pests fulfilled all relevant criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Israel were evaluated separately for bare rooted plants and for liners, taking into account the possible limiting factors. For these pests, an expert judgement was given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The estimated degree of pest freedom varied among the pests evaluated. Aonidiella orientalis and Russellaspis pustulans were the most frequently expected pests on the imported bare rooted plants, and Scirtothrips dorsalis on liners. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,585 and 10,000 bare rooted plants per 10,000 would be free of Aonidiella orientalis and Russellaspis pustulans and between 9,456 and 10,000 liners per 10,000 would be free of Scirtothrips dorsalis.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Diaphorina citri (Hemiptera: Liviidae) (Asian citrus psyllid) for the EU. D. citri is a key pest of citrus in several countries as it is a vector of serious bacterial pathogens, the putative causal agents of Huanglongbing (HLB) also known as citrus greening. Eggs are laid on tips of growing shoots on and between unfurling leaves. Females may lay more than 800 eggs during their lives. Nymphs pass through five instars. The life cycle requires from 14 to 49 days, depending upon the season. There is no diapause, but populations are low in winter. It overwinters as an adult which may live for several months. The species completes 9–10 generations/year; however, under protected conditions, up to 16 generations have been recorded. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates D. citri, as a quarantine pest not known to occur in the EU territory. Fruits and plants for planting provide potential pathways for entry into the EU. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. The introduction of D. citri would have an economic impact in the EU through direct but mainly indirect effects due to potential transmission of HLB. Phytosanitary measures are available to reduce the likelihood of entry. D. citri satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. D. citri does not meet the criteria of occurring in the EU, nor plants for planting being the principal means of spread, for it to be regarded as a potential Union regulated non‐quarantine pest.

Abstract Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest categorisation of four phytoplasmas of tuber‐forming Solanum spp. known to occur only outside the EU or having a limited presence in the EU. The only tuber‐forming species of Solanum reported to be phytoplasma infected is S. tuberosum. This opinion covers ‘Candidatus Phytoplasma americanum’, ‘Ca. P. aurantifolia’‐related strains (GD32; St_JO_10, 14, 17; PPT‐SA; Rus‐343F; PPT‐GTO29, ‐GTO30, ‐SINTV; Potato Huayao Survey 2; Potato hair sprouts), ‘Ca. P. fragariae’‐related strains (YN‐169, YN‐10G) and ‘Ca. P. pruni’‐related strains (Clover yellow edge; Potato purple top AKpot7, MT117, AKpot6; PPT‐COAHP, ‐GTOP). Phytoplasmas can be detected by molecular methods and are efficiently transmitted by vegetative propagation. Phytoplasmas are also transmitted in a persistent and propagative manner by some insects belonging to families within Cicadomorpha, Fulgoromorpha and Sternorrhyncha (order Hemiptera). No transovarial, pollen or seed transmission has been reported. The reported natural host range of the phytoplasmas categorised here varies from restricted (‘Ca. P. americanum’, and ‘Ca. P. fragariae’‐related strains) to wide (‘Ca. P. aurantifolia’‐related strains and ‘Ca. P. pruni’‐related strains), thus increasing the possible entry pathways in the latter case. S. tuberosum is widely cultivated in the EU. All the categorised phytoplasmas can enter and spread through the trade of host plants for planting, and by vectors. Establishment of these phytoplasmas is not expected to be limited by EU environmental conditions. The introduction of these phytoplasmas in the EU would have an economic impact. There are measures to reduce the risk of entry, establishment, spread and impact. Uncertainties result from limited information on distribution, biology and epidemiology. All the phytoplasmas categorised here meet the criteria evaluated by EFSA to qualify as potential Union quarantine pests, and they do not meet all the criteria to qualify as potential regulated non‐quarantine pests, because they do not occur or are not known to be widespread in the EU.

Abstract Following a request from the EU Commission, the Panel on Plant Health performed a categorisation of beet necrotic yellow vein virus (BNYVV), the causal agent of the sugar beet rhizomania disease. The virus is currently listed in Annex III as a protected zone (PZ) quarantine pest of the Commission Implementing Regulation (EU) 2019/2072. The identity of the BNYVV is well established. BNYVV is a soil‐borne virus transmitted by the obligate root plasmodiophorid endoparasite Polymyxa betae. BNYVV is widely distributed in the EU, but is not reported in the following EU PZs: Ireland, France (Brittany), Portugal (Azores), Finland and Northern Ireland. The virus may enter, become established and spread in the PZs via P. betae resting spores with soil and growing media as such or attached to machinery and with roots and tubercles of species other than B. vulgaris and with plants for planting. Introduction of BNYVV would have a negative impact on sugar beet and other beet crops in PZs, because of yield and sugar content reduction. Phytosanitary measures are available to reduce the likelihood of entry and spread in the PZs. Once the virus and its plasmodiophorid vector have entered a PZ, their eradication would be difficult due to the persistence of viruliferous resting spores in the soil. The main knowledge gaps or uncertainties identified concerning the presence of BNYVV in the PZs and the incidence and distribution of BNYVV in Switzerland, a country to which a range of specific requirements do not apply. BNYVV meets all the criteria that are within the remit of EFSA to qualify as a potential protected zone union quarantine pest. Plants for planting are not considered as a main means of spread, and therefore BNYVV does not satisfy all the criteria evaluated by EFSA to qualify as potential Union regulated non‐quarantine pest.

Abstract Following a request from the European Commission, the EFSA Panel on Plant Health prepared a list of non‐EU phytoplasmas of tuber‐forming Solanum spp. A systematic literature review and search of databases identified 12 phytoplasmas infecting S. tuberosum. These phytoplasmas were assigned to three categories. The first group (a) consists of seven non‐EU phytoplasmas, known to occur only outside the EU (‘Candidatus Phytoplasma americanum’, ‘Ca. P. australiense’, ‘Ca. P. fragariae’‐related strain (YN‐169, YN‐10G) and ‘Ca. P. hispanicum’) or having only limited presence in the EU (‘Ca. P. aurantifolia’–related strains, ‘Ca. P. pruni’‐related strains and ‘Ca. P. trifolii’). The second group (b) consists of three phytoplasmas originally described or reported from the EU. The third group (c) consists of two phytoplasmas with substantial presence in the EU, whose presence in S. tuberosum is not fully supported by the available literature. Phytoplasmas of categories (b) and (c) were excluded at this stage from further categorisation efforts. Three phytoplasmas from category (a) (‘Ca. P. australiense’, ‘Ca. P. hispanicum’ and ‘Ca. P. trifolii’) were excluded from further categorisation, as a pest categorisation has already been performed by EFSA. Comments provided by the EU Member States were integrated in the opinion. The main uncertainties of this listing concern: the taxonomy, the geographic distribution and prevalence and host range. The following phytoplasmas considered as non‐EU and whose presence in S. tuberosum is fully supported by literature (category (a)) are categorised by the Panel in a separate opinion: ‘Ca. P. americanum’, ‘Ca. P. fragariae’‐related strain (YN‐169, YN‐10G), ‘Ca. P. aurantifolia’–related strains and ‘Ca. P. pruni’‐related strains.

Abstract The European Commission submitted to the EFSA Panel on Plant Health a Dossier by USDA proposing a systems approach to mitigate the risk of entry of Bretziella fagacearum to the EU when trading oak logs with bark from the USA. Due to the forthcoming ban of methyl bromide (MB), the Dossier indicates sulfuryl fluoride (SF) as the substitute fumigant for this commodity. After collecting additional evidence from USDA,EU NPPOs, external experts and the published literature, the Panel performed a quantitative assessment on the likelihood of pest freedom for B. fagacearum at the point of entry in the EU, comparing the proposed systems approach with those already implemented by Commission Decision 2005/359/EC. The Panel provided also a non‐quantitative assessment for all risk reduction options (RROs) proposed to be undertaken in the EU, from the point of entry to processing at the sawmill. The quantitative assessment until the EU point of entry, based on experts’ judgement, indicated that: i) the most effective import option remains the current one with MB (95% certainty that between 9,573 and 10,000 containers per 10,000 would be free of B. fagacearum), followed by that with SF (95% certainty that between 8,639 and 10,000 containers per 10,000 would be free of B. fagacearum) and, last, by the other existing option based on delivering white oak logs in certain periods of the year to certain regions of the EU without fumigation (95% certainty, between 7,803 and 10,000 containers per 10,000). RROs proposed to be undertaken in the EU are expected to further reduce the risk of establishment of B. fagacearum, should these RROs be regulated, correctly implemented and checked by NPPOs. A wood pathway analysis is needed to quantitatively assess the importance of each measure and to optimise regulatory actions and risk management efforts.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae) for the EU. This subspecies occurs in North and Central America. Adults oviposit on annual plants in the families Asteraceae, Chenopodiaceae, Cucurbitaceae, Fabaceae, Poaceae, Polygonaceae and Solanaceae. Adults feed on tender plant parts in hosts in 40 additional botanical families. Preimaginal development takes place on the roots of the host plant, where larvae feed and pupate. D. undecimpunctata howardi is a multivoltine species. Overwintering adults, which may enter a facultative diapause, abandon crops in autumn and reinvade them in spring. D. undecimpunctata howardi is not known to occur in the EU and is regulated in Annex IIA of Commission Implementing Regulation 2019/2072. This species is a competent vector of Erwinia tracheiphila (Smith) Bergey et al., which can cause bacterial wilt, a serious disease of cucurbits. The bacterium, which is restricted to temperate midwestern and eastern North America, is not regulated in the EU. Within Commission Implementing Regulation 2019/2072, potential entry pathways for D. undecimpunctata howardi, such as Asteraceae, Poaceae and Solanaceae plants for planting with foliage and soil/growing medium, and soil/growing media by themselves can be considered as closed. However, plants for planting of the families Chenopodiaceae, Cucurbitaceae, Fabaceae and Polygonaceae are not specifically regulated. Should D. undecimpunctata howardi arrive in the EU, climatic conditions and availability of susceptible hosts provide conditions suitable for establishment and further spread. Economic impact is anticipated in maize and outdoor cucurbit production. D. undecimpunctata howardi satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest. This species does not meet the criteria of being present in the EU, nor plants for planting being the main pathway for spread, for it to be regarded as a potential regulated non‐quarantine pest.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) for the EU. L. decemlineata is primarily known as a major defoliator of potatoes (Solanum tuberosum); feeding damage can result in significant yield loss. Field grown tomatoes and eggplants can be attacked and wild solanaceous species are also hosts. Having first established in Europe from North America in the early 20th century, L. decemlineata is now distributed in 21 EU Member States and is regulated in the EU by Commission Implementing Regulation 2019/2072, (Annex III) with protected zones in place for Cyprus, Ireland, Malta, Northern Ireland, parts of Spain (Ibiza and Menorca) and Portugal (Azores and Madeira), seven districts of Finland and five counties in Sweden. Adults occasionally enter some protected zones due to wind currents that carry flying adults; pathways are also provided by plant produce moved in trade. The availability of hosts and suitable climate make establishment of the pest possible in protected zones in the EU, especially in the southern EU. Spread within the protected zones could occur via adult flight and via leafy vegetables moved in trade. Impacts on potato yields would be expected within the protected zones; outdoor grown tomatoes and eggplants could be impacted in the protected zones of southern Member States too. Previous incursions into the current protected zones have been eradicated. L. decemlineata satisfies all of the criteria that are within the remit of EFSA to assess, to conclude that it is a potential protected zone quarantine pest. L. decemlineata does not satisfy all of the criteria that are within the remit of EFSA to assess with respect to regulated non‐quarantine pest status, specifically plants for planting are not the main means of spread.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the beetle Diabrotica undecimpunctata undecimpunctata (Coleoptera: Chrysomelidae) for the EU. This species occurs in western USA and Mexico. Adults oviposit on annual plants in the families Chenopodiaceae, Cucurbitaceae, Fabaceae, Poaceae, Polygonaceae and Solanaceae. Adults feed on tender plant parts in hosts in 30 additional botanical families. Preimaginal development takes place on the roots of the host plant, where larvae feed and pupate. The insect completes one to three generations per year depending on temperature. Overwintering adults (no diapause) may abandon crops to seek shelter in wild vegetation and reinvade crops in spring. D. undecimpunctata undecimpunctata is not known to occur in the EU and is regulated in Annex IIA of Commission Implementing Regulation 2019/2072. This species is a competent vector of squash mosaic virus, a pathogen already present and not regulated in the EU. Within Commission Implementing Regulation 2019/2072, potential entry pathways for D. undecimpunctata undecimpunctata, such as Poaceae and Solanaceae plants for planting with foliage and soil/growing medium, and soil/growing media by themselves can be considered as closed. However, plants for planting of the families Chenopodiaceae, Cucurbitaceae, Fabaceae and Polygonaceae are not specifically regulated. Should D. undecimpunctata undecimpunctata arrive in the EU, climatic conditions and availability of susceptible hosts provide conditions suitable for establishment and further spread. Economic impact is anticipated. D. undecimpunctata undecimpunctata satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest. This species does not meet the criteria of being present in the EU nor plants for planting being the main pathway for spread for it to be regarded as a potential regulated non‐quarantine pest.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation EU/2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers all plant health risks posed by unrooted cuttings of Jasminum polyanthum produced in a protected environment (greenhouse) that are imported from Israel, taking into account the available scientific information, including the technical information provided by the NPPO of Israel by 15 March 2020. The relevance of an EU quarantine pest for this opinion was based on evidence that: (i) the pest is present in Israel; (ii) Jasminum is a host of the pest; and (iii) the pest can be associated with the commodity. The relevance of any other pest, not regulated in the EU, was based on evidence that: (i) the pest is present in Israel; (ii) the pest is absent in the EU; (iii) Jasminum is a host of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose a potential risk for the EU territory. Six species, the EU‐quarantine pest Scirtothrips dorsalis, and the EU non‐regulated pests Aonidiella orientalis,Milviscutulus mangiferae,Paracoccus marginatus,Pulvinaria psidii and Colletotrichum siamense fulfilled all relevant criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Israel were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The estimated degree of pest freedom varies among the pests evaluated, with S. dorsalis being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,958 and 10,000 bags per 10,000 would be free of S. dorsalis.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the planthopper Haplaxius crudus (Hemiptera: Cixiidae) for the EU. This species occurs from south‐eastern USA to Northern Brazil and on many Caribbean islands. Adults oviposit on grasses, mostly Poaceae and Cyperaceae in the vicinity of palms (Arecaceae). The pest can also be found on plants of the families Arecaceae, Heliconiaceae, Pandanaceae and Verbenaceae. Preimaginal development takes place on the roots of grasses, where nymphs feed. Upon emergence, adults move to palms for feeding and return to grasses for oviposition. H. crudus is regulated in Annex IIA of Commission Implementing Regulation 2019/2072 as Myndus crudus, a junior synonym. This species is a competent vector of Candidatus Phytoplasma palmae, the causal agent of coconut lethal yellowing, a disease also regulated in Annex IIA of the same regulation. Within this regulation, potential entry pathways for H. crudus, such as Arecaceae and Poaceae plants for planting with foliage and soil/growing medium, and soil/growing media by themselves can be considered as closed. However, plants for planting of the families Cyperaceae, Heliconiaceae, Pandanaceae and Verbenaceae are not specifically regulated. Should H. crudus arrive in the EU, climatic conditions and availability of susceptible hosts in a small area in southern EU (e.g. eastern Cyprus and south‐western Spain) may provide conditions for limited establishment, and further spread to neighbouring areas in the Mediterranean basin during summer months. Economic impact is anticipated only if Candidatus Phytoplasma palmae is also introduced into the EU. Phytosanitary measures are available to reduce the likelihood of entry. H. crudus satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest. This species does not meet the criteria of being present in the EU and plants for planting being the main pathway for spread for it to be regarded as a potential non‐quarantine pest.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Helicoverpa zea (Lepidoptera: Noctuidae) (American cotton bollworm, corn earworm) for the EU. H. zea is a polyphagous species that feeds on over 100 plant species. The crops most frequently recorded as host plants are maize, sorghum, cotton, beans, peas, chickpeas, tomatoes, aubergines, peppers and, to a lesser extent, clover, okra, cabbages, lettuces, strawberries, tobacco, sunflowers, cucurbits and ornamentals. H. zea preferentially feeds on flowers and fruits of the host. Eggs are laid mostly on maize silks. Larvae feed on the silks and kernels. Pupation takes place in the soil. Hibernation and estivation as pupa are reported. Adults are nocturnal. H. zea is a strong flier, able to fly up to 400 km during migration. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates H. zea. Fruits and plants for planting, with and without soil, provide potential pathways for entry into the EU. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. The introduction of H. zea could have an economic impact in the EU through qualitative and quantitative effects on agricultural production (e.g. tomatoes, soybean, sweet corn). Phytosanitary measures are available to reduce the likelihood of entry. H. zea satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. H. zea does not meet the criteria of (a) occurring in the EU, and (b) plants for planting being the principal means of spread for it to satisfy the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union regulated non‐quarantine pest.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of the species within the Andean Potato Weevil (APW) complex (Coleoptera: Curculionidae) for the EU. The complex consists of 14 species, 12 belong to the genus Premnotrypes, plus Phyrdenus muriceus and Rhigopsidius tucumanus. These weevils co‐occur in the Andean region, usually above 2,100 m. Eggs are deposited in plant debris close to potato plants. Upon hatching larvae immediately bore into potato tubers where they complete development. Except for R. tucumanus, which pupates inside the tuber, mature larvae leave the tuber and pupate in the soil. Adults can survive feeding on different plants but cannot deposit fertile eggs unless fed on potato foliage. P. muriceus can also complete development feeding on tomato and eggplant roots and occurs at lower altitudes from southern USA to central Argentina. Within the APW complex only species in the genus Premnotrypes are regulated in Annex IIA of Commission Implementing Regulation 2019/2072 as Premnotrypes spp. (non‐EU). Within this regulation potential pathways, such as solanaceous plants for planting with foliage and growing medium, seed and ware potatoes, and soil, can be considered as closed. There are no records of interception of any of these weevils in EUROPHYT. Should these species be introduced into the EU, climatic conditions and wide availability of potato crops in the EU territory would provide conditions for establishment, spread and economic impact. Phytosanitary measures are available to reduce the likelihood of entry. The species within the APW complex satisfy with no uncertainties the criteria that are within the remit of EFSA to assess, for them to be regarded as potential Union quarantine pests. Although human‐assisted movement of seed potatoes is considered the main mechanism for spread of these species, these weevils do not meet the criterion of occurring in the EU for them to be regarded as potential Union regulated non‐quarantine pests.

Abstract Following a request from the European Commission, the Panel on Plant Health performed a pest categorisation on tomato leaf curl New Delhi virus (ToLCNDV). ToLCNDV is a well‐defined bipartite Begomovirus species, sometimes associated with satellite molecules. It is transmitted by Bemisia tabaci to a wide range of hosts. ToLCNDV is reported from Estonia, Greece, Italy, Portugal and Spain, with limited distribution. The prevalent strain (ToLCNDV‐ES) in these countries is particularly adapted to cucurbits and is different from isolates reported outside the EU, which are better adapted to solanaceous crops and could therefore pose additional risk for EU agriculture. The virus is regulated under Commission Implementing Regulation (EU) 2019/2072. The main pathway of entry identified is plants for planting of susceptible hosts, even if entry could also occur via commodities carrying viruliferous B. tabaci and possibly by seeds. While establishment and local spread rely on B. tabaci, the virus can also be dispersed over long distances by movement of infected plants for planting. Establishment and spread are limited to regions with ecoclimatic conditions suitable for the establishment of vector populations (southern regions of Europe) or can occur as outbreaks wherever crops are grown under protected cultivation. The main uncertainties associated with this pest categorisation are the distribution and prevalence of ToLCNDV in the EU, the magnitude of the virus impact particularly on hosts different from Cucurbitaceae, and seed transmission. ToLCNDV meets all the criteria evaluated by EFSA to qualify as potential Union Quarantine Pest (QP); conversely, ToLCNDV does not meet the criterion of being widespread in the EU to qualify as a Regulated Non‐Quarantine Pest (RNQP). Should new data show that ToLCNDV is widespread in the EU, the possibility would exist for non‐EU isolates to qualify as QP, while ToLCNDV EU isolates (ToLCNDV‐ES) could qualify as RNQP.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Ripersiella hibisci (Hemiptera: Rhizoecidae) for the EU. R. hibisci occurs in Japan, China and Taiwan and has spread to the USA: Florida, Hawaii and the territory of Puerto Rico. R. hibisci is a polyphagous mealybug recorded feeding on roots of monocotyledonous and dicotyledonous plants. Root damage reduces nutrient and water uptake, retards plant growth and may cause leaves to wilt or discolour, heavily infested plants can die. Literature most commonly refers to damage to greenhouse grown potted ornamentals such as Cuphea, Hibiscus, Pelargonium and Phoenix. All life stages occur in the soil and host plants for planting with growing media provide a pathway for eggs, nymphs and adults. Multiple overlapping generations occur in greenhouses each year. R. hibisci is listed in Annex IIA of EU Regulation 2016/2031, appearing with the synonym Rhizoecus hibisci. All plants for planting from third countries are regulated. The import of soil or growing medium attached to plants for planting from third countries (other than Switzerland) is prohibited and therefore reduces the likelihood, but does not prevent entry of R. hibisci, as individuals may remain attached to the roots. There have been interceptions of R. hibisci in the EU, usually on artificially dwarfed plants, i.e. bonsai/penjing. Findings in EU greenhouses have been eradicated. R. hibisci would be able to establish in the EU, greenhouse potted plant production would be most affected. Phytosanitary measures are available to lower the likelihood of introduction. R. hibisci satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. R. hibisci does not meet the criterion of occurring in the EU for it to be regarded as a potential Union regulated non‐quarantine pest.

Abstract The EFSA Panel on Plant health was requested to prepare and deliver risk assessments for commodities listed in the relevant Implementing Acts as ‘High risk plants, plant products and other objects’ (Commission Implementing Regulation (EU) 2018/2019 establishing a provisional list of high‐risk plants, plant products or other objects, within the meaning of Article 42 of Regulation (EU) 2016/2031). The current scientific opinion covers all plant health risks posed by dormant bare rooted plants for planting of Malus domestica (1–2 years old) imported from Serbia, considering the available scientific information, including the technical information provided by the Plant Protection Directorate from Serbia on 27 December 2019. The relevance of an EU‐quarantine pest for this opinion was based on evidence that: (a) the pest is present in Serbia; (b) the pest uses M. domestica as a host; (c) one or more life stages of the pest can be associated with the specified commodity. The relevance for this opinion of pests not regulated in the EU was based on the following criteria: (i) the pest is present in Serbia; (ii) the pest is not present in the EU; (iii) M. domestica is a host of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose potential risk for the EU territory. After the assessment of 1191 potential pests, one bacterium, Erwinia amylovora, fulfilled all criteria and accordingly, was selected for further evaluation. For this bacterium, the risk mitigation measures proposed in the technical dossier were evaluated. Limiting factors on the effectiveness of the measures were also considered. For the selected species, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on E. amylovora, including any uncertainties. Based on the outcomes of an Expert Knowledge Elicitation, the Panel is considering a pallet as a unit; and taking into account the uncertainties associated with the assessment, the panel is 95% sure that 9,934 or more pallets out of 10,000 will be pest free.

Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. This Scientific Opinion covers all plant health risks posed by dormant and free of leaves, 1‐ to 3‐year‐old bare root plants for planting of Acer spp. imported from New Zealand, taking into account the available scientific information, including the technical information provided by New Zealand. The relevance of an EU‐quarantine pest for this opinion was based on evidence that: (i) the pest is present in New Zealand; (ii) Acer spp. are hosts of the pest and (iii) the pest can be associated with the commodity. The relevance for this opinion of any other pest, not regulated in the EU, was based on evidence that: (i) the pest is present in New Zealand; (ii) the pest is absent from the EU; (iii) Acer spp. are hosts of the pest; (iv) the pest can be associated with the commodity and (v) the pest may have an impact and can pose a potential risk for the EU territory. Four pests (Eotetranychus sexmaculatus, Meloidogyne fallax, Oemona hirta and Platypus apicalis) that fulfilled all relevant criteria were selected for further evaluation. For the selected pests, the risk mitigation measures proposed in the technical dossier from New Zealand were evaluated taking into account the possible limiting factors. For the selected pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. Based on the outcome of Expert Knowledge Elicitation, the degree of pest freedom varies among the pests evaluated. The mite, Eotetranychus sexmaculatus, was the pest most likely to cause plants to fail pest freedom status. The Panel is 95% sure that at least 9,240 plants per 10,000 will be free from E. sexmaculatus.

ABSTRACT High proliferation rate and robustness are vital characteristics of bacterial pathogens that successfully colonize their hosts. The observation of drastically slow growth in some pathogens is thus paradoxical and remains unexplained. In this study, we sought to understand the slow (fastidious) growth of the plant pathogen Xylella fastidiosa. Using genome-scale metabolic network reconstruction, modeling, and experimental validation, we explored its metabolic capabilities. Despite genome reduction and slow growth, the pathogen’s metabolic network is complete but strikingly minimalist and lacking in robustness. Most alternative reactions were missing, especially those favoring fast growth, and were replaced by less efficient paths. We also found that the production of some virulence factors imposes a heavy burden on growth. Interestingly, some specific determinants of fastidious growth were also found in other slow-growing pathogens, enriching the view that these metabolic peculiarities are a pathogenicity strategy to remain at a low population level. IMPORTANCE Xylella fastidiosa is one of the most important threats to plant health worldwide, causing disease in the Americas on a range of agricultural crops and trees, and recently associated with a critical epidemic affecting olive trees in Europe. A main challenge for the detection of the pathogen and the development of physiological studies is its fastidious growth, as the generation time can vary from 10 to 100 h for some strains. This physiological peculiarity is shared with several human pathogens and is poorly understood. We performed an analysis of the metabolic capabilities of X. fastidiosa through a genome-scale metabolic model of the bacterium. This model was reconstructed and manually curated using experiments and bibliographical evidence. Our study revealed that fastidious growth most probably results from different metabolic specificities such as the absence of highly efficient enzymes or a global inefficiency in virulence factor production. These results support the idea that the fragility of the metabolic network may have been shaped during evolution to lead to the self-limiting behavior of X. fastidiosa.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Naupactus leucoloma Boheman (Coleoptera: Curculionidae) for the EU territory. N. leucoloma is a polyphagous pest reported to feed on 385 plant species; cultivated hosts include alfalfa, beans, brassicas, carrots, clover, onions, peas, potatoes and soft fruits. N. leucoloma is native to eastern South America. During the first half of the 20th century, it spreads to Australia, New Zealand, South Africa and the USA. In 2005, it was reported in the Azores where it occurs in the wild. In suitable conditions, N. leucoloma can develop from egg to adult in about 12 months with adults emerging during spring and summer. Outside of South America only females are known, they develop and lay eggs without fertilisation. Eggs are usually laid in the soil but can be laid on the stem or lower leaves of hosts. Larval root feeding causes damage to root surfaces leading to stunting and yield or quality losses. Larvae can tunnel inside potato tubers causing significant losses. Pupation takes place in the soil in spring and summer. Larvae and eggs that are laid late in the summer overwinter. Plants for planting and plant products, such as potatoes, provide potential pathways for entry into the EU. The suitable climate and the wide availability of host plants provide conditions to support the establishment of N. leucoloma in the EU. N. leucoloma is regulated in the EU by Commission Implementing Regulation 2019/2072 (Annex IIA). The import of soil or growing medium, from third countries other than Switzerland, is prohibited in the EU and therefore so far inhibited the entry of N. leucoloma larvae and pupae. All criteria assessed by EFSA for consideration either as a potential union quarantine pest or as a potential regulated non‐quarantine pest are met.

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Exomala orientalis (Coleoptera: Rutelidae) (Oriental beetle) for the EU. Larvae feed on the roots of a variety of hosts including most grasses and many vegetable crops. Maize, pineapples, sugarcane are among the main host plants. Larvae are particularly damaging to turfgrass and golf courses. The adults feed on flowers and other soft plant tissues (e.g. Alcea rosea, Dahlia, Iris, Phlox and Rosa). Eggs are laid in the soil. Larvae feed on host roots and overwinter in the soil. Adults emerge from pupae in the soil in May‐June and are present for about 2 months. E. orientalis usually completes its life cycle in 1 year although individuals can spend two winters as larvae. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates E. orientalis. The legislation also regulates the import of soil attached to plants for planting from third countries; therefore, entry of E. orientalis eggs, larvae and pupae is prevented. E. orientalis is native to Japan or the Philippine islands. It is also found in East Asia and India, Hawaii and north‐eastern USA. It is assumed to have reached USA via infested nursery stock. Plants for planting (excluding seeds) and cut flowers provide potential pathways for entry into the EU. E. orientalis has been intercepted only once in the EU, on Ilex crenata bonsai. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. Impacts on maize, grassland and turfgrass would be possible. There is uncertainty on the extent of the impact on host plants which are widely commercially grown (e.g. maize) Phytosanitary measures are available to reduce the likelihood of entry. E. orientalis satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. Of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union regulated non‐quarantine pest, E. orientalis does not meet the criterion of occurring in the EU.