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Arbuscular mycorrhizal (AM) fungi play key roles in soil fertility of agroecosystems. They develop dense extraradical mycelial (ERM) networks via mechanisms such as hyphal anastomosis. These connections between hyphae can be afected by agricultural practices such as the use of fungicides, but how these compounds afect anastomosis formation within and more importantly between networks of the same AM fungal strain remains poorly unexplored. Here, the impact of azoxystrobin, pencycuron, futolanil, and fenpropimorph at 0.02 and 2 mg L−1 were tested in vitro on the anastomosis formation within and between networks of Rhizophagus irregularis MUCL 41833. Azoxystrobin and fenpropimorph had a particularly detrimental impact, at the highest concentration (2 mg L−1), on the number of anastomoses within and between networks, and for fenpropimorph in particular at both concentrations (0.02 and 2 mg L−1) on the number of anastomoses per length of hyphae. Curiously fenpropimorph at 0.02 mg L−1 signifcantly stimulated spore production, while with azoxystrobin, the reverse was observed at 2 mg L−1. The two other fungicides, pencycuron and futolanil, had no detrimental efects on spore production or anastomosis formation within and between networks. These results suggest that fungicides with diferent modes of action and concentrations diferentially afect anastomosis possibly by altering the hyphal tips of AM fungi and may thus afect the capacity of AM fungi to develop large hyphal networks exploring and exploiting the soil at the service of plants.

This article summarises the activities of the Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses for the period of March 2021−March 2022. We provide an overview of the new taxa proposed in 2021, approved by the Executive Committee, and ratified by vote in 2022. Significant changes to the taxonomy of bacterial viruses were introduced: the paraphyletic morphological families Podoviridae, Siphoviridae, and Myoviridae as well as the order Caudovirales were abolished, and a binomial system of nomenclature for species was established. In addition, one order, 22 families, 30 subfamilies, 321 genera, and 862 species were newly created, promoted, or moved.

The EFSA Panel on Plant Health performed a pest categorisation of Maconellicoccus hirsutus (Hemiptera: Pseudococcidae), the pink hibiscus mealybug, for the EU. M. hirsutus is native to Southern Asia and has established in many countries in tropical and subtropical regions throughout the world. Within the EU, the pest has been reported from Cyprus and Greece (Rhodes). M. hirsutus is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is highly polyphagous, feeding on plants assigned to 229 genera in 78 plant families, and shows some preference for hosts in the families Malvaceae, Fabaceae and Moraceae. Economically important crops in the EU such as cotton (Gossypium spp.), citrus (Citrus spp.), ornamentals (Hibiscus spp.), grapes (Vitis vinifera), soybean (Glycinae max), avocado (Persea americana) and mulberry trees (Morus alba) may be significantly affected by M. hirsutus. The lower and upper developmental temperature threshold of M. hirsutus on Hibiscus rosa‐sinensis are 14.5 and 35.0°C, respectively, with optimal female development estimated to be at 29.0°C. There are about 10 generations a year in the subtropics but as many as 15 may occur under optimal conditions. Plants for planting, fruits, vegetables and cut flowers provide potential pathways for entry into the EU. Climatic conditions in EU member states around the Mediterranean Sea and host plant availability in those areas are conducive for establishment. The introduction of M. hirsutus is expected to have an economic impact in the EU through damage to various ornamental plants, as already observed in Cyprus and Greece, and reduction in yield and quality of many significant crops. Phytosanitary measures are available to reduce the likelihood of entry and further spread. Some uncertainties include the area of establishment, whether it could become a greenhouse pest, impact, and the influence of natural enemies. M. hirsutus meets the criteria that are within the remit of EFSA to as

Rice stripe necrosis virus (RSNV) is the causal agent of the rice crinckle disease. Considered as an (re-)emerging virus in South America and West Africa, little data are available on the virus, and especially how the virus interact with its host plant and its plasmodiophorid vector, Polymyxa graminis. The tripartite interactions between RSNV, P. graminis and Oryza sativa has been investigated to confirm experimentally the acquisition and transmission of the virus by this vector protist. The analysis of the genetic diversity of the new sequences obtained, presents two main lineages of RSNV emerging in America and re-emerging in Africa. The genetic diversity of the RNA2 segment of RSNV and BNYVV were similar except for an in-frame insertion of 243 nucleotides located in the RSNV tgbp1 gene, whereas the RNA1 segment showed higher nucleotide variability for RSNV than for BNYVV. The RSNV transmission vector, P. graminis f. sp. colombiana, was found highly associated with Oryza sativa and O. glaberrima, but is also found, to a lesser extent, on a wider host range including Zea mays, Sorghum bicolor, Pennisetum glaucum, and Triticum durum as well as with some rice field weeds. while Polymyxa multiplies in different hosts, the virus is only transmitted to rice. Sequences of the 28 S, beta tubulin, eF1- alpha, L10 and RSP5 40s genes have been used in addition to the full-length sequences of ITS, and 5.8 S to propose a multi-locus sequence analysis as a tool for the precise diagnostic of rice associated Polymyxa. In this thesis, a first demonstration of the acquisition and transmission of RSNV by P. graminis under experimental conditions. The thesis is now opening the field for screening rice varieties for resistance against the virus and/or its vector, as well for proposing biologically based management strategies for the rice crinckle disease., (AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 2022

During a survey of polypores in the montane forest of the Ôbo de São Tomé National Park, in the western African, equatorial island of São Tomé, a specimen that was, a priori, related to Fomitopsis showed deviating features including subglobose basidiospores with a large gutta. The gross morphology of the basidiome, the hyphal system, the subglobose basidiospores and a brown rot pointed toward Niveoporofomes. Phylogenetic inferences based on multiple loci dataset (ITS-LSU-SSU-TEF1-RPB2) confirmed the placement, and Niveoporofomes oboensis is described as new. The species is compared to Fomitopsis widdringtoniae, known from southeast Africa, which is characterized also by subglobose basidiospores; hence, the new combination N. widdringtoniae is proposed. The new combination Niveoporofomes globosporus (basionym Trametes globospora) is also proposed based on phylogenetic analyses. A key to the species of Fomitopsis, Niveoporofomes, Rhodofomes and Rhodofomitopsis in Tropical Africa is presented.

The Xanthomonas translucens species comprises phytopathogenic bacteria that can cause serious damage to cereals and to forage grasses. So far, the genomic resources for X. translucens were limited, which hindered further understanding of the host–pathogen interactions at the molecular level and the development of disease-resistant cultivars. To this end, we complemented the available complete genome sequence of the X. translucens pv. translucens pathotype strain DSM 18974 by sequencing the genomes of all the other 10 X. translucens pathotype strains using PacBio longread technology and assembled complete genome sequences. Phylogeny based on average nucleotide identity (ANI) revealed three distinct clades within the species, which we propose to classify as clades Xt-I, Xt-II, and Xt-III. In addition to 2,181 core X. translucens genes, a total of 190, 588, and 168 genes were found to be exclusive to each clade, respectively. Moreover, 29 non-transcription activator-like effector (TALE) and 21 TALE type III effector classes were found, and clade- or strain-specific effectors were identified. Further investigation of these genes could help to identify genes that are critically involved in pathogenicity and/or host adaptation, setting the grounds for the development of new resistant cultivars.

Pinus armandii (P. armandii) is extensively abundant in western China and, as a pioneer tree, and prominently influences local ecology. However, pine forests in this region have been significantly damaged by Dendroctonus armandi (D. armandi) infestations, in close association with ophiostomatoid fungi. This study aimed to identify the diversity of ophiostomatoid fungi associated with D. armandi infesting P. armandii in western China. A total of 695 ophiostomatoid fungal strains were isolated from 1040 tissue pieces from D. armandi galleries and 89 adult beetles at four sites. In this study, based on multiloci DNA sequence data, as well as morphological and physiological characteristics, seven species belonging to five genera were identified including three known species, Esteyea vermicola, Graphium pseudormiticum and L. wushanense, two novel taxa, Graphilbum parakesiyea and Ophiostoma shennongense, and an unidentified Ophiostoma sp. 1. A neotype of Leptographium qinlingense. Ophiostoma shennongense was the dominant taxon (78.99%) in the ophiostomatoid community. This study provides a valuable scientific theoretical basis for the occurrence and management of D. armandi in the future.

Because of their increasing resistance to antibiotics, bacteria have become one of the top ten threats to global health according to the World Health Organisation [

Tuta absoluta (Lepidoptera: Gelechiidae) is a worldwide invasive insect species, considered a major pest of tomato. It has recently established in Burkina Faso, where chemical control remains the only affordable option to limit damages. Nesidiocoris tenuis (Hemiptera: Miridae) is commercialized as a biological agent to control this pest in other parts of the world. But very limited information exists on this predator in Burkina Faso. In this study, we first performed an insect survey in all agricultural regions areas of the country, and we found N. tenuis to be widely observed in all of them. Then, we performed two laboratory bioassays and demonstrated that all instars preyed on T. absoluta eggs, whether they were fed ad libitum or they had to actively forage for their prey. Because insecticide tolerant populations of T. absoluta were recently identified, we finally aimed at identifying agrochemicals that do not harm N. tenuis. We evaluated the toxicity of two synthetic insecticides, three bio-bacterial insecticides and eight plant extracts, all being active ingredients available on the local market. Most of them (i.e., abamectin, emamectin benzoate, spinosad, spinetoram) were highly toxic for both T. absoluta and N. tenuis. In contrast, Bacillus thuringiensis var. Kurstaki, neem oil, Cleome viscosa (Asian spiderflower), Ocimum basilicum (Basil) and Cassia occidentalis (Coffee senna) were compatible with N. tenuis while still controlling T. absoluta. Based on our results, we recommend the application of Bacillus thuringiensis to both control T. absoluta and which does not compromise the maintenance of N. tenuis populations.

Genomic knowledge of the tree of life is biased to specific groups of organisms. For example, only six full genomes are currently available in the rhizaria clade. Here, we have applied metagenomic techniques enabling the assembly of the genome of Polymyxa betae (Rhizaria, Plasmodiophorida) RES F41 isolate from unpurified zoospore holobiont and comparison with the A26–41 isolate. Furthermore, the first P. betae mitochondrial genome was assembled. The two P. betae nuclear genomes were highly similar, each with just ~10.2 k predicted protein coding genes, ~3% of which were unique to each isolate. Extending genomic comparisons revealed a greater overlap with Spongospora subterranea than with Plasmodiophora brassicae, including orthologs of the mammalian cation channel sperm-associated proteins, raising some intriguing questions about zoospore physiology. This work validates our metagenomics pipeline for eukaryote genome assembly from unpurified samples and enriches plasmodiophorid genomics; providing the first full annotation of the P. betae genome.

The chemical quality of soil carbon (C) inputs is a major factor controlling litter decomposition and soil C dynamics. Mycorrhizal fungi constitute one of the dominant pools of soil microbial C, while their litter quality (chemical proxies of litter decomposability) is understood poorly, leading to major uncertainties in estimating soil C dynamics. We examined litter decomposability of arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungal species using samples obtained from in vitro cultivation. We showed that the chemical composition of AM and EM fungal mycelium differs significantly: EM fungi have higher concentrations of labile (water-soluble, ethanol-soluble) and recalcitrant (non-extractable) chemical components, while AM fungi have higher concentrations of acid-hydrolysable components. Our results imply that differences in decomposability traits among mycorrhizal fungal guilds represent a critically important driver of the soil C cycle, which could be as vital as is recognized for differences among aboveground plant litter.

Phytophthora sojae is a pathogen of major agricultural importance, responsible for Phytophthora root rot (PRR) in soybean crops, which can cause significant yield losses each year. The severity of the disease depends on the soybean cultivar, its growth stage at the time of pathogen infection, and the environmental conditions. High soil moisture and temperature around 25–30 °C are favorable conditions for the development of the disease. Consequently, cultural practices are mainly limited to avoiding bad weather (high moisture) during the sowing or to promoting soil drainage. The use of chemical fungicides is restricted to seed treatments when there is a high risk of disease development. Currently the most economical option for controlling P. sojae is the use of host resistance. However, even if breeding is the main control strategy of PRR, the use of resistant cultivars leads to selection pressure on P. sojae populations, which can lead to high variability of the pathogen and therefore to its adaptation to overcome plant resistance. New strategies are therefore needed, including the use of biological control agents (BCAs). The use of BCAs (i.e., microorganisms or their metabolites) is a promising and sustainable alternative to PRR control that should be strengthened. Therefore, this review addresses the P. sojae–soybean interaction, mechanisms of pathogenicity and host resistance, as well as current and new management strategies with emphasis on the biological control of P. sojae and its associated mechanisms.

Anchusa officinalis (L.) interacts with various microorganisms including arbuscular mycorrhizal fungi (AMF). Recently, the AMF Rhizophagus irregularis MUCL 41833 has been shown to modulate the metabolome of A. officinalis. However, little information is available on the impact that different AMF species may have on primary and secondary plant metabolites. In this study, four AMF species belonging to the genus Rhizophagus (R. irregularis MUCL 41833, R. intraradices MUCL 49410, R. clarus MUCL 46238, R. aggregatus MUCL 49408), were evaluated for their potential to modulate A. officinalis metabolome under controlled semi-hydroponic cultivation conditions. An untargeted metabolomic analysis was performed using UHPLC-HRMS followed by a multivariate data analysis. Forty-two compounds were reported to be highly modulated in relation to the different AMF associations. Among them, six new secondary metabolites were tentatively identified including two acetyl- and four malonyl- phenylpropanoid and saponin derivatives, all presenting a common substitution at position C-6 of the glycosidic moiety. In addition, an enhanced accumulation of primary and secondary metabolites was observed for R. irregularis and R. intraradices, showing a stronger effect on A. officinalis metabolome compared to R. clarus and R. aggregatus. Therefore, our data suggest that different AMF species may specifically modulate A. officinalis metabolite production.

Microbial inoculants containing arbuscular mycorrhizal (AM) fungi are potential tools in increasing the sustainability of our food production systems. Given the demand for sustainable agriculture, the production of such inoculants has potential economic value and has resulted in a variety of commercial inoculants currently being advertised. However, their use is limited by inconsistent product efficacy and lack of consumer confidence. Here, we propose a framework that can be used to assess the quality and reliability of AM inoculants. First, we set out a range of basic quality criteria which are required to achieve reliable inoculants. This is followed by a standardized bioassay which can be used to test inoculum viability and efficacy under controlled conditions. Implementation of these measurements would contribute to the adoption of AM inoculants by producers with the potential to increase sustainability in food production systems.

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 defoliated and in dormant phase, grafted bare rooted plants for planting of Malus domestica imported from Moldova, taking into account the available scientific information, including the technical information provided by the applicant country. A list of 1,118 pests potentially associated with the commodity species was compiled. The relevance of these pests was assessed following defined criteria and based on evidence. The EU-quarantine pest Xiphinema rivesi non-EU populations fulfilled these criteria and was selected for further evaluation. For this pest, the risk mitigation measures proposed in the technical dossier from Moldova 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 it, including uncertainties associated with the assessment. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,991 and 10,000 plants per 10,000 would be free of X. rivesi.

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.

The EFSA Panel on Plant Health performed a pest categorisation of Toumeyella parvicornis (Cockerell) (Hemiptera: Coccidae) for the EU territory. This species is not included in EU Commission Implementing Regulation 2019/2072. T. parvicornis is a soft-scale insect native to North America and has been introduced to the Caribbean region and the EU. It has been present in Italy since 2014 (Abruzzo, Campania, Lazio, and Apulia regions) and in France since 2021 (Provence–Alpes–Côte d'Azur region) and is under official control. It develops on Pinus spp. (Pinaceae), feeding on the needles and twigs, especially on new growth. It is sexually reproductive, has one or more generations each year (three in southern Italy), and adult females overwinter on the Pinus needles. It has a high fecundity, up to 1,014 eggs per female in Italy, with an average of 199 eggs for the summer generation and 730 for the overwintering generation. The main natural dispersal stage is the first instar, which crawls over the plant or may be dispersed further by wind and animals. The species can be transported over longer distances with plants for planting. Large populations cause yellowing, needle loss, reduction in growth and recruitment, flagging, dieback and tree mortality. It has had a significant impact to P. pinea (stone pine) in Italy and caused a catastrophic decline of P. caribbea var. bahamensis (Caribbean pine) in the Turks and Caicos Islands. Adult and immature T. parvicornis could enter the EU with Pinus plants for planting; however, the import of Pinus from third countries where the scale is found is prohibited. Host availability and climate suitability indicate that most of the EU would be suitable for establishment. Phytosanitary measures are available to inhibit further introductions and slow the spread within the EU. T. parvicornis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

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 2-year-old bare rooted plants for planting of Acer palmatum grafted on rootstocks of Acer davidii imported from China to the EU, taking into account the available scientific information, including the technical information provided by China. All pests associated with the commodity were evaluated against specific criteria for their relevance for this Scientific Opinion. Twenty-two pests that fulfilled all relevant criteria were selected for further evaluation. For 20 pests, the risk mitigation measures described in the technical dossier from China 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. While the estimated degree of pest freedom varied among pests, Lopholeucaspis japonica was the pest most frequently expected on the commodity. The Expert Knowledge Elicitation indicated, with 95% certainty, that 9,336 or more bare rooted plants per 10,000 will be free from L. japonica. For Anoplophora chinensis and Anoplophora glabripennis, the Panel considers that China applies the relevant measures as specified in Commission Implementing Decision (EU) 2012/138 and Commission Implementing Decision (EU) 2015/893.

The EFSA Panel on Plant Health performed a pest categorisation of Russellaspis pustulans (Hemiptera: Asterolecaniidae), the oleander pit scale, for the EU. R. pustulans occurs widely in tropical and subtropical areas of the world and is restricted to indoor plantings in cooler temperate regions. Within the EU, it has been reported in some literature from Cyprus, Italy and Malta though not confirmed by the NPPOs. R. pustulans is not listed in Commission Implementing Regulation (EU) 2019/2072. It is very polyphagous, feeding on plants in 69 families and exhibits a preference for fig (Ficus carica) and oleander (Nerium oleander). R. pustulans was observed completing up to three generations per year in Egypt, with peaks of presence in June, October and December. The main natural dispersal stage is the first instar, which crawls over the host plant or may be dispersed further by wind and animals. Plants for planting, cut branches and fruits provide potential pathways for entry into the EU. Climatic conditions in some parts of southern EU countries are favourable and host plants are available in those areas to support establishment. However, the magnitude of impact following introduction is uncertain. Phytosanitary measures are available to reduce the likelihood of entry and further spread. R. pustulans does meet the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

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 unrooted cuttings of Jasminum polyanthum that are imported from Uganda, taking into account the available scientific information, including the technical information provided by the NPPO of Uganda. The relevance of any pest for this opinion was based on evidence following defined criteria. Six species, two EU-regulated pests (Bemisia tabaci, non-European populations and Scirtothrips dorsalis) and four EU non-regulated pests (Coccus viridis, Diaphania indica, Pulvinaria psidii and Selenaspidus articulatus), fulfilled all relevant criteria and were selected for further evaluation. For these pests, the risk mitigation measures proposed in the technical dossier from Uganda 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 B. tabaci and S. dorsalis being the pests most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,950 and 10,000 plants per 10,000 would be free of B. tabaci.

The EFSA Panel on Plant Health performed a pest categorisation of Plicosepalus acaciae (Zuccarini) Wiens & Polhill), the acacia strap flower, a hemiparasitic plant of the family Loranthaceae parasitising woody plants. Host plants include several species of the genera Vachellia, Tamarix and Ziziphus and various fruit crops. P. acaciae is present in the Middle East and Eastern Africa and is not known to occur in the EU. P. acaciae has a long flowering period of about 10 months, from June to April the following year, during which flowers are pollinated by insects and birds. P. acaciae produces single seeded red berries that are eaten by birds, which then disseminate the seeds. The only known bird observed to disseminate the seeds of P. acaciae is Pycnonotus xanthopygos, which has been recorded just once (Spain) but it is not established in the EU. P. acaciae could enter into the EU with host plants for planting. Host plants are present and suitable climatic conditions occur in parts of the EU. If a suitable bird would adapt to transfer the seeds, establishment and spread of P. acaciae within the EU would be possible. If P. acaciae would be able to establish and spread, impacts on some crop plants (e.g. Juglans regia, Ficus carica, Punica granatum, Pistacia vera), ornamental plants, as well as native vegetation could occur. P. acaciae fulfils the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest. Uncertainty remains on bird species other than P. xanthopygos transferring P. acaciae, the magnitude of potential impacts and the host range.

The EFSA Panel on Plant Health conducted a pest categorisation of Capsicum chlorosis virus (CaCV) for the EU territory. The identity of CaCV, a member of the genus Orthotospovirus (family Tospoviridae), is established and reliable detection and identification methods are available. The pathogen is not included in the EU Commission Implementing Regulation 2019/2072. CaCV has been reported in Australia, China, India, Iran, Taiwan, Thailand and USA (Hawaii). In the EU, it has been reported once in Greece (Crete Island). The NPPO of Greece reported that CaCV is no longer present in Greece. CaCV infects plant species in the family Solanaceae (i.e. pepper, tomato) and several species of other families, including ornamentals. It may induce severe symptoms on its hosts, mainly on leaves and fruits, which may become unmarketable. The virus is transmitted in a persistent propagative mode by the thrips Ceratothripoides claratris, Frankliniella schultzei, Microcephalothrips abdominalis and Thrips palmi. C. claratris and T. palmi are EU quarantine pests. M. abdominalis is known to be present in several EU member states and it is not regulated in the EU. Plants for planting, parts of plants, fruits and cut flowers of CaCV hosts, and viruliferous thrips were identified as the most relevant pathways for the entry of CaCV into the EU. Cultivated and wild hosts of CaCV are distributed across the EU. Should the pest enter and establish in the EU territory, impact on the production of cultivated hosts is expected. Phytosanitary measures are available to prevent entry and spread of the virus in the EU. CaCV fulfils the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in the Commission Implementing Regulation (EU) 2018/2019 as ‘High-risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by potted plants (2–4 years old) of specified Lonicera species produced in nurseries and that are imported from Turkey, taking into account the available scientific information, including the technical information provided by the NPPO of Turkey. The relevance of any pest for this Opinion was based on evidence following defined criteria listed in Section 4.1. Three species, the EU-quarantine pests Lopholeucaspis japonica and Meloidogyne chitwoodi and the protected zone quarantine pest Bemisia tabaci, fulfilled these 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 B. tabaci on evergreen species of Lonicera spp. being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,293 and 10,000 plants per 10,000 would be free of B. tabaci.

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 dormant grafted plants, rootstocks, budwood and scions of Malus domestica imported from Turkey, taking into account the available scientific information, including the technical information provided by Turkey. All pests associated with the commodities were evaluated against specific criteria for their relevance for this opinion. Three quarantine pests (Anoplophora chinensis, Lopholeucaspis japonica and tomato ringspot virus), one protected zone quarantine pest (Erwinia amylovora) and eight non-regulated pests (Calepitrimerus baileyi, Cenopalpus irani, Cicadatra persica, Diplodia bulgarica, Hoplolaimus galeatus, Malacosoma parallela, Pratylenchus loosi and Pyrolachnus pyri) that fulfilled all relevant criteria were selected for further evaluation. For E. amylovora, special requirements are specified in Commission Implementing Regulation (EU) 2019/2072. Based on the information provided in the dossier, the specific requirements for E. amylovora were not met. For Anoplophora chinensis, special measures are specified in Commission Implementing Decision (EU) 2012/138. The exporting country does meet the requirement for a certificate regarding plants for planting that originate from Turkish provinces other than Istanbul. For the 10 remaining selected pests, the risk mitigation measures proposed in the technical dossier from Turkey 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 D. bulg

The EFSA Panel on Plant Health performed a pest categorisation of Bagrada hilaris (Hemiptera: Pentatomidae) for the EU territory. B. hilaris, known as the bagrada bug or painted bug, is a polyphagous pest feeding on at least 25 plant families including several economically important brassica crops such as broccoli, cabbage and cauliflower. Other economically important hosts suffering impacts include beans (Fabaceae), wheat and maize (Poaceae). Young plants are particularly vulnerable to adults and nymphs feeding on tender leaves and growing points, which can cause yield losses. B. hilaris occurs in Africa and Asia and has spread to North America (USA and Mexico) and South America (Chile) where there are multiple generations per year. It is not widely distributed in the EU but has been established in Malta and on the Italian island of Pantelleria, south west of Sicily, since the 1970s where it is an economically important pest of capers. The reasons why it has not spread further within southern Europe are unknown. B. hilaris is not a regulated pest in the EU. It could further enter and spread within the EU via the import and movement of host plants or as a hitchhiking species forming aggregations in conveyances and amongst non‐plant traded goods. Host availability and climate suitability suggest that, in addition to Malta and Pantelleria, southern areas of the EU around the Mediterranean would also be suitable for B. hilaris establishment. The introduction of B. hilaris to other Mediterranean areas of the EU would likely cause impacts in a range of crops, particularly brassicas. Measures to prevent entry and spread are available. B. hilaris satisfies all of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Following a request from the EU Commission, the EFSA Panel on Plant Health conducted a pest categorisation of Apium virus Y (ApVY) for the EU territory. The identity of the ApVY, a member of the genus Potyvirus (family Potyviridae), is well established and reliable detection methods are available. The pathogen is not included in EU Commission Implementing Regulation 2019/2072. ApVY, considered endemic in Australia, was reported also in New Zealand and USA. In the EU, the virus was identified in Germany and Slovenia. No information on adoption of official control measures is available. In natural conditions, ApVY infects plant species of the family Apiaceae (i.e. celery, coriander, dill, parsley, bishop’s weed) in which it generally induces leaf symptoms and/or stunting. In some hosts (i.e. parsley and poison hemlock), ApVY may be asymptomatic. The virus is transmitted in a non-persistent manner by the aphid Myzus persicae which is widespread in the EU. Although ApVY transmission through seeds has been experimentally excluded for some hosts (i.e. poison hemlock and celery), uncertainty exists for the other hosts because seed transmission is not uncommon for potyvirids. Plants for planting, including seeds for sowing, were identified as potential pathways for entry of ApVY into the EU. Cultivated and wild hosts of ApVY are distributed across the EU. Economic impact on the production of the cultivated hosts is expected if further entry and spread in the EU occur. Phytosanitary measures are available to prevent further entry and spread of the virus. Currently, ApVY does not fulfil the criterion of being absent or present with restricted distribution and under official control to be regarded as a potential Union quarantine, unless official control is implemented. This conclusion is associated with high uncertainty regarding the current virus distribution in the EU.

The EFSA Panel on Plant Health performed a pest categorisation of Zaprionus indianus (Diptera: Drosophilidae), the African fig fly for the territory of the EU. This species successfully colonised the Indian subcontinent more than four decades ago, and more recently South and North America. Within the EU, the pest occurs in Cyprus, Malta, Portugal (Madeira) and Spain (Canary Islands and Andalusia). Z. indianus is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. The larvae of this fly feed on more than 80 plant species both cultivated and non-cultivated. Females produce around 60–70 eggs. Egg laying mostly occurs in decaying fruit or fruit with injuries or mechanical damage. However, Z. indianus can oviposit on undamaged healthy fruit such as figs, strawberries and guavas which provide a potential pathway for entry into the EU. Lower temperature thresholds are around 9–10°C. Optimum development occurs at 28°C. The number of generations per year varies from 12 to 16. Climatic conditions in many EU member states and host plant availability in those areas are conducive for establishment. The introduction of Z. indianus is expected to have an economic impact in the EU especially on fig and strawberry production. Damage caused by other fruit flies (Drosophilidae and Tephritidae) could be increased by mixed infestations. Phytosanitary measures are available to reduce the likelihood of entry and further spread. Z. indianus satisfies all of the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver a scientific opinion on the risk posed by bonsai plants from China consisting of Pinus parviflora grafted on Pinus thunbergii taking into account the available scientific information, including the technical information provided by China. All pests associated with P. parviflora and/or P. thunbergii were evaluated against specific criteria for their relevance for this Scientific Opinion. Forty-three pests that fulfilled all relevant criteria were selected for further evaluation. For 24 pests that are not quarantine in the EU, the risk mitigation measures described in the technical dossier from China 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. While the estimated degree of pest freedom varied among pests, Setoptus parviflorae was the pest most frequently expected on the commodity. The Expert Knowledge Elicitation indicated, with 95% certainty, that 9,114 or more bonsai plants per 10,000 will be free from Setoptus parviflorae. For 19 pests that are quarantine in the EU, the implementation of specific measures defined in point 30 and 31 of Annex VII of Commission Implementing Regulation (EU) 2019/2072 was evaluated. The requirements of point 31 are met, whereas those of point 30 are not completely fulfilled.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in the Commission Implementing Regulation (EU) 2018/2019 as ‘High-risk plants, plant products and other objects’. This Scientific Opinion covers plant health risks posed by potted plants (2–3 years old) of Berberis thunbergii produced in nurseries and imported into the EU from Turkey, taking into account the available scientific information, including the technical information provided by the NPPO of Turkey. The relevance of any pest for this Opinion was based on evidence following defined criteria. Two species, the EU-quarantine pest Bemisia tabaci and the non-regulated pest Malacosoma parallela, fulfilled the 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 B. tabaci being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9,928 and 10,000 plants per 10,000 would be free of B. tabaci. The role of Berberis thunbergii as possible host of Puccinia spp. is discussed in the body of the opinion.

The EFSA Panel on Plant Health performed the pest categorisation of the ulluco weevil, Amathynetoides nitidiventris (Hustache), for the EU territory. This species is not included in EU Commission Implementing Regulation 2019/2072. However, its only substantiated host, ulluco (Ullucus tuberosus), is included in Annex I of Regulation EU 2018/2019 as a high risk plant prohibited from entering the EU, pending risk assessment. In its native Andean region, A. nitidiventris is univoltine, with a lifecycle highly synchronised with the phenology of its host, reproduction and development take place during the development of tubers. Oviposition occurs in the soil. Larvae feed by tunnelling into the tubers, which most of them abandon to pupate in the soil. A minority pupates in the tubers. Because adult A. nitidiventris are often found in other crops due to crop rotations and crop associations, this species has been mistakenly identified as a pest of other crops. In principle soil and tubers of ulluco could provide a pathway for A. nitidiventris into the EU. However, the soil pathway is closed and ulluco tubers are regulated as high risk plants. There are no EU records of interception. Should this weevil enter the EU, the rarity of its host, which is not known to be cultivated in EU MSs, would hamper establishment, spread, and impact. As a consequence, A. nitidiventris does not satisfy all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. The criteria that are not met are the potential for establishment, spread, and economic or environmental consequences in the EU.

The EFSA Panel on Plant Health performed a pest categorisation of Atalodera andina (Nematoda: Heteroderidae) for the European Union (EU) territory. A. andina belongs to the order Rhabditida, subfamily Ataloderinae. This species has not been reported from the EU. It is not included in the EU Commission Implementing Regulation 2019/2072. It is present in the area of the Lake Titicaca of both Peru and Bolivia and in valleys of the region. There is a report in literature stating that specimens were obtained from Chile and identified as A. andina but details on their geographical origin were not given. The identity of A. andina is well established and methods of its identification are available. Natural hosts include the tuber crops Ullucus tuberosus, Oxalis tuberosa and the Andean potato (Solanum tuberosum subsp. andigenum). Experimental hosts include plants of the genus Brassica (such as B. oleracea, B. napus, B. campestris), sugar beet, tomato and clover. Pathways of entry are host plants for planting including seed tubers, subterranean parts of plants intended for consumption, soil as such or attached to plants for planting, machinery or footwear, soil in packaging (bags). Suitable climates exist in the EU but their extent is uncertain and depends on assumptions made on the occurrence of the pest around Lake Titicaca. In the EU, potato, which is grown on about 1,500,000 ha annually, is expected to be the main host of the nematode. Soil and plants for planting are prohibited from import to the EU from third countries where the pest is known to occur. However, this does not cover hosts of A. andina other than species of Solanaceae. The nematode has been reported to damage Andean potato crops, although this has not been quantified. Following its introduction in the EU, A. andina is expected to cause impacts on potato (S. tuberosum subsp. tuberosum), although there is uncertainty on the magnitude of this impact. Also damage on other hosts cannot be excluded. Therefore, t

The EFSA Panel on Plant Health performed a pest categorisation of Sirex nitobei (Hymenoptera: Siricidae), the nitobe horntail, for the territory of the EU. S. nitobei is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072 but was identified as a potential regulated pest in a commodity risk assessment of Pinus thunbergii artificially dwarfed plants from Japan. This species is present in Japan (except Hokkaidō), the Republic of Korea and 13 Chinese provinces. S. nitobei attacks several Pinus species and has been reported less frequently on Abies firma and Larix spp., including L. leptolepis. The females oviposit into the sapwood. Eggs are deposited together with a phytotoxic mucus and a symbiotic fungus, Amylostereum areolatum or A. chailletii. The combined action of the venom and the fungus results in the death of the host trees. The fungus degrades the lignocellulosic components of the wood, and the larvae feed on the liquid fraction of the digested residues left by the fungus. All immature stages live in the hosts sapwood. The lifecycle of the pest lasts 1 year. S. nitobei can travel with conifer wood, wood packaging material or plants for planting, but these pathways from third countries are closed by prohibition. However, a derogation exists for artificially dwarfed Japanese black pine (Pinus thunbergii) from Japan, which therefore provides a potential pathway. Climatic conditions in several EU member states and host plant availability in those areas are conducive for establishment. The introduction of S. nitobei is potentially damaging for pines. Phytosanitary measures are available to reduce the likelihood of entry and further spread, and there is a potential for biological control. S. nitobei satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The EFSA Panel on Plant Health performed a pest categorisation of Pseudococcus cryptus Hempel (Hemiptera: Pseudococcidae), the citriculus mealybug, for the EU. P. cryptus originates from Southeast Asia but is now established in East Africa, the Middle East and South America. The pest is not currently known to occur in the EU (there was a record once, in 2006, in a zoo/botanical garden from southern Spain). P. cryptus is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in more than 90 genera in 51 families, and exhibits a preference for citrus (Citrus spp.) and palms (especially Cocos nucifera, Elaeis guineensis and Areca catechu). It is an important pest of citrus in Japan and parts of the Middle East, although in Israel, it is controlled by natural enemies. It is sexually reproductive, has six overlapping generations each year in Israel, and each female lays up to approximately 150 eggs, depending on temperature and host species. The main natural dispersal stage is the first instar, which crawls over the host plant or may be dispersed further by wind and animals. Plants for planting, fruits, vegetables and cut flowers provide potential pathways for entry into the EU. Climatic conditions in EU member states around the Mediterranean Sea where there is host plant availability, especially citrus, are conducive for establishment. The introduction of P. cryptus is expected to have an economic impact in the EU through reduction in yield and quality of important crops (mainly citrus) and damage to various ornamental plants. Phytosanitary measures are available to reduce the likelihood of entry and further spread. P. cryptus meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

The EFSA Panel on Plant Health performed a pest categorisation of Oligonychus perseae (Acari: Prostigmata: Tetranychidae), the persea mite, for the EU. O. perseae is a tropical species that originated in Mesoamerica and has now spread and established in California, Florida, Hawaii, Morocco, southern Europe and Israel. Within the EU, it is established in Italy, Portugal and Spain. O. perseae is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in 20 genera in 17 families. It is most frequently reported on avocado (Persea americana), where it is considered a key pest. No evidence was found indicating damage to other crops. O. perseae live on leaves and do not attack the fruit. Populations usually grow exponentially at the beginning of summer and decline at the end of this season. High population densities can cause severe defoliation, resulting in downgrading of fruit through sunburn. However, this type of damage is common only if trees additionally suffer from water stress. The lack of additional avocado pests in the EU, which facilitates the production of organic avocados, is jeopardised by the occurrence of this mite, as it may require pesticide applications. This is why O. perseae is considered an important pest of avocados in Spain, where more than 80% of EU avocado production occurs. Natural dispersal is restricted to neighbouring trees. However, human-assisted movement can result in long-distance spread. Plants for planting provide potential pathways for further entry and spread, including O. perseae-free EU MS where avocados are grown (i.e. Cyprus, France, Greece). Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the likelihood of further entry and spread. O. perseae satisfies with no key uncertainties the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union qu

The EFSA Panel on Plant Health performed a pest categorisation of Aulacaspis tubercularis (Hemiptera: Diaspididae), the white mango scale, for the EU. A. tubercularis is a tropical species that originates from Asia but is now established in several tropical and subtropical regions throughout the world. It also occurs within the EU and is established in Italy, Portugal and Spain. A. tubercularis is not listed in Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on plants in more than 37 genera in 23 families and is most frequently reported on mango (Mangifera indica). Indeed, it is considered one of the key pests of mango crops around the world. No evidence was found indicating damage to crops other than mango. A. tubercularis is established in southern Spain (Andalusia) with four overlapping generations and two population peaks, one in summer and another in autumn. Andalusia is the main mango producing area of the EU and A. tubercularis can cause losses through downgrading of fruit. The main natural dispersal stage is the first instar, which crawls over the host plant or may be dispersed further by wind and animals. Plants for planting and fruits provide potential pathways for further entry and spread. Climatic conditions and availability of host plants in southern EU countries are conducive for establishment. Phytosanitary measures are available to reduce the likelihood of further entry and further spread. A. tubercularis satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The EFSA Panel on Plant Health performed a pest categorisation of the Japanese grape leafhopper, Arboridia kakogawana (Matsumura, 1932) (Hemiptera: Cicadellidae), for the EU territory. This species is not included in the EU Commission Implementing Regulation 2019/2072. Adults of A. kakogawana overwinter in broad-leaved and mixed forests and move to vineyards in the spring where there may be up to four generations, before adults move back to forests during late summer–early autumn to overwinter, possibly under diapause. A. kakogawana has a restricted host range (Vitis spp. and Parthenocissus quinquefolia). It is native to Eastern Asia, from where it moved westwards reaching southern Russia in 1999, and subsequently Ukraine, Romania, Bulgaria and Serbia in 2020. A. kakogawana develops on the abaxial side of the leaves causing chlorotic spots that reduce grape quality. Plants for planting of Vitis L. are banned from entering the EU except from Switzerland, where A. kakogawana is not known to occur. Therefore, this can be considered as a closed entry pathway. However, other plants for planting including the host P. quinquefolia and many broad-leaved trees where overwintering takes place, as well as isolated bark and wood with bark provide potential pathways which are partly regulated but remain open. There are no EU records of interception. Additional introductions and further spread of A. kakogawana into/within the EU, coupled with the ample availability of grapevines and the climatic conditions would most probably allow successful establishment in most EU member states. Should this happen, economic impact in table and wine grapes is anticipated. A. kakogawana satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest (UQP).

The phage replication cycle begins with its adsorption to its host and ends with the release of new virions upon bacterial lysis. These steps are important, not only for the proper conduct of the phage life cycle, but also because proteins mediating attachment and lysis have a significant biotechnological potential. The adsorption step involves viral proteins called receptor binding proteins (RBP) and specific receptors at the host surface, while membrane permeabilization and cell wall degradation leading to lysis are achieved by the concerted actions of holins and endolysins. This thesis aimed to better understand the adsorption and lysis processes of phages targeting the Bacillus cereus group. The first part of this work showed that phage Deep-Blue is a promising candidate for controlling emetic strains, although its narrow host range requires its integration in a phage cocktail. In the second part, the viral proteins involved in the adsorption process were investigated. Comparison of the tail proteins of B. cereus siphoviruses revealed diverse genetic organizations and the prevalence of carbohydrate binding modules (CBM). The role in adsorption of these CBM was experimentally demonstrated for phage Deep-Purple. Regarding myoviruses, Deep-Blue and Vp4 RBP were identified, and their tail regions compared to that of the well-known Listeria phage A511 revealing important differences in key proteins. The third part of this thesis showed that different lysis mechanisms are present in phages infecting B. cereus and that endolysins have a broader activity spectrum than their related phages revealing that they could be used in biocontrol and detection., (AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 2022

The EFSA Plant Health Panel performed a pest categorisation of Fusarium pseudograminearum O'Donnell & T. Aoki. F. pseudograminearum is a soil-borne fungal pathogen, able to cause a disease known as Fusarium crown rot (FCR, also known as foot and root rot) and occasionally Fusarium head blight on small grain cereals, particularly Triticum aestivum L., Triticum turgidum L. spp. durum (Dest.), Hordeum vulgare L. and triticale (xTriticosecale). In addition, F. pseudograminearum has been isolated from soybean (Glycine max L.) and from some grass genera, such as Phalaris, Agropyron and Bromus, which represent potentially important inoculum reservoirs. This pathogen has been reported in arid and semi-arid cropping regions in Australia, New Zealand, North and South America, northern Africa and South Africa, the Middle East and Asia. In the EU, it has been reported in Italy since 1994 and later in Spain on field-grown durum wheat, but uncertainty remains regarding the actual distribution of the pathogen in the EU. The pathogen is not included in the EU Commission Implementing Regulation 2019/2072. Seeds of host plants and soil and other substrates are the main pathways for the entry and spread of the pathogen into the EU. There are no reports of interceptions of F. pseudograminearum in the EU. Host availability and climate suitability occurring in the EU favour establishment of the pathogen and allow it to establish in areas from which it has not been reported. Phytosanitary measures are available to prevent the introduction of the pathogen into the EU, and additional measures are available to mitigate the risk of spread. In the non-EU areas of its present distribution, the pathogen has a direct impact on cultivated hosts (e.g. wheat, barley, triticale and soybean) that are also relevant for the EU. However, no crop losses have been reported so far in the EU. The Panel concludes that F. pseudograminearum satisfies all the criteria to be regarded as a potential Union quaranti

The EFSA Panel on Plant Health conducted a pest categorisation of High Plains wheat mosaic virus (HPWMoV) for the EU territory. The identity of HPWMoV, a member of the genus Emaravirus (family Fimoviridae), is well established and reliable identification methods are available. The pathogen is not included in the EU Commission Implementing Regulation 2019/2072. HPWMoV has been reported from Argentina, Australia, Canada, Ukraine and USA, and it is not known to be present in the EU. HPWMoV infects plant species of the family Poaceae (i.e. wheat, maize and several other cultivated or wild Poaceae species). It is the causal agent of High Plains disease of wheat and maize, inducing symptoms ranging from mild to severe mosaic, chlorosis and necrosis in wheat, and chlorotic streaks in maize plants. The virus is transmitted by the wheat curl mite Aceria tosichella, which is present in the EU. HPWMoV transmission via seeds was reported to occur in sweet corn. Sweet corn seeds for sowing were identified as the most relevant pathway for entry of HPWMoV into the EU. Seeds from other hosts and viruliferous wheat curl mites were identified as entry pathways associated with uncertainties. Machinery not appropriately cleaned may move infected seeds and/or parts of cereals infested by viruliferous mites. Cultivated and wild hosts of HPWMoV are distributed across the EU. Would the pest enter and establish in the EU territory, economic impact on the production of cultivated hosts is expected. Phytosanitary measures are available to prevent entry and spread of the virus in the EU. HPWMoV fulfils the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The EFSA Plant Health Panel performed a pest categorisation of Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4), an ascomycete fungus causing Fusarium wilt (Panama disease) on Musa spp. Foc TR4 is pathogenic to the commercial banana varieties including those of the ‘Cavendish’ group and is considered as the most destructive among Foc haplotypes. Uncertainty exists on the host range of Foc TR4, since it has not been demonstrated whether it can infect plant species other than Musa spp., which were previously reported as hosts of other Foc races. Foc TR4 is morphologically and physiologically identical to other representatives of the Fusarium oxysporum Species Complex (FOSC), but all Foc TR4 isolates belong to a single clonal lineage within the vegetative compatibility groups 01213-01216. Several PCR protocols are described in the literature, but their specificity has been questioned as they may generate false positives. The pathogen is not included in EU Commission Implementing Regulation 2019/2072 and is not reported as present in the EU territory. Several potential entry pathways and means of spread were identified, including host plants for planting other than vitroplants, fresh fruits and leaves of host plants, soil and other substrates originating in infested third countries. Host availability and climate suitability occurring in some areas of the EU are favourable for the establishment of Foc TR4. Being a soil-borne pathogen, eradication of Foc TR4 once it enters a new area is very difficult. Therefore, effective quarantine measures are essential in pathogen-free areas. Although not specifically targeting against Foc TR4, phytosanitary measures are currently available to prevent the introduction of the pathogen into the EU. Considering that banana-growing EU countries account for over 12% of the EU banana supply, it is expected that the economic impact of Foc TR4 on the European banana production areas would be devastating. Foc TR4 satisfies the crite

Lignin is the most abundant source of renewable aromatics on Earth, but its tendency to undergo irreversible condensation reactions during lignocellulose pretreatment hampers its valorization in current biorefinery schemes. A strategy for circumventing this issue is the so-called reductive catalytic fractionation (RCF), which relies on the use of redox catalysts and hydrogen gas to promote the reductive cleavage of lignin and to prevent lignin condensation, ultimately yielding low-molecular weight phenolics, along with a delignified (hemi)cellulose fraction. Some limitations must be overcome to improve the potential of RCF. The treatment of biomass feedstocks alternative to the widely explored virgin wood is important for extending the range of applications of this method. In addition, the recurrent adoption of high pressures of hydrogen gas poses safety and equipment constraints. This dissertation reports on research undertaken to investigate the RCF of wheat straw, an inexpensive and abundantly available agricultural residue, with a focus on the study of hydrogen-free process configurations. Moreover, an innovative dithionite-assisted organosolv fractionation (DAOF) method for the reductive depolymerization of lignin within biomass pretreatment is developed, based on the use of sodium dithionite as a reducing agent, instead of hydrogen gas and redox catalysts. Overall, this dissertation shows that RCF and DAOF represent promising approaches for the sustainable production of light aromatics via the reductive depolymerization of lignin., (AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 2022

The European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), commonly known as the forest tent caterpillar, for the territory of the EU. M. disstria is a North American polyphagous leaf-eating pest primarily feeding on deciduous trees belonging to the genera Acer, Malus, Populus, Prunus, Quercus and Tilia. It is a univoltine species. Eggs are laid on twigs and branches. Larvae emerge in the spring to feed on buds and fresh leaves. Host plants can be completely defoliated although they often refoliate and recover within a few weeks. Nevertheless, three consecutive years of heavy defoliation or repeated periods of defoliation combined with drought can cause extensive tree mortality. As such, M. disstria is regarded as one of the most serious hardwood forestry insect pests in North America. Population upsurges leading to outbreaks are cyclical, generally nine to 13 years apart and can last 2–3 years. Outbreaks have been reported in eastern North America since the late 18th century. Outbreaks in western Canada have spanned up to 200,000 km2. Plants for planting, cut branches and isolated bark provide pathways for entry. Host availability and climate suitability suggest that large parts of the EU would be suitable for establishment. The pest could spread naturally by flight within the EU. Eggs on plants for planting could also facilitate spread. The introduction of M. disstria into the EU could lead to serious outbreaks causing significant damage to forest, orchard and amenity trees and shrubs. Phytosanitary measures are available to inhibit the entry and spread of this species. M. disstria satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Modeling the potential spread of Xylella fastidiosa can document contingency plans in northern Europe, so far uncolonized by the bacterium. Through mark–release–recapture (MRR) and flight-mill experiments, the flight capacity of two potential vectors for temperate Europe was studied: Philaenus spumarius, the reported southern European vector, and Aphrophora salicina, a xylem-specialist feeding on potential host plants of X. fastidiosa. Aphrophora salicina displayed significantly better flight performances than P. spumarius. In flight-mills, the average distance flown was, respectively, 623 m vs. 102 m and the maximal distance flown was 6.16 km vs. 1.54 km in 2.5 h. In MRRs, A. salicina travelled more than 30 m in a single flight, with a maximal interception distance of 80 m after two days, highlighting that dispersal is driven by connectivity and host plant quality. Philaenus spumarius mainly jumped, with 1 m movements in length and a maximal interception distance of 32 m in 27 days. Models estimated P. spumarius' daily mean dispersal at 1.5 m and A. salicina's at 3.5 m. Although only a small part of the population moves over very long distances, this pool of efficient insects could already be sufficient to effectively spread an epidemic. As Salicaceae have been reported as host plants of the bacterium, the association of Aphrophoridae and Salicaceae in riparian areas could create bacterium reservoirs in corridors allowing for transportation over medium to long distances.

Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) reached West Africa in 2012 and has since become a major tomato pest. Various alternative strategies for pest control have been identified worldwide, including crop rotation, to deprive the insect of its food. However, this method can only be implemented if a good knowledge of the local host plants of the leafminer have been identified. Here, we have assessed the capacity of Tuta absoluta to develop on 27 common vegetable crops in West Africa, representing the Poaceae, Apiaceae, Convolvulaceae, Amaranthaceae, Malvaceae, Lamiaceae, Cucurbitaceae, Fabaceae, Brassicaceae, Asteraceae, Solanaceae, and Amaryllidaceae. The tomato leafminer was only able to develop and complete its life cycle on crops within the genus Solanum. Among the 27 plant species tested, Solanum lycopersicum L. (tomato) was identified as the best host, allowing for rapid development (22.2 ± 1.4 days) and a high survival rate (84%). Solanum tuberosum L. (Irish potato) (24.4 ± 0.8 days; survival rate 40%), Solanum aethiopicum L. (African eggplant) (24.3 ± 0.6 days; survival rate 52%) and Solanum melongena L. (eggplant) (25.9 ± 1.8 days; survival rate 24%) were three other possible hosts. Larval development occurred on onion (Allium cepa L.), but not pupation. A strategy that includes a prolonged absence of the genus Solanum in a production area would be associated with a considerable reduction in leafminer population size.

The development of biomass pretreatment approaches that, next to (hemi)cellulose valorization, aim at the conversion of lignin to chemicals is essential for the long-term success of a biorefinery. Herein, we discuss a dithionite-assisted organosolv fractionation (DAOF) of lignocellulose in n-butanol and water to produce cellulosic pulp and mono-/oligo-aromatics. The study frames the technicalities of this biorefinery process and relates them to the features of the obtained product streams. We comprehensively identify and quantify all products of interest: solid pulp (acid hydrolysis-HPLC, ATR-FTIR, XRD, SEM, enzymatic hydrolysis-HPLC), lignin derivatives (GPC, GC–MS/FID, 1H–13C HSQC NMR, ICP-AES), and carbohydrate derivatives (HPLC). These results were used for inspecting the economic feasibility of DAOF. In the best process configuration, a high yield of monophenolics was reached (∼20 wt%, based on acid insoluble lignin in birch sawdust). Various other lignocellulosic feedstocks were also explored, showing that DAOF is particularly effective on hardwood and herbaceous biomass. Overall, this study demonstrates that DAOF is a viable fractionation method for the sustainable upgrading of lignocellulosic biomass.

Xylella fastidiosa, a plant-pathogenic bacterium colonizing xylem and transmitted by insects, is involved in severe outbreaks worldwide. X. fastidiosa establishes in a wide range of conditions including different host plants and vector species, making it highly unpredictable in not yet colonized areas. A quarantine agent in Europe, it has recently been reported as a pest in several Mediterranean European areas, raising questions about the risk of a potential expansion up North. This work investigates the possibility of X. fastidiosa establishing in northern temperate Europe by examining the potential host range and potential insect vectors in these areas. Three different tools were used to investigate host range: mechanical inoculation, transmission via infected vectors, and sentinel plantation. These trials revealed that the Salicaceae include suitable host species that can be colonized by the bacterium, such as Populus tremula and Salix alba. On the other hand, the mobility of two potential insect species for these regions was investigated: Philaenus spumarius and Aphrophora salicina, through flight-mill and mark-release-recapture experiments. Driven by willow distribution, A. salicina proved to be a good flyer. Associated with Salicaceae, this species could transport the bacterium over medium or long distances on plants forming linear corridors in riparian areas or in alignments along crops. These environments could act as reservoirs from which polyphagous vectors as P. spumarius could transmit the bacterium on a local scale to economically important crops. This study highlights one possible scenario and pathosystem for potential long-term establishment and spread of Xylella-related diseases in northern temperate Europe., (AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 2022

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a worldwide invasive pest of tomatoes (Solanum lycopersicum L.) that reached West Africa in 2010. Synthetic insecticides remain the most widely used method of control, but several biological alternatives are being developed. In this work, we evaluated nine biopesticides available on the West African market for their ability to control T. absoluta. Using standard leaf or egg dip bioassay methodology, we compared both the ovicidal and the larvicidal activity of these biopesticides at various concentrations of active ingredients. We found that, for each biopesticide tested, the larval lethal concentrations (LC) (8.2–41.14 ml/L) to be lower than those necessary to stop egg hatching (26.7–409.7 ml/L). Two products (Bangr-Kièta [BK]; Bangr-Pougo [BP], formulated in powder), both based on Azadirachta indica A. Jussieu fruit and leaf extracts and Khaya senegalensis (Desrousseaux) A. Jussieu bark extract, showed high efficacy in reducing egg hatchability at their recommended doses, with a calculated control failure likelihood (CFL) reaching 0%. These two products, together with a third one (BP) based on Mitracarpus scaber Zuccarini and K. senegalensis extracts, also showed the strongest larvicidal effects (CFL = 0%). All other tested biological insecticides showed significant efficiency but were found to be less effective at their recommended doses. Because the leafminer has developed resistance to most of the synthetic insecticide available on the market, we recommend that West African tomato producers are encouraged to use the most efficient biological products available.