International Plant Trade Research Articles

Multiplex PCR specific for genus Phytophthora and P. nicotianae with an internal plant DNA control for effective quarantine of Phytophthora species in Japan

To prevent threats from pathogens such as Phytophthora species from international plant trade, molecular identification techniques are needed for rapid, accurate quarantine inspection. Here, for quarantine control in Japan, we developed a simple DNA extraction for plants and a practical detection method that combines multiplexed PCR using primers specific for Phytophthora species, for P. nicotianae, which is the only non-quarantine Phytophthora species, and as internal controls, for plants. For the new genus-level primer set, we modified previously reported genus-specific primers to improve detectability. The new primers were able to detect mycelial DNA of 155 taxa among Phytophthora clades 1–10, with a sensitivity of 100 fg/µL for three representative species, P. ramorum, P. kernoviae and P. nicotianae. In the PCRs using DNA from non-target species, amplification was observed for only three taxa, and for some strains, four taxa in a closely related genus. Duplex and triplex PCR of the genus-specific primers combined with previously reported plant primers verified the success of DNA extraction and PCR detection from diseased plant samples, and in the triplex PCR, whether the pathogen was diagnosed as P. nicotianae or not by the species-specific primer. The new method detected the pathogen in naturally infected and inoculated plants. The amplicons using the genus-specific primer have enough variation to be sequenced to identify the species. This new method can be used immediately for detecting Phytophthora species and for quarantine control in Japan.

The first host plant dataset of Curculionidae Scolytinae of the world: miscellaneous Tribes

Tribes Coriacephilini, Corthylini, Cryphalini, Ernoporini, Trypophloeini, Xyloctonini, and Xyloterini (Coleoptera: Curculionidae; Scolytinae) include spermophagous, phloeophagous, and xylomycetophagous species. Besides direct damage caused by burrowing into host plant tissues, some species are vectors of aggressive pathogens causing plant dieback and death, with consequent economic and ecological relevance. The international trade in plants and wood products is one of the main pathways for the introduction of non-native species worldwide. In this context, data availability on host plants and their economic uses is essential in pest risk assessment and for planning effective detection and monitoring strategies against invasive species. This paper provides a complete and updated list of host plants, with economic categorization, for 2139 scolytine species.

Can the Seed Trade Provide a Potential Pathway for the Global Distribution of Foliar Pathogens? An Investigation into the Use of Heat Treatments to Reduce Risk of Dothistroma septosporum Transmission via Seed Stock.

The international plant trade results in the accidental movement of invasive pests and pathogens, and has contributed significantly to recent range expansion of pathogens including Dothistroma septosporum. Seeds are usually thought to present a lower biosecurity risk than plants, but the importation of Pinus contorta seeds from North America to Britain in the mid-1900s, and similarities between British and Canadian D. septosporum populations suggests seeds could be a pathway. Dothistroma septosporum has not been isolated from seeds, but inadequately cleaned seed material could contain infected needle fragments. This case study investigated whether cone kilning, and wet and dry heat treatments could reduce D. septosporum transmission without damaging seed viability. Pinus needles infected with D. septosporum were incubated alongside cones undergoing three commercial seed extraction processes. Additional needles were exposed to temperatures ranging from 10 to 67 °C dry heat for up to 48 h, or incubated in water heated to between 20 and 60 °C for up to one hour. Pinus sylvestris seeds were exposed to 60 and 65 dry heat °C for 48 h, and further seed samples incubated in water heated to between 20 and 60 °C for up to one hour. Dothistroma septosporum survived the three kilning processes and while seeds were not damaged by dry heat exceeding 63.5 °C, at this temperature no D. septosporum survived. Wet heat treatments resulted in less than 10% pathogen survival following incubation at 40 °C, while at this temperature the seeds suffered no significant impacts, even when submerged for one hour. Thus, commercial seed kilning could allow D. septosporum transmission, but elevated wet and dry heat treatments could be applied to seed stock to minimise pathogen risk without significantly damaging seed viability.

Evidence of a Natural Hybrid Oomycete Isolated from Ornamental Nursery Stock

The oomycete genus Phytophthora includes many plant pathogens important in agricultural and environmental systems. Natural interspecific hybridization has been reported several times in Phytophthora, and although the fundamental processes of interspecific hybridization and the consequences of subsequent ecological distribution are poorly understood, reports suggest some hybrids can infect a broader host range and display enhanced virulence compared to the putative parental species. During a survey carried out at the University of Aberdeen in 2014–2015, of oomycetes present in ornamental plants purchased via the internet, a batch of oomycete isolates remained unidentified, showing, in some isolates, features generally related to hybridization. The aim of this study was to determine whether hybridization events had occurred between endemic and introduced oomycetes, probably/possibly facilitated through the international plant trade. The list of isolates examined included a putative hybrid closely related to Phytophthora cryptogea. The putative hybrid isolate was further characterized, and pathogenicity were tests carried out on Eucalyptus globulus, using an isolate of P. cryptogea as a positive control. Cloning of ITS, COXI and β-tubulin genes resulted in different sequence versions of the putative hybrid isolate; after mapping and a polymorphism position comparison, it was concluded that the studied isolate contained genetic information from P. cryptogea, P. erythroseptica, P. kelmanii, P. sansomeana and Phytopythium chamaehyphon. A PCR-RFLP assay, a NEBcutter analysis and flow cytometry analysis (genomes ranged between 0.168 to 0.269 pg/2C) added further evidence of the hybrid nature of this isolate. The putative hybrid presented complex growing patterns ranging from rosaceous to chrysanthemum-like and had an optimum growth temperature of 25 °C. Although the putative hybrid produced visible symptoms of disease on E. globulus seedlings, assessment of the relative susceptibility of E. globulus to P. cryptogea and the putative hybrid indicated that P. cryptogea was significantly more virulent than the putative hybrid, based on mortality, disease severity and foliar symptoms.

Survival of Phytophthora cryptogea and Phytophthora cactorum in Commercial Potting Substrates for Eucalyptus globulus Plants

The international plant trade is considered to be the main pathway causing the spread of oomycetes internationally, especially when live plants are accompanied by soil or potting substrates. Modern, rapid shipping technologies, together with inadequate management practices in nurseries, increase the probability of survival of plant pathogens and the subsequent chances of disease outbreaks in new locations. The survival of two oomycete soil-borne pathogens, Phytophthora cryptogea and Phytophthora cactorum, was studied in two different commercial potting substrates (peat-based and peat-free) in the absence of a plant host under simulated nursery conditions in a glasshouse for 21 months. Colony forming units (CFUs) of both pathogens were recovered 21 months after substrate inoculation, with a decrease in CFUs of between 92 and 99%, depending on the pathogen and substrate. Eucalyptus globulus plants were then planted into these inoculated pots. After 21 months, P. cryptogea and P. cactorum remained capable of producing diseases in E. globulus plants, resulting in up to 30% mortality and an up to 5-fold greater disease severity. These results highlight the ability of these pathogens to survive in the absence of a suitable host plant in potting substrates over time and to then have the capacity to infect a plant. This research adds to the body of essential evidence that is required to develop meaningful management practices and potting substrates at the nursery level to minimize the risk of the spread of oomycetes through the international plant trade.

Global predictions for the risk of establishment of Pierce’s disease of grapevines

The vector-borne bacterium Xylella fastidiosa is responsible for Pierce’s disease (PD), a lethal grapevine disease that originated in the Americas. The international plant trade is expanding the geographic range of this pathogen, posing a new threat to viticulture worldwide. To assess the potential incidence of PD, we have built a dynamic epidemiological model based on the response of 36 grapevine varieties to the pathogen in inoculation assays and on the vectors’ distribution when this information is available. Key temperature-driven epidemiological processes, such as PD symptom development and recovery, are mechanistically modelled. Integrating into the model high-resolution spatiotemporal climatic data from 1981 onward and different infectivity (R0) scenarios, we show how the main wine-producing areas thrive mostly in non-risk, transient, or epidemic-risk zones with potentially low growth rates in PD incidence. Epidemic-risk zones with moderate to high growth rates are currently marginal outside the US. However, a global expansion of epidemic-risk zones coupled with small increments in the disease growth rate is projected for 2050. Our study globally downscales the risk of PD establishment while highlighting the importance of considering climate variability, vector distribution, and an invasive criterion as factors to obtain better PD risk maps.

Monilinia fructicola intercepted on Prunus spp. imported from Spain into South Africa between 2010 and 2020

The international trade of plants and their products, such as fresh fruits, can facilitate the introduction and spread of foreign pests and diseases. We examined South Africa’s import of stone fruits (Prunus spp.) as a pathway for introducing Monilinia fructicola (G. Wint.) Honey and document recommended phytosanitary measures to deal with the risk associated with its exportation into the country. Fresh fruits of Prunus spp. are imported from various countries. The current study provides a report on 10 years (2010–2020) importation of Prunus spp. from Spain to South Africa with associated cases of M. fructicola. We also detail the current management measures for imported stone fruits from Spain to South Africa. We report 18 M. fructicola detections that were found during the study period. The number of detections presents enough trends to determine the level of phytosanitary concerns regarding the importation of Prunus spp. fresh fruit from Spain, which cannot be neglected. M. fructicola is an economically important brown rot on many fruit hosts and potentially threatens agricultural and horticultural industries, the environment, and biodiversity in South Africa. The importation of Prunus spp. requires intensive management strategies for M. fructicola, as pathogens may pose a major phytosanitary concern because it could thrive and reproduce in various environmental conditions and on various host plants in South Africa. Therefore, if M. fructicola establishes in South Africa, its impacts will have consequences for different key socioeconomic sectors, including the agricultural industry. Significance: Monilinia fructicola is a pest of quarantine significance for South Africa. If not managed properly, the importation of Prunus with associated M. fructicola will be a significant phytosanitary concern that could cause severe economic impacts on the South African agricultural industry.

Millipedes and centipedes (Myriapoda: Diplopoda, Chilopoda) in Swiss heated greenhouses, with seven species new for Switzerland

The international plant trade provides opportunities for the introduction of exotic species into tropical greenhouses around the world. The millipede and centipede fauna of greenhouses is barely known in Switzerland. We conducted a survey in greenhouses of nine botanical gardens and other institutions across Switzerland. We captured and identified 1390 individuals belonging to 14 millipede species and 43 individuals belonging to 9 centipede species. Most millipede individuals recorded (80.3%) were non-native as were the species (8/14). Most centipede individuals (55.3%) were non-native, but not the majority of the species (4/10). The species composition varied strongly among greenhouses with species originating from different parts of the world. Seven species already known from greenhouses in other European countries are reported for the first time in Switzerland. These are the millipedes Cylindrodesmus hirsutus Pocock, 1889, Poratia obliterata (Kraus, 1960), Paraspirobolus lucifugus (Gervais, 1836) and the centipedes Mecistocephalus guildingii Newport, 1843, Tygarrup javanicus Attems, 1929, Lamyctes (Lamyctes) coeculus (Brölemann, 1889b), and Cryptops (Cryptops) doriae Pocock, 1891. The relevance of these findings is discussed.

Worldwide diversity of endophytic fungi and insects associated with dormant tree twigs

International trade in plants and climate change are two of the main factors causing damaging tree pests (i.e. fungi and insects) to spread into new areas. To mitigate these risks, a large-scale assessment of tree-associated fungi and insects is needed. We present records of endophytic fungi and insects in twigs of 17 angiosperm and gymnosperm genera, from 51 locations in 32 countries worldwide. Endophytic fungi were characterized by high-throughput sequencing of 352 samples from 145 tree species in 28 countries. Insects were reared from 227 samples of 109 tree species in 18 countries and sorted into taxonomic orders and feeding guilds. Herbivorous insects were grouped into morphospecies and were identified using molecular and morphological approaches. This dataset reveals the diversity of tree-associated taxa, as it contains 12,721 fungal Amplicon Sequence Variants and 208 herbivorous insect morphospecies, sampled across broad geographic and climatic gradients and for many tree species. This dataset will facilitate applied and fundamental studies on the distribution of fungal endophytes and insects in trees.

Prvi nalazi vrsta Acizzia uncatoides (Ferris & Klyver, 1932) i Acizzia acaciaebaileyanae (Froggatt, 1901) (Hemiptera: Psylloidea: Psyllidae) u Hrvatskoj

Alien species represent a significant component of European entomofauna. Intensive international trade of plants, particularly woody ornamentals, has increased introduction of alien species into Europe in the last two decades, where alien terrestrial invertebrates prevail as one of the most numerous groups of introduced organisms. As of 2010, fourteen species of alien psyllids (Hemiptera: Psylloidea) have been recorded in Europe. Five species have been reported from Croatia, including Acizzia jamatonica (Kuwayama, 1908), as the only species from genus Acizzia Heslop-Harrison, 1961 present in Croatia so far. This paper provides genus status in Croatia, with first records of Australian species Acizzia uncatoides (Ferris & Klyver, 1932) and Acizzia acaciaebaileyanae (Froggatt, 1901).

Peptide-Based Identification of Phytophthora Isolates and Phytophthora Detection in Planta.

Phytophthora is arguably one of the most damaging genera of plant pathogens. This pathogen is well suited to transmission via the international plant trade, and globalization has been promoting its spread since the 19th century. Early detection is essential for reducing its economic and ecological impact. Here, a shotgun proteomics approach was utilized for Phytophthora analysis. The collection of 37 Phytophthora isolates representing 12 different species was screened for species-specific peptide patterns. Next, Phytophthora proteins were detected in planta, employing model plants Solanum tuberosum and Hordeum vulgare. Although the evolutionarily conserved sequences represented more than 10% of the host proteome and limited the pathogen detection, the comparison between qPCR and protein data highlighted more than 300 protein markers, which correlated positively with the amount of P. infestans DNA. Finally, the analysis of P. palmivora response in barley revealed significant alterations in plant metabolism. These changes included enzymes of cell wall metabolism, ROS production, and proteins involved in trafficking. The observed root-specific attenuation in stress–response mechanisms, including the biosynthesis of jasmonates, ethylene and polyamines, and an accumulation of serotonin, provided the first insight into molecular mechanisms behind this particular biotic interaction.

Phylogenetic inference enables reconstruction of a long-overlooked outbreak of almond leaf scorch disease (Xylella fastidiosa) in Europe

The recent introductions of the bacterium Xylella fastidiosa (Xf) into Europe are linked to the international plant trade. However, both how and when these entries occurred remains poorly understood. Here, we show how almond scorch leaf disease, which affects ~79% of almond trees in Majorca (Spain) and was previously attributed to fungal pathogens, was in fact triggered by the introduction of Xf around 1993 and subsequently spread to grapevines (Pierceʼs disease). We reconstructed the progression of almond leaf scorch disease by using broad phylogenetic evidence supported by epidemiological data. Bayesian phylogenetic inference predicted that both Xf subspecies found in Majorca, fastidiosa ST1 (95% highest posterior density, HPD: 1990–1997) and multiplex ST81 (95% HPD: 1991–1998), shared their most recent common ancestors with Californian Xf populations associated with almonds and grapevines. Consistent with this chronology, Xf-DNA infections were identified in tree rings dating to 1998. Our findings uncover a previously unknown scenario in Europe and reveal how Pierce’s disease reached the continent.

International wildlife trade, avian influenza, organised crime and the effectiveness of CITES: The Chinese hwamei as a case study

The Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) is the most important global initiative to monitor and regulate the international trade of plants and animals, but there is a lack of (retrospective) assessments of the effectiveness of its actions. We here focus on the international trade in Chinese hwamei Garrulax canorus, a songbird native to south-eastern China and northern Lao PDR and Vietnam. Prior to the year 2000, the species was heavily traded as an ornamental cage bird, both in countries within and outside its natural range. In an effort to prevent international overexploitation, at the request of China, the Chinese hwamei was listed in Appendix II of CITES, regulating all international trade. Here we compare data from three non-range countries (Thailand, Singapore and Indonesia) for which we have bird market survey data prior to and following the CITES listing. In addition, we assess whether or not CITES import and export figures agree with observations in the bird markets, and explore the contemporary (online) trade and trafficking in Chinese hwamei. We find a clear effect of the CITES listing and Chinese export restrictions in Indonesia (before ~50 birds/survey vs ~15 birds/survey after), but not in Thailand (~10 vs ~13) and Singapore (~4 vs ~16). Singapore is the only country that reports the import of Chinese hwamei, 1650 birds in 2002–2004 only, possibly accounting for a proportion of the birds observed in trade. In contrast, neither Thailand nor Indonesia report the import of a single Chinese hwamei since its CITES listing, despite some 2000 birds having been recorded openly for sale, suggesting large-scale illegal international trade in the species. Five seizures in Singapore and Indonesia were mostly because of concern about avian influenza. Price data, corrected for inflation, suggests that prices for Chinese hwamei have increased substantially, albeit following a delay, from ~US$50 prior to the listing to ~ US$200 after. We conclude that the CITES Appendix II listing of Chinese hwamei has had some positive effect on reducing the volumes of these birds in international trade, mainly through implementation of domestic legislation in China, but that substantial illegal or undocumented trade persists in Southeast Asia, involving organised criminal networks. We recommend actions from range countries, such as China, to cease the illegal export of Chinese hwamei, from importing countries such as Indonesia, to ensure no illegal shipments of birds enter their country, and for consumer countries where the species cannot legally be traded to curb the illegal domestic trade as the demand for songbirds in these markets drives the trafficking.

Pathogen Population Biology Research can Reduce International Threats to Tree Health Posed by Invasive Fungi

Humankind owes much to trees, given their major role in sequestering carbon and providing oxygen, sugars and much of the energy on which ourselves and terrestrial ecosystems depend. Trees and forests are important culturally, economically, environmentally and socially. And yet, despite this, trees throughout the world are currently facing an increasing number of serious challenges. On a global scale, Curtis et al. (2018) report most forest loss is due to commodity driven deforestation through permanent conversion to nonforest land uses including agriculture (e.g. palm oil production), energy production and mining. The other main drivers of global forest loss, that might instead be considered less permanent and associated with subsequent regrowth, include forestry, shifting agriculture and wildfire. Additional threats to forests include those posed by climate change, and invasive biotic agents such as insect pests and pathogens. Most new tree disease outbreaks are due to introduction events, with a potential pathogen introduced from their endemic centres of origin (where they generally cause little or no disease on their plant host due to long-term coevolution) into a new geographic location, in which a naive host has not previously been exposed and can thus be highly susceptible. The incidence of such 'new encounter' diseases is increasing at an unprecedented rate due to globalisation with increased international trade in plants and travel, a scenario potentially exacerbated by a changing climate better suited to establishment of a pathogen once introduced. Identification of the centres of origin of fungal pathogens can be important for several reasons. First, given that the original host-fungus interaction will have typically stabilised over long periods of time, such geographic regions could be useful sources of host genetic resistance. Moreover, the longer time periods involved will have likely resulted in greater genetic diversity accruing in such endemic populations. More diverse pathogen populations have greater evolutionary potential, with increased genetic variation available for response to environmental change. This could enable host tolerance to be overcome, unexpected 'jumps' onto new hosts, increased risk of fungicide resistance, and better adaptability to changing environmental conditions (e.g. temperature). Thus, strategies to reduce introduction of additional genetic variation from source to sink regions can reduce tree health threats. In this article, such introduction events are considered in the context of three devastating tree diseases, namely ash dieback, Dutch Elm Disease (DED) and Dothistroma Needle Blight (DNB, mainly on pine). On all these tree hosts, multiple closely-related fungal species have now been associated with each of these different diseases. Such related species are often morphologically very similar or even indistinguishable by eye, and consequently this can result in taxonomic confusion and species misidentification, leading to delayed diagnosis of the true causal agent of a given disease outbreak. Research into such related species is important as they might pose very different plant health threats that require distinct disease management strategies. These differences might relate to pathogenicity, geographic distribution, host range, effectiveness of host resistance, sensitivity to fungicides, temperature optima, reproductive strategy and so on. Furthermore, when related fungal species come into physical contact with each other after a long period of separation, for instance via an introduction event, various outcomes are possible including: (1) replacement (and possible extinction) of one species by the other; (2) coexistence of the species; or (3) cross-species hybridisation. The remainder of this article focuses, using three major tree disease case histories, on how fundamental research on pathogen biology can provide new insights into the genetic structure of related pathogen populations that can be usefully applied to reduce the threat to tree health posed by invasive fungal species.

High vegetative compatibility diversity of Cryphonectria parasitica infecting sweet chestnut (Castanea sativa) in Britain indicates multiple pathogen introductions

Chestnut blight, caused by Cryphonectria parasitica, was identified in Devon, UK, in December 2016. Intensive surveys detected the disease at further sites in Devon (seven), Berkshire (one), Dorset (one), Derbyshire (four) and a cluster of eight sites in southeast London. Over 570 survey samples were tested, and 227 were positive for C. parasitica by isolation and real‐time PCR. A total of 227 isolates were tested for mating type, and 197 screened for vegetative compatibility group (VCG) and compared with VCGs known from mainland Europe. The same isolates were also screened for the presence of Cryphonectria hypovirus 1 (CHV‐1). Eleven VCGs were identified within the UK population. Five corresponded to already known European VCGs but six were unique. The European VCGs mainly came from the Devon, Dorset, Berkshire and Derbyshire disease outbreaks, whilst unique VCGs were almost exclusively from the southeast London cluster. Both mating types were detected, but only one mating type was present at each site, with the exception of a single Devon site. Perithecia of C. parasitica were never observed at any site. CHV‐1 was found in seven isolates from three different locations and was always subtype‐I, which has limited hypovirulence. Therefore, although CHV‐1 is associated with C. parasitica at some outbreaks, it probably has limited impact on virulence. The diversity of VCGs and their distribution at outbreak sites, together with findings of CHV‐1, suggests C. parasitica has been introduced to the UK multiple times over at least two decades through international plant trade.

Survival ofPhytophthora cinnamomiandFusarium verticillioidesin commercial potting substrates for ornamental plants

Live plants, particularly when accompanied by soil or potting substrates, are considered the main pathway for international spread of plant pathogens. Modern, rapid shipping technologies for international plant trade increase the probability of plant pathogen survival during transport and the subsequent chances of disease outbreaks in new locations. The survival of two model pathogens, an Oomycete, Phytophthora cinnamomi, and a filamentous fungus, Fusarium verticillioides, was studied in two different commercial potting substrates (peat and peat-free) under glasshouse conditions in the absence of a plant host. Survival rates were analysed at 2, 7, 12 and 17 months after substrate inoculation. Fusarium verticillioides had the longest survival rate, and was still present at 17 months. In contrast, P. cinnamomi survived up to 7 months but was not recovered after 12 or 17 months. There was no significant difference in the number of colony-forming units (CFUs) of either pathogen in the two substrates, except at 2 months, when higher numbers were recovered from peat substrates.

Interception of weevils on cut flowers from South Africa by Korea plant quarantine

In 2015, a total of 31 samples belonging to superfamily Curculionoidea (Coleoptera) were intercepted from the cut flowers imported from South Africa at the Korean quarantine border. These samples were identified based on the available literature, and they were confirmed as 11 species belonging to four families. However, only three species were identified at the species level. The others were only classified into seven genera and one tribe level. Until now, there have been very few studies about weevils distributed in Africa. Consequently, there is a lack of available information for species identification of intercepted weevils at the quarantine border. This study aims to raise public awareness regarding the introduction of unwanted insect pests from the international trade of plants and/or plant products. It also suggests the need for international cooperation and taxonomic networking for the identification of intercepted pests.

A risk categorisation and analysis of the geographic and temporal dynamics of the European import of plants for planting

The international trade in plants for planting (P4Ps) is a major pathway for the introduction of plant pests. The global trade in P4Ps is both voluminous and highly diverse, but there is little detailed knowledge about its diversity and dynamics. This makes it difficult to assess the risks associated with this trade and to prioritise high-risk commodities (genus-origin combinations) for detailed inspection or regulation. Using the ISEFOR database, this paper describes the diversity and dynamics of P4P imports into the EU, based on genus-level data for lots imported into fourteen Member States that provided this data for different periods between 2005 and 2014, totalling over 30Bn plants and over 7500 commodities. There was great variety, as well as complementarity, in terms of the imported genera, origins and commodities among the countries. Two-thirds of the imported commodities changed every year. Based on the 10-year data from the Netherlands, the greatest importer of live plants in the dataset, we developed a risk categorisation approach for prioritising the highest risk commodities, based on risk associated information concerning the imported genus and the history of trade with respect to the exporting countries, genera and type of plant material traded. Application of this risk categorisation led to the identification of a modest number of commodities that represent elevated risk, to which more inspection resources can be allocated while lower-risk commodities could be subject to less-intensive phytosanitary inspections.

The first record of a potential pest Orientus ishidae (Matsumura, 1902) (Hemiptera: Cicadellidae) in Poland

Abstract This study provides the first data on the occurrence of the mosaic leafhopper Orientus ishidae (Matsumura, 1902) (Hemiptera: Cicadellidae) in Poland. This species is native to Southeast Asia, adventive in Europe and feeds on cultivated plants. Orientus ishidae is a well-known carrier of Grapevine flavescence doree phytoplasma which causes the grapevine yellows disease. Symptoms of phytoplasma diseases of grapevine include deformations, leaf chlorosis and withering of plants. The appearance of this species in Poland might be caused by observed climate variations and insufficient plant health controls in the international trade of plants.

A new approach to horizon-scanning: identifying potentially invasive alien species and their introduction pathways

Invasive alien species (IAS) are considered an important threat to global biodiversity due to major ecological impacts. In 2014, the European Union (EU) introduced a regulation (EU) No 1143/2014 on the prevention and management of the introduction and spread of IAS. The first risk prioritized list of IAS of EU concern was adopted on the 3rd of August 2016. EU member states are required within 18 months to carry out a comprehensive analysis and prioritisation of the pathways of unintentional introduction and spread of these IAS in their territory. Horizon-scanning is a method of IAS prioritisation through the systematic analysis of potential future IAS and identification of new opportunities for IAS management. However, horizon-scanning has mostly been applied on a national basis only, leading to a fragmented approach within the EU and ignoring the potential for IAS to cross international borders. We present a novel framework for horizon-scanning applicable at a continental scale. Our method maximises the use of available data from climatically matched countries by applying a harmonisation and aggregation method, and elucidates the relationship between pathways, impact types and species groups for risk prioritised IAS. Application of the method produced a list of potential IAS for the Netherlands revealing that the international trade in plants and animals is the most important pathway for the introduction of IAS. The horizon-scanning provided a starting point for the design of preventative, early identification and rapid action measures for the effective management of potential IAS.