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.
Experimental data on the relationship between plant patch size and population density of herbivores within fields often deviates from predictions of the theory of island biogeography and the resource ...concentration hypothesis. Here we argue that basic features of foraging behaviour can explain different responses of specialist herbivores to habitat heterogeneity. In a combination of field and simulation studies, we applied basic knowledge on the foraging strategies of three specialist herbivores: the cabbage aphid (Brevicoryne brassicae), the cabbage butterfly (Pieris rapae L.) and the diamondback moth (Plutella xylostella L.), to explain differences in their responses to small scale fragmentation of their habitat. In our field study, populations of the three species responded to different sizes of host plant patches (9 plants and 100 plants) in different ways. Densities of winged cabbage aphids were independent of patch size. Egg-densities of the cabbage butterfly were higher in small than in large patches. Densities of diamondback moth adults were higher in large patches than in small patches. When patches in a background of barley were compared with those in grass, densities of the cabbage aphid and the diamondback moth were reduced, but not cabbage butterfly densities. To explore the role of foraging behaviour of herbivores on their response to patch size, a spatially explicit individual-based simulation framework was used. The sensory abilities of the insects to detect and respond to contact, olfactory or visual cues were varied. Species with a post-alighting host recognition behaviour (cabbage aphid) could only use contact cues from host plants encountered after landing. In contrast, species capable with a pre-alighting recognition behaviour, based on visual (cabbage butterfly) or olfactory (diamondback moth) cues, were able to recognise a preferred host plant whilst in flight. These three searching modalities were studied by varying the in flight detection abilities, the displacement speed and the arrestment response to host plants by individuals. Simulated patch size - density relationships were similar to those observed in the field. The importance of pre- and post- alighting detection in the responses of herbivores to spatial heterogeneity of the habitat is discussed.
The increase in arrivals of new forest pests highlights the need for effective phytosanitary legislation and measures. This paper introduces legislation targeted at prevention and management of ...potential introductions of forest pests and pathogens. An overview is given on plant health regulations on global and regional level with detailed information on the situation in the European Union (EU). The current and new European legislation is discussed, and a particular focus is given on eradication and contingency plans for Fusarium circinatum. We identified key aspects relevant for the improvement of the efficacy of measures aimed to prevent alien pests.
This Guidance describes a two‐phase approach for a fit‐for‐purpose method for the assessment of plant pest risk in the territory of the EU. Phase one consists of pest categorisation to determine ...whether the pest has the characteristics of a quarantine pest or those of a regulated non‐quarantine pest for the area of the EU. Phase two consists of pest risk assessment, which may be requested by the risk managers following the pest categorisation results. This Guidance provides a template for pest categorisation and describes in detail the use of modelling and expert knowledge elicitation to conduct a pest risk assessment. The Guidance provides support and a framework for assessors to provide quantitative estimates, together with associated uncertainties, regarding the entry, establishment, spread and impact of plant pests in the EU. The Guidance allows the effectiveness of risk reducing options (RROs) to be quantitatively assessed as an integral part of the assessment framework. A list of RROs is provided. A two‐tiered approach is proposed for the use of expert knowledge elicitation and modelling. Depending on data and resources available and the needs of risk managers, pest entry, establishment, spread and impact steps may be assessed directly, using weight of evidence and quantitative expert judgement (first tier), or they may be elaborated in substeps using quantitative models (second tier). An example of an application of the first tier approach is provided. Guidance is provided on how to derive models of appropriate complexity to conduct a second tier assessment. Each assessment is operationalised using Monte Carlo simulations that can compare scenarios for relevant factors, e.g. with or without RROs. This document provides guidance on how to compare scenarios to draw conclusions on the magnitude of pest risks and the effectiveness of RROs and on how to communicate assessment results.
This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2018.EN-1440/full
‘This guidance supersedes:
a) the entire Guidance on a harmonised framework for pest risk assessment and the identification and evaluation of pest risk management options by EFSA. https://doi.org/10.2903/j.efsa.2010.1495;
b) Sections 1.8 and 1.9 of Guidance on methodology for evaluation of the effectiveness of options for reducing the risk of introduction and spread of organisms harmful to plant health in the EU territory. https://doi.org/10.2903/j.efsa.2012.2755’
Managing outbreaks of alien plant pests is key to preserving biodiversity and safeguarding crop production. Zoning strategies are applied by plant health authorities to tailor measures to the risk of ...spread in relation to distance from the outbreak epicentre and the biology of the pest. Here we synthesize information on outbreak management to evaluate the diversity and consistency of such approaches. We collected information on the zoning strategies of 121 outbreaks of 25 plant pests in the European Union (EU). According to the organism’s presence and the measures applied, five zones were distinguished: an infested zone (83% of cases), a buffer zone (76%), a clear-cutting zone (28%), an eradication zone (1%) and a containment zone (1%). Infested zones and buffer zones were adjacent non-overlapping zones, while the clear-cutting zone, eradication zone or containment zone was within either the infested zone or buffer zone. A combination of infested and buffer zones was used in 51% of recorded cases. Measures differed within different zones. Destruction of infested plants in the infested zone was done in 78% of the cases, while surveillance was always applied in the buffer zone. Regulation of an organism at EU level led to a convergence of zoning strategies applied by different member states. Regulations often prescribed the greatest widths used before regulations were issued. Further analyses are needed to explore the efficacy of different strategies including the costs of each strategy. Such analyses should combine insight from practice with bio-economic modelling.
EFSA was asked for a partial risk assessment of Spodoptera frugiperda for the territory of the EU focussing on the main pathways for entry, factors affecting establishment, risk reduction options and ...pest management. As a polyphagous pest, five commodity pathways were examined in detail. Aggregating across these and other pathways, we estimate that tens of thousands to over a million individual larvae could enter the EU annually on host commodities. Instigating risk reduction options on sweetcorn, a principal host, reduces entry on that pathway 100‐fold. However, sweetcorn imports are a small proportion of all S. frugiperda host imports, several of which are already regulated and further regulation is estimated to reduce the median number entering over all pathways by approximately 10%. Low temperatures limit the area for establishment but small areas of Spain, Italy and Greece can provide climatic conditions suitable for establishment. If infested imported commodities are distributed across the EU in proportion to consumer population, a few hundreds to a few thousands of individuals would reach NUTS 2 regions within which suitable conditions for establishment exist. Although S. frugiperda is a known migrant, entry directly into the EU from extant populations in sub‐Saharan Africa is judged not feasible. However, if S. frugiperda were to establish in North Africa, in the range of thousands to over two million adults could seasonally migrate into the southern EU. Entry into suitable NUTS2 areas via migration will be greater than via commercial trade but is contingent on the establishment of S. frugiperda in North Africa. The likelihood of entry of the pest via natural dispersal could only be mitigated via control of the pest in Africa. If S. frugiperda were to arrive and become a pest of maize in the EU, Integrated Pest Management (IPM) or broad spectrum insecticides currently used against existing pests could be applied.
Herbivore-induced plant volatiles (HIPV) provide important information that influences host location behaviour for insect natural enemies, such as parasitoid wasps, that develop in the bodies of ...herbivorous insects. The dietary breadth of both the parasitoid and its host may affect the extent to which a searching parasitoid relies on HIPV. Specialist species are expected to rely on specific volatile cues to which they respond innately, whereas generalists are expected to show a higher degree of phenotypic plasticity that depends on foraging experience in the parasitoid. We compared the response to HIPV emitted by different plant species damaged by host and nonhost caterpillars for two congeneric parasitoid species, the specialist Diadegma semiclausum and the generalist Diadegma fenestrale, attacking caterpillars of the diamondback moth, Plutella xylostella. For the three tested plant species, Brassica oleracea, a feral Brassica population and Sinapis alba, both parasitoid species preferred volatiles from host-infested plants over those produced by undamaged plants. However, both parasitoid species only distinguished between volatiles induced by host and nonhosts when the caterpillars had been feeding on B. oleracea, the plant on which they had been reared. Chemical analysis of the volatile blends could not explain volatile preferences of the parasitoids. Despite the difference in their dietary breadth, the two parasitoids responded similarly to HIPV and experience treatments. A flexible response to a wide array of volatile blends by parasitoids is probably important in nature, given that different generations of the host and the parasitoid probably develop on different food plants.
► Parasitoids of herbivorous insects often rely on plant volatiles during foraging. ► The response to volatiles is affected by dietary breadth and experience. ► We show that a generalist and a specialist wasp respond similarly to plant odours. ► We show that the type of experience determines volatile discrimination ability. ► Rearing history and food plant diversity may explain the flexible response to odours.
EFSA was asked to update the 2015 EFSA risk assessment on Xylella fastidiosa for the territory of the EU. In particular, EFSA was asked to focus on potential establishment, short‐ and long‐range ...spread, the length of the asymptomatic period, the impact of X. fastidiosa and an update on risk reduction options. EFSA was asked to take into account the different subspecies and Sequence Types of X. fastidiosa. This was attempted throughout the scientific opinion but several issues with data availability meant that this could only be partially achieved. Models for risk of establishment showed most of the EU territory may be potentially suitable for X. fastidiosa although southern EU is most at risk. Differences in estimated areas of potential establishment were evident among X. fastidiosa subspecies, particularly X. fastidiosa subsp. multiplex which demonstrated areas of potential establishment further north in the EU. The model of establishment could be used to develop targeted surveys by Member States. The asymptomatic period of X. fastidiosa varied significantly for different host and pathogen subspecies combinations, for example from a median of approximately 1 month in ornamental plants and up to 10 months in olive, for pauca. This variable and long asymptomatic period is a considerable limitation to successful detection and control, particularly where surveillance is based on visual inspection. Modelling suggested that local eradication (e.g. within orchards) is possible, providing sampling intensity is sufficient for early detection and effective control measures are implemented swiftly (e.g. within 30 days). Modelling of long‐range spread (e.g. regional scale) demonstrated the important role of long‐range dispersal and the need to better understand this. Reducing buffer zone width in both containment and eradication scenarios increased the area infected. Intensive surveillance for early detection, and consequent plant removal, of new outbreaks is crucial for both successful eradication and containment at the regional scale, in addition to effective vector control. The assessment of impacts indicated that almond and Citrus spp. were at lower impact on yield compared to olive. Although the lowest impact was estimated for grapevine, and the highest for olive, this was based on several assumptions including that the assessment considered only Philaenus spumarius as a vector. If other xylem‐feeding insects act as vectors the impact could be different. Since the Scientific Opinion published in 2015, there are still no risk reduction options that can remove the bacterium from the plant in open field conditions. Short‐ and long‐range spread modelling showed that an early detection and rapid application of phytosanitary measures, consisting among others of plant removal and vector control, are essential to prevent further spread of the pathogen to new areas. Further data collection will allow a reduction in uncertainty and facilitate more tailored and effective control given the intraspecific diversity of X. fastidiosa and wide host range.
Article 42 of the European Regulation (EU) 2016/2031, on the protective measures against pests of plants, introduces the concept of ‘high risk plants, plant products and other objects’ that are ...identified on the basis of a preliminary assessment to be followed by a commodity risk assessment. Following a request of the European Commission, this Guidance was developed to establish the methodology to be followed when performing a commodity risk assessment for high risk commodities (high risk plants, plant products and other objects). The commodity risk assessment performed by EFSA will be based on the information provided by the National Plant Protection Organisations of non‐EU countries requesting a lifting of import prohibition of a high risk commodity. Following international standards on pest risk analysis, this Guidance describes a two‐step approach for the assessment of pest risk associated with a specified commodity. In the first step, pests, associated with the commodity, that require risk mitigation measures are identified. In the second step, the overall efficacy of proposed risk reduction options for each pest is evaluated. A conclusion on the pest‐freedom status of the commodity is achieved. The method requires key uncertainties to be identified.
The trade in plants for planting is a major pathway for the introduction and further spread of alien plants, pests and diseases. Information about the structure of plant trade networks is not ...generally available, but it is valuable for better assessing the potential risks associated with the trade in live plants and the development of prevention and mitigation measures and policy. The discovery of two larvae of Anoplophora chinensis (citrus longhorn beetle – CLB) in 2009, at a nursery importing Acer palmatum from China in one of the major Dutch tree nursery areas, has resulted in the creation of a detailed dataset on the intra-European Union trade in its potential hosts. This study describes European imports of the primary host of Anoplophora chinensis , Acer spp., into the Netherlands (1998-2012) and the effects of the finding in a tree nursery area. In addition, shipments of Acer spp. from 138 producers in the nursery area in 2009 were analysed in a one-off analysis of intra-EU trade. The volume of Acer spp. imports from Asia was stable early during the studied period, and declined to 5% of the initial imports after a period of interceptions, illustrating the effect of regulations. The number of notifications of Anoplophora chinensis infestations in imported consignments of Acer spp. increased sharply in the years up to 2007, then declined as imports also reduced. Although plants were shipped to destinations throughout Europe, each producer shipped plants only to few destinations in few countries. Most of the plants were shipped to nurseries in EU countries. These patterns could make it easier to target these high risk destinations for control measures. The lack of transaction records makes it difficult to trace the destination of plants. More systematic electronic record keeping by traders and growers and the data being collated in a database that can be made available to regulatory authorities, together with further studies of plant trade data using network approaches, would be beneficial for improving trace-back and trace-forward and provide better safeguards for plant health and quality.
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