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The Panel on Plant Health conducted a pest risk assessment for Liriomyza huidobrensis and Liriomyza trifolii in the European Union and identified and evaluated the phytosanitary measures listed in Council Directive 2000/29/EC. Entry on the principal pathways (plants for planting, cut flowers and leafy vegetables) is assessed as likely as the pests are regularly associated with the pathways at origin, survival during transport or storage is high and only partially affected by current pest management procedures, and transfer to a suitable host is likely as their hosts are so widespread. Establishment is rated as very likely because both species have established populations in most countries of the EU, with transient populations occurring outdoors in non-Mediterranean areas. Spread within the EU is considered to be likely because the pests can readily be moved with plant material. The magnitude of the potential consequences is rated as minor for both species in Mediterranean areas. In non-Mediterranean countries it is moderate for both species in protected crops but, outdoors, impacts are minor for L. huidobrensis and minimal for L. trifolii. The current regulations to prevent entry and spread were found to be only partially effective as interceptions are still being made, cut branches with foliage and leafy vegetables other than celery are excluded, and the methods for inspection and the treatments required to confirm pest free areas, places of production and consignments are not clearly specified. Removal of the legislation would have some advantages and disadvantages but may not have a major effect. The regulations could be tightened by including additional commodities, clearly prescribing the inspection procedures and the appropriate treatments to be used and combining these with other measures, e.g. screening. The application of protected zones to areas where the pests are not yet present can be applied to help prevent further spread. © European Food Safety Authority, 2012

The European Food Safety Authority (EFSA) requested the Panel on Plant Health (PLH Panel) to provide guidance for the evaluation of the effectiveness of the options for plants and plant products for reducing the risk of introduction and spread of harmful organisms in the European Union territory. Two operational tools are presented: a checklist for evaluating a proposed risk reduction option (RRO) and a database of references corresponding to published guidance documents or experimental assessments of RROs. The checklist can be used by the Panel or the dossier-submitting parties to verify whether all required information is provided in support of a RRO, to quickly describe information supplied to EFSA and to identify major gaps in the data. Four types of RRO assessments are distinguished in the proposed checklist according to their purposes and characteristics: experimental assessment of the effectiveness of the option to reduce pest infestation in plant material/products under laboratory/controlled conditions; experimental assessment of the effectiveness of the option to reduce pest infestation in plant material/products under operational conditions; analysis of the applicability of the RRO; and assessment of the effectiveness of the option to reduce the risk of pest entry from an infested area to a pest-free area. The database of references is intended to assist the Panel in (i) identifying potential RROs for a given pest and plant material, and (ii) quickly retrieving relevant experimental data and guidance documents for assessing a proposed RRO. In addition, the current document provides recommendations for assessing RROs, specifically: on experimental design; on the use of statistical methods including approaches for studying uncertainty; on the use of quantitative pathway analysis and spread models describing their advantages and limitations; and on recommendations for general surveillance and specific surveys. The European Food Safety Authority (EFSA) requested the Panel on Plant Health (PLH Panel) to provide guidance for the evaluation of the effectiveness of the options for plants and plant products for reducing the risk of introduction and spread of harmful organisms in the European Union territory. Two operational tools are presented: a checklist for evaluating a proposed risk reduction option (RRO) and a database of references corresponding to published guidance documents or experimental assessments of RROs. The checklist can be used by the Panel or the dossier-submitting parties to verify whether all required information is provided in support of a RRO, to quickly describe information supplied to EFSA and to identify major gaps in the data. Four types of RRO assessments are distinguished in the proposed checklist according to their purposes and characteristics: experimental assessment of the effectiveness of the option to reduce pest infestation in plant material/products under laboratory/controlled conditions; experimental assessment of the effectiveness of the option to reduce pest infestation in plant material/products under operational conditions; analysis of the applicability of the RRO; and assessment of the effectiveness of the option to reduce the risk of pest entry from an infested area to a pest-free area. The database of references is intended to assist the Panel in (i) identifying potential RROs for a given pest and plant material, and (ii) quickly retrieving relevant experimental data and guidance documents for assessing a proposed RRO. In addition, the current document provides recommendations for assessing RROs, specifically: on experimental design; on the use of statistical methods including approaches for studying uncertainty; on the use of quantitative pathway analysis and spread models describing their advantages and limitations; and on recommendations for general surveillance and specific surveys.

The European Food Safety Authority (EFSA) requested the Panel on Plant Health to develop a methodology for assessing the environmental risks posed by harmful organisms that may enter, establish and spread in the European Union. To do so, the Panel first reviewed the methods for assessing the environmental risks of plant pests that have previously been used in pest risk assessment. The limitations identified by the review led the Panel to define the new methodology for environmental risk assessment which is described in this guidance document. The guidance is primarily addressed to the EFSA PLH Panel and has been conceived as an enhancement of the relevant parts of the “Guidance on a harmonised framework for pest risk assessment and the identification and evaluation of pest risk management options by EFSA”. Emphasizing the importance of assessing the consequences on both the structural (biodiversity) and the functional (ecosystem services) aspects of the environment, this new approach includes methods for assessing both aspects for the first time in a pest risk assessment scheme. A list of questions has been developed for the assessor to evaluate the consequences for structural biodiversity and for ecosystem services in the current area of invasion and in the risk assessment area. To ensure the consistency and transparency of the assessment, a rating system has also been developed based on a probabilistic approach with an evaluation of the degree of uncertainty. Finally, an overview of the available risk reduction options for pests in natural environments is presented, minimum data requirements are described, and a glossary to support the common understanding of the principles of this opinion is provided.

The Panel on Plant Health was requested by the European Commission to deliver a scientific opinion on the risk posed by the oriental chestnut gall wasp, Dryocosmus kuriphilus to the EU territory and to identify and evaluate risk management options. Additional analyses were conducted by the Panel to a) determine the distribution of the endangered area within the EU territory; b) investigate the pattern and rate of pest diffusion and c) consider the environmental risk of introduction of the biological control agent Torymus sinensis identified as a potential management option. The Panel concluded in its assessment that a) Castanea plants for intended planting represent the main pathway for entry of D. kuriphilus to the EU; b) D. kuriphilus has a very high potential for establishment in the EU and the climate is suitable wherever Castanea sativa is grown in southern, central and western Europe; c) the average rate of spread of D. kuriphilus is estimated as 8 km/yr; d) spread within the EU is likely, due to adult dispersal by flight and the movement of plants containing eggs and larvae which remain undetected within dormant buds; e) the potential effects on fruit yield reduction are considered moderate and the environmental impact in Castanea woodland is considered as low; f) all EU chestnut production is endangered but the areas of fruit production with the highest degree day accumulations where D. kuriphilus is absent, e.g. in northern Portugal, northern Spain and south-west France, are identified as particularly at risk; g) management options to reduce likelihood of introduction and spread consist of certifying Castanea planting material from pest free areas/places of production; h) classical biological control and plant varietal resistance are identified as management options to reduce the magnitude of impact. The Panel on Plant Health was requested by the European Commission to deliver a scientific opinion on the risk posed by the oriental chestnut gall wasp, Dryocosmus kuriphilus to the EU territory and to identify and evaluate risk management options. Additional analyses were conducted by the Panel to a) determine the distribution of the endangered area within the EU territory; b) investigate the pattern and rate of pest diffusion and c) consider the environmental risk of introduction of the biological control agent Torymus sinensis identified as a potential management option. The Panel concluded in its assessment that a) Castanea plants for intended planting represent the main pathway for entry of D. kuriphilus to the EU; b) D. kuriphilus has a very high potential for establishment in the EU and the climate is suitable wherever Castanea sativa is grown in southern, central and western Europe; c) the average rate of spread of D. kuriphilus is estimated as 8 km/yr; d) spread within the EU is likely, due to adult dispersal by flight and the movement of plants containing eggs and larvae which remain undetected within dormant buds; e) the potential effects on fruit yield reduction are considered moderate and the environmental impact in Castanea woodland is considered as low; f) all EU chestnut production is endangered but the areas of fruit production with the highest degree day accumulations where D. kuriphilus is absent, e.g. in northern Portugal, northern Spain and south-west France, are identified as particularly at risk; g) management options to reduce likelihood of introduction and spread consist of certifying Castanea planting material from pest free areas/places of production; h) classical biological control and plant varietal resistance are identified as management options to reduce the magnitude of impact.

The Scientific Panel on Plant Health was requested by EFSA to develop a guidance document on a harmonised framework for risk assessment of organisms harmful to plants and plant products and the identification and evaluation of risk management options. The document provides guiding principles on assessment practices and approaches when assessing risks to plant health to support the decision-making process under Council Directive 2000/29/EC. The framework aims at implementing the fundamental principles of risk assessment as laid down in Regulation (EC) No 178/2002, most importantly the independence and transparency of risk assessments carried out by EFSA. The document discusses the main issues of the pest risk assessment process: terminology, data requirements and data-related uncertainties. Furthermore, the document provides a framework for pest risk assessment and evaluation of pest risk management options. For the assessment of entry, establishment and spread of pests; both qualitative and quantitative approaches are recommended. An EFSA-adapted EPPO scheme is proposed should a qualitative approach be followed. The assessment of potential consequences of pest introduction and spread considers direct and indirect effects on all affected plant species as well as on the environment. The assessment of economic impacts falls outside the remit of EFSA. For the characterization of the overall risk, the use of risk matrices is proposed to combine qualitative scores. Upon request by the risk manager, risk management options may be identified. Potential changes in risk level resulting from different management options may also be assessed. Uncertainty and sensitivity analysis should be performed for the whole assessment process. For transparency reasons, the process of data collection should be recorded and included in the assessment. Principal requirements for the documentation of the pest risk assessment process are also discussed.

A model was developed to describe the effects of temperature and leaf wetness duration in controlled-environment experiments on the development of light leaf spot on oilseed rape (cv. Bristol) leaves inoculated with Pyrenopeziza brassicae conidial suspensions. A Gompertz function was used to describe the progress with time in percentage leaf area with sporulation, and included the parameters maximum percentage leaf area with sporulation (c); maximum rate of increase in percentage leaf area with sporulation (r); and latent period (l, the time from inoculation until the leaf area with sporulation reached 37% of c). The effects of leaf wetness duration on c and r were also described with Gompertz functions, which included the parameters minimum leaf wetness duration (v(c) or v(r)); and maximum of c (m(c)) or maximum of r (m(r)). The effects of temperature on m(c), v(c) and v(r) were described by quadratic functions, and the effect of temperature on m(r) was described by a linear function. The combined model described the progress with time in percentage leaf area with sporulation, including the effects of temperature and leaf wetness duration on the parameters c, r and l. It generally fitted well to the observed data. Latent periods in previously published experiments were predicted accurately by the model, but percentage leaf area with sporulation was not. Assuming a great number of conidia were dispersed and infection occurred when there was 2 mm h(-1) rain for 0.5 h, the model estimates for latent period were used to predict the dates when large increases in light leaf spot severity occurred in experiments at Rothamsted on winter oilseed rape (cv. Bristol) under natural conditions in 1998/99 and 1999/2000. The predictions agreed with the observations.