Suchergebnisse

Trabajo presentado en la 2nd European conference on Xylella fastidiosa (how research can support solutions), celebrada en Ajaccio el 29 y 30 de octubre de 2019. ; Understanding the dispersal of Xylella fastidiosais essential for effective management of the disease. In Puglia, Italy, surveillance is focused on buffer and containment zones, which have been established at the edge of the infected region with the aim of containing further spread. Success of this strategy will strongly depend on whether these zones are wide enough to form a barrier to long-distance dispersal of the bacterium. In this presentation, I will describe our progress towards estimating the dispersal range of Xylellain Puglia using a generic spatial epidemiological model adapted to the biology of the pathosystem. The model simulates the spread of the disease across a heterogeneous landscape depending on the location and timing of introduction, the distribution of host plants, the rate of infection growth in infected olive groves and both short-and long-distance dispersal. Long-distance dispersal seems to be a crucial feature of the Xylellaepidemic, causing rapid spread of the disease over large areas but in an unpredictable manner. To try to estimate long-distance dispersal, we use Approximate Bayesian Computation to calibrate the epidemiological model to observed detections in surveillance monitoring data from 2013 to 2018. I will present resultsfrom the model calibration, comparing long-distance dispersal estimates from models specified for different long-range dispersal mechanisms. This will inform discussion on the roles of mechanisms such as vehicle transport and wind dispersal in spreading Xylellaat regional scales. ; European Union Horizon 2020 grant agreement number 727987. ; Peer reviewed

Trabajo presentado en la 3rd European Conference on Xylella fastidiosa (Building knowledge, protecting plant health), celebrada online el 29 y 30 de abril de 2021. ; Understanding the dispersal of Xylella fastidiosa is essential for effective management of the disease. In Puglia, Italy, surveillance is focused on buffer and containment zones established at the edge of the infected region with the aim of containing further spread. Success of this strategy will strongly depend on whether these zones are wide enough to form a barrier to long distance dispersal of the bacterium. In this presentation, I will describe our progress towards estimating the dispersal range of Xylella in Puglia using a generic spatial epidemiological model adapted to the biology of the pathosystem. The model simulates the spread of the disease across a heterogeneous landscape depending on the location and timing of introduction, the distribution of host plants, the rate of infection growth in infected olive groves and both short and long distance dispersal. Long distance dispersal seems to be a crucial feature of the Xylella epidemic, causing rapid spread of the disease over large areas but in an unpredictable manner. To calibrate the model, we used Approximate Bayesian Computation to compare model simulations to Xylella surveillance data and remote sensing of severe damage. This allows us to contrast a simple spread scenario with more complex scenarios such as anisotropic dispersal in the direction of prevailing winds and spatial variation in disease transmission. In doing so we characterise the spread and estimate the year of introduction. Finally, I will discuss potential for using the model to simulate management strategies and new outbreaks in other regions, using the UK as a case study ; Support from XF-Actors & CURE-XF (EU H2020), EFSA, BRIGIT (BBSRC, Defra & Scottish Government) & Scottish Plant Health Centre.

The European Commission requested EFSA to facilitate the Member States in the planning and execution of their survey activities. In particular, EFSA is asked to provide scientific and technical guidelines in the context of the new plant health regime (Regulation (EU) 2016/2031), in which prevention and risk targeting are given an extra focus, and the European Commission co‐financing programme of the annual Member State survey activities for pests of EU relevance (Regulation (EU) No 652/2014). In order to address this mandate EFSA is requested to deliver by the end of 2019: (i) 47 pest survey cards that contain practical information required for preparing survey design; (ii) survey guidelines for 3 different pests that will be case studies to be developed in collaboration with the EU Member States; and, (iii) support to the Member States on the underpinning statistical methods and use of the EFSA WEB‐based tools RiBESS+ and SAMPELATOR to inform sampling strategy design, including sample size calculations. This technical report describes the methodological approach and the work‐plan EFSA will implement to deliver the requested outputs.

The early detection of Xylella fastidiosa (Xf) infections is critical to the management of this dangerous plan pathogen across the world. Recent studies with remote sensing (RS) sensors at different scales have shown that Xf-infected olive trees have distinct spectral features in the visible and infrared regions (VNIR). However, further work is needed to integrate remote sensing in the management of plant disease epidemics. Here, we research how the spectral changes picked up by different sets of RS plant traits (i.e., pigments, structural or leaf protein content), can help capture the spatial dynamics of Xf spread. We coupled a spatial spread model with the probability of Xf-infection predicted by a RS-driven support vector machine (RS-SVM) model. Furthermore, we analyzed which RS plant traits contribute most to the output of the prediction models. For that, in almond orchards affected by Xf (n = 1426 trees), we conducted a field campaign simultaneously with an airborne campaign to collect high-resolution thermal images and hyperspectral images in the visible-near-infrared (VNIR, 400–850 nm) and short-wave infrared regions (SWIR, 950–1700 nm). The best performing RS-SVM model (OA = 75%; kappa = 0.50) included as predictors leaf protein content, nitrogen indices (NIs), fluorescence and a thermal indicator (Tc), alongside pigments and structural parameters. Leaf protein content together with NIs contributed 28% to the explanatory power of the model, followed by chlorophyll (22%), structural parameters (LAI and LIDFa), and chlorophyll indicators of photosynthetic efficiency. Coupling the RS model with an epidemic spread model increased the accuracy (OA = 80%; kappa = 0.48). In the almond trees where the presence of Xf was assayed by qPCR (n = 318 trees), the combined RS-spread model yielded an OA of 71% and kappa = 0.33, which is higher than the RS-only model and visual inspections (both OA = 64–65% and kappa = 0.26–31). Our work demonstrates how combining spatial epidemiological models and remote sensing can lead to highly accurate predictions of plant disease spatial distribution. ; Data collection was partially supported by the European Union's Horizon 2020 research and innovation program through grant agreements POnTE (635646) and XF-ACTORS (727987). R. Calderón was supported by a post-doctoral research fellowship from the Alfonso Martin Escudero Foundation (Spain).

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

The Panel on Plant Health performed a pest categorisation of non-EU Acleris spp. Acleris is a welldefined insect genus in the family Tortricidae (Insecta: Lepidoptera). Species can be identified using taxonomic keys based on adult morphology and genitalia. The genus includes 261 species attacking conifers and non-conifer plants in many areas in the world, among which 40 species are present in the EU. The non-EU species are collectively listed in Annex IAI of Council Directive 2000/29/EC as Acleris spp. (non-European). Some species are important defoliators in North America, mainly on conifers but also on several broadleaf trees. Females lay eggs on the leaves or on the bark. The larvae bind together with silk the leaves upon which they feed. Pupation occurs in leaves attached with silk or in the soil. Some species are univoltine; others are bivoltine or multivoltine. Flight capacity is not documented, but outbreak expansion suggests that the adults can probably fly long distances. The main pathways for entry are host plants for planting with or without soil, cut branches, fruits of host plants (including cones), round wood with bark and bark. The presence of host plants and suitable EU climate would allow the establishment of the known non-EU harmful species. In the literature, nine non-EU Acleris species are reported as pests on various host plants, namely A. gloverana, A. variana, A. minuta, A. nishidai, A. issikii, A. semipurpurana, A. robinsoniana, A. senescens and A. nivisellana. These non-EU Acleris spp. satisfy all the criteria to be considered as Union quarantine pests. Concerning the other 212 non-EU Acleris species, there is scarce information on host plants, pests status and climatic suitability. Measures are in place to prevent the introduction of non-EU Acleris spp. through the pathways described in the document. As non-EU Acleris spp. are not present in the EU and plants for planting are not the major pathway for spread, non-EU Acleris spp. do not meet the criteria to be considered as regulated non-quarantine pests.