Pest categorisation of Witches' broom disease of lime (Citrus aurantifolia) phytoplasma

Jeger, Michael [Centre for Environmental Policy, Imperial College London] Bragard, Claude [UCL] Candresse, Thierry [Institut National de la Recerche Agronomique (INRA). Plant virus Team] Chatzivassiliou, Elisavet [Agricultural University of Athens, Department of Crop Science, Plant Pathology Laboratory] Dehnen‐Schmutz, Katharina [Coventry University, UK, Centre for Agroecology, Water and Resilience (CAWR)] Gilioli, Gianni [University of Brescia, Medical School, Department of Molecular and Transitional Medicine] Gregoire, Jean‐Claude [Université Libre de Bruxelles, Interfaculty School of Bioengineers] Jaques Miret, Josep Anton [IOBC-WPRS] MacLeod, Alan [Department for environment food and rural affairs (Defra), Chief Plant Health Officer’s Unit] Navarro, Maria Navajas [Institut National de la Recherche Agronomique (INRA)] Niere, Björn [Julius Kühn-Institut, Institute for Plant Protection in Field Crops and Grassland] Parnell, Stephen [University of Salford, Mancheste] Potting, Roel [Netherlands Food and Consumer Product Safety Authority. Office for Risk Assessment and Research] Rafoss, Trond [Bioforsk - Norwegian Institute for Agricultural and Environmental Research. Plant Health and Plant Protection Division] Rossi, Vittorio [Università Cattolica del Sacro Cuore, Facoltà di scienze agrarie, alimentari e ambientali, Department of Sustainable Crop Production] Urek, Gregor [Agricultural institute of Slovenia - Kmetijski inštitut Slovenije, Ljubljana, Slovenia] Van Bruggen, Ariena [University of Florida] Van der Werf, Wopke [Wageningen University. Department of Plant Sciences, Centre for Crop Systems Analysis] West, Jonathan [Rothamsted Research, Department of Plant Biology and Crop Science] Winter, Stephan [Plant Virus Department, German Collection of Microorganisms and Cell Cultures, DSMZ GmbH] Dickinson, Matthew [University of Nottingham] Marzachi, Cristina [Italian National Research Council | CNR · Istituto per la Protezione Sostenibile delle Piante IPSP] Hollo, Gabor [European Food Safety Authority (EFSA)] Caffier, David [High Council for biotechnology] et al.[show all]

The EFSA Panel on Plant Health performed a pest categorisation for the Witches’ broom disease of lime (Citrus aurantifolia) phytoplasma for the EU territory. The pest has been reported in a few countries in the Middle East and is not known to occur in the EU. The disease is caused by a well-defined phytoplasma strain in the ‘Candidatus Phytoplasma aurantifolia’ species, for which efficient molecular detection assays are available. The most important known natural host is Citrus aurantifolia, which is only grown for ornamental purposes in the EU. Sweet limes, rough lemon and trifoliate orange are also naturally infected by that phytoplasma. The latter can be transmitted by grafting also to some citrus species. Other citrus species were reported to be resistant; however, their susceptibility has been assessed only by symptom observations, and the possible presence of phytoplasmas in symptomless plants cannot be ruled out. The phytoplasma is transmitted by the leafhopper Hishimonus phycitis, which is not known to occur in the EU. There is no information on the vector status of other phloem feeding insects of citrus present in the EU. The pest is listed in Annex IIAI of Directive 2000/29/EC. The main pathways for entry, plants for planting and the vector insect, are closed by existing legislation on import of citrus plants. Nevertheless, should the pest enter, it could establish and spread. In countries where Witches’ broom disease of lime (WBDL) is present, it has significant impact. The main knowledge gaps concern (1) and vertical transmission of the phytoplasma to H. phycitis eggs (2) lack of information regarding susceptibility of citrus crops grown in the EU (3) status of potential insect vectors in the EU. Therefore, the WBDL phytoplasma meets the criteria assessed by EFSA for consideration as a potential Union quarantine pest.