Pest survey card on Elsinoë australis, E. citricola and E. fawcettii

Abstract

This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M-2020-0114), at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for Elsinoë australis, E. citricola and E. fawcettii surveys. These are required to design statistically sound and risk-based pest surveys, in line with current international standards. The fungi E. australis, E. citricola and E. fawcettii are clearly defined taxonomic entities causing scab on citrus. Elsinoë australis, E. citricola and E. fawcettii are Union quarantine pests. The import of citrus plants is prohibited while general requirements are in place for the import of citrus fruit, which are the main pathway for entry of these pests into the EU. Elsinoë australis and E. fawcettii produce ascospores in the leaf litter and conidia on lesions in plant tissues that can be disseminated by rain splash and wind, but dispersal distances are not known. Mild temperatures and wetness are necessary for infection and lesions appear after four to six days. The commercial citrus species most relevant for the EU are susceptible to these three fungi. Due to the wide availability of host species and climatic suitability, all citrus-growing areas in the EU are considered potentially suitable for their establishment. Long-distance spread is likely to occur through the movement of infected plant material. To increase the likelihood of detecting the three fungi, visual examination of symptoms should be preferentially conducted in autumn before the harvest period. Symptoms caused by E. australis, E. citricola and E. fawcettii are non-specific, so visual examination should be followed by molecular tests to identify the pests. Based on the analyses of the information on the pest–host plant system, the various units that are needed to design a survey should be defined and tailored to the situation in each Member State.