Pest survey card on regulated viruses and phytoplasmas that infect Prunus species

This pest survey card has been prepared in the context of EFSA´s mandate on plant pest surveillance (M-2020-0114) at the request of the European Commission. Its purpose is to guide EU Member States in gathering information for designing risk-based surveys on regulated viruses and phytoplasmas that infect species of the genus Prunus. These pathogens are Union quarantine pests and occur in various parts of the world. American plum line pattern virus, ‘Candidatus Phytoplasma fraxini’, and ‘Ca. P. ziziphi’ have also been reported from the EU but
have a restricted distribution. All pathogens covered by this survey card are transmitted by vegetative propagation and grafting. Human-assisted spread through the movement of infected plants for planting or grafts is expected to be an important pathway for long-distance spread. In addition, several of these viruses and all regulated phytoplasmas can spread via vectors. The climatic conditions and availability of host plants in the EU are favourable for their establishment. The regulated viruses and phytoplasmas are often known to infect multiple Prunus species, including fruit crops as well as ornamental hosts. Several of these pathogens have a wider host range that may include other cultivated plants and wild host species. Detection surveys should focus on economically relevant hosts. All known host species should be considered in delimiting surveys. It is recommended to conduct surveys by visual examination of Prunus plants. Infected plants may show a variety of symptoms that are not pathogen-specific and overlap with those caused by non-regulated viruses and phytoplasmas. The identification of the regulated viruses in the collected leaf samples requires the application of specific laboratory tests, group tests or
high-throughput sequencing. The regulated phytoplasmas that infect Prunus species can be identified using a generic PCR followed by amplicon sequencing, while specific PCR tests are available to detect ‘Ca. P. phoenicium’.