Monitoring of Pepino Mosaic Virus (PepMV) in the Maltese Islands

Abstract

A survey was carried out on greenhouse tomato crops with the aim of determining if Pepino Mosaic Virus (PepMV) has been introduced in the Maltese Islands. This virus is an important highly infectious new viral pathogen infecting greenhouse tomato crops in Europe, and for this reason, it has been included in the European Plant Protection Organisation (EPPO) Alert List. PepMV belongs to the genus potexvirus. This virus has a narrow host range mainly limited to Solanaceae. There are no known arthropods or fungal vectors as the virus is reported to spread rapidly by mechanical means. The damage caused by PepMV in tomato is always high, which can result in unmarketable fruits and a reduction of 15% yield in infected tomato plants. PepMV symptoms were never reported in Malta, however, specific quarantine controls were made trying to keep the Maltese Islands free from this virus. PepMV surveys have been carried out by the Plant Biotechnology Centre within the Plant Health Department for the past 3 years. A total of 40 different greenhouses spread around Malta and Gozo were visited from which 342 leaf samples corresponding to 1,710 tomato plants were collected. Moreover 27 samples of imported tomato products including seeds, seedlings and tomato fruits were taken from various local suppliers. The survey was based on field surveys, Double Antibody Sandwich - Enzyme Linked Immunosorbent Assay (DAS-ELISA) and biological indexing by mechanical transmission on herbaceous hosts. All the tests were carried out at the Plant Biotechnology Centre, Plant Health Department within the Ministry for Rural Affairs and the Environment. For the 3rd consecutive year it showed that Malta is free from PepMV, however necessary precautions must continue in order to keep this disease at bay.