Tomato ringspot virus detected in Punica granatum in Italy
The NPPO of Italy recently informed the EPPO Secretariat of the detection of Tomato ringspot virus (Nepovirus, ToRSV - EPPO A2 List) in Punica granatum (pomegranate) trees. In 2012, the University of Bologna had imported cuttings of 126 cultivars of P. granatum for fruit production and ornamental purposes from the USDA/ARS clonal germplasm repository of Davis (California, US). This planting material was introduced in accordance with 2008/61/EC Directive, although the latter does not include specific requirements for pomegranate pests. Rooted cuttings were planted in January 2013 in an experimental field located near Ravenna (Emilia-Romagna region) under post-entry quarantine. During the first inspection in spring 2013, no symptoms were observed but samples were collected and tested for the presence of several viruses. In autumn 2014, the presence of an unspecified nepovirus was detected. In May 2015, further analysis (serological tests, RT-PCR, sequencing) confirmed the presence of ToRSV. However, before these final results were obtained, plants for planting originating from the experimental field in Ravenna had been given to 5 other farms located in Emilia-Romagna, as well as to the University of Bari (Puglia region) and to a nursery in Lazio region. ToRSV was detected in these 5 farms in Emilia-Romagna. It is also noted that when the presence of ToRSV was finally confirmed, some of the initially asymptomatic plants had started to show ringspot symptoms on the leaves. Official phytosanitary measures will be taken to eradicate the disease. All pomegranate plants of US origin will be uprooted and destroyed. As the nematode vector, Xiphinema americanum sensu lato is not known to occur in Italy, natural spread (if any) is considered to be limited. In 2015, surveys will be carried out within a radius of 500 m around infected sites, as well as in nurseries located within a radius of 1 km around infected sites, in particular to verify the health status of P. granatum plants that are sold to growers and gardeners.
The pest status of Tomato ringspot virus in Italy is officially declared as: Transient, actionable, under eradication.
Note: According to EPPO Global Database, the presence of ToRSV had been reported in Italy in the 1980s (Canova & Betti, 1983 – Poggi Pollini & Giunchedi, 1984). The Italian NPPO reviewed these publications and explained that the publication from Canova & Betti (1983) referred only to symptoms resembling those of ToRSV on tomato crops in the Po valley and Sardinia, but that the presence of the virus had never been confirmed by laboratory analysis. Therefore this record is now considered unreliable. The second publication (Poggi Pollini & Giunchedi, 1984) presented the results of a survey carried out in 1981 on viruses and virus-like organisms of Rubus spp. In this study, ToRSV was detected in an asymptomatic raspberry plant (Rubus idaeus cv. ‘Milton’) grown in an experimental plot in the province of Trento and which had probably been imported from abroad. Since then, no other records of ToRSV have been made from Italy, suggesting that the virus did not establish.
Sources
NPPO of Italy (2015-10).