Pest categorisation of potato virus S (non‐EU isolates)

Abstract

Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus S (PVS). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact compared to the current situation in the EU, and availability of control measures of non-EU isolates of PVS has been evaluated with regard to the criteria to qualify as potential Union quarantine pest. Because non-EU isolates of PVS are absent from the EU, they do not meet one of the requirements to be regulated as an RNQP (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. Populations of PVS can be subdivided into two strains: the ordinary strain (PVS-O) with a worldwide distribution (including the EU), and the Andean strain (PVS-A) which is absent from the EU or considered to have at most a limited distribution in the EU. Two additional divergent isolates (PVS-A/PVS-O recombinants and PVS-arracacha) have also been categorised. Non-EU isolates of PVS-A are expected to have an additional impact as compared to the PVS isolates currently present in the EU, and therefore meet all the criteria to qualify as potential Union quarantine pests; the magnitude of the additional impact is, however, unknown. Non-EU isolates of PVS-A/PVS-O recombinants and of PVS-arracacha also meet these criteria, with the exception of the criterion regarding the potential additional consequences in the EU territory for which the Panel was unable to conclude. Non-EU PVS-O isolates are not expected to have an additional impact in the EU as compared to EU isolates and therefore do not meet the corresponding criterion.

Plant viruses in the system of seed potato production

“…The transmission through contact from infected plants to healthy ones can happen when plants are already damaged by agricultural machinery. The mechanical transmission of PVM and PVA is not always possible presumably due to a low concertation of viruses in plant tissues [17][18][19][20][21]. To prevent plant viruses from spreading in field conditions, it is necessary to have reliable data on the species composition of plant reservoirs of viral infection, the total activity of insect vectors, and possible ways of virus transmission in the particular territory of seed material production.…”