Scientific Opinion on the pest categorisation of Cherry leafroll virus
The Panel on Plant Health performed a pest categorisation of Cherry leafroll virus (CLRV) for the European Union (EU) territory. CLRV is a well-defined virus species of the genus Nepovirus, for which the entire genome sequence and molecular detection assays are available. CLRV is transmitted by vegetative multiplication of infected hosts and is also seed- and pollen-transmitted (both horizontally and vertically) in many of its hosts. There is, however, evidence that interspecific transmission by the pollen-mediated mechanism is very limited. CLRV has a wide host range, which contains both woody and herbaceous hosts, many of which are largely present in natural environments. It is listed on plants of Rubus spp. for planting in Annex IIAI of Directive 2000/29/EC. CLRV is widely present in the EU but there are very few records on its regulated hosts. It is not expected to be affected by ecoclimatic conditions wherever its hosts are present and has the potential to establish in large parts of the EU territory. CLRV can spread through efficient seed- and pollen-mediated transmission mechanisms and through the movement of vegetatively propagated plants for planting of numerous hosts. However, the existence of efficient and widely adopted certification systems for some of these hosts constitutes a limitation to CLRV spread. Although the virus alone or when in mixed infection can cause significant disease in some hosts, the actual impact of CLRV is very difficult to evaluate but generally appears to be limited.