Detection of Cherry Leaf Roll Virus in intensively managed grafted English (Persian) walnut trees in Italy

Blackline disease, caused by Cherry leaf roll virus (CLRV), is considered a serious threat limiting English walnut (Juglans regia L.) production in Italy and the EU if walnut species other than J. regia are used as rootstock. In spring 2014, canopy decline or death of several walnut trees associated with presence of a necrotic strip at the rootstock-scion junction was observed on plants grafted onto ‘Paradox' (J. hindsii × J. regia) in a commercial orchard located in the Veneto region (north-eastern Italy). To ascertain the presence of CLRV in this orchard and in other walnut intensively managed orchards located in the same region, a monitoring was carried out in 2014- 2015.