The sharka disease on stone fruits in Italy: a review, with a focus on Tuscany

Abstract

Sharka, caused by plum pox virus (PPV), is by far the most harmful disease of stone fruits (genus Prunus). Although Italy is a major producer of stone fruits, and sharka has spread in most Italian regions since its first identification in the 1970s, information on the diffusion of the disease in Italy results still scattered and incomplete. To address this knowledge gap, the present review aimed to firstly provide a historical overview of sharka in Italy, summarizing outcomes on the disease achieved since the first identification of its causal agent PPV. Data retrieved from a variety of sources (i.e., published literature, official reports and personal communications) showed that (i) sharka spread across almost the whole Italian peninsula as only Liguria, Umbria and Aosta Valley regions officially result disease-free; (ii) the regions with higher rates of infected districts are not always those more dedicated to the production of stone fruits; (iii) only the three major PPV strains causing sharka, i.e., PPV-Dideron (D), PPV-Marcus (M), and PPV-Recombinant (Rec), have been reported in Italy; and (iv) only apricot, peach and plum (i.e., widespread and economically relevant species) are hosts of PPV, with different scenarios among regions. A focus on Tuscany (Central Italy) showed that, (i) sharka has been reported since the 1990s, but extensive PPV monitoring campaigns were run from 2013 to 2021, especially in nurseries; (ii) higher number of symptomatic and PPV positive samples were recorded in farms, mostly in the Arezzo and Florence districts; and (iii) only PPV-M and PPV-Rec strains seem still present. We believe that the present overview will benefit and encourage both researchers for future investigations on sharka and farmers that have to manage the disease.