MINIREVIEW ECONOMIC SIGNIFICANCE AND CONTROL OF BACTERIAL SPOT/CANKER OF STONE FRUITS CAUSED BY XANTHOMONAS ARBORICOLA pv. PRUNI

Bacterial spot and canker of stone fruits is a multifaceted disease caused by Xanthomonas arboricola pv. pruni. The disease has a more significant economic impact on Japanese plums, peach and nectarines. Estimated crop losses can reach over 10,000 €/ha in epidemic years in modern commercial plum orchards. Disease establishment and pattern of the epidemics are strongly influenced by prevailing climatic conditions and by the species and/or cultivar of the host plant. European plums and almond are quite tolerant to the disease, but Japanese plums, peaches, and nectarines are quite sensitive. Sources of resistance are not known for peach and, in general, disease control is based on orchard hygiene and regular sprays with different copper compounds, such as sulphates, oxychlorides and hydroxides, the choice of the copper chemical formulation depending on the phenological phase of the host plant. Alternative control strategies are being developed using bacterial antagonists and possible resistance inducers such as copper glucohumates. Since the disease is strongly influenced by climatic conditions, there is the need to develop a reliable disease forecasting model.