On the contrary plants resulted as symptomatic in spring 2015were not characterized by any signal of stress during the previousseason and showed a growth vigor exceeding the average. In thiscase another predisposing factor for the pathogen has to be takeninto consideration; this is the occurrence of frost events, mainlythose occurring during spring and especially affecting vigorousplants for which tissue hardening and vegetative rest are delayedduring autumn. As showed for other fruit crops (Scortichini, 2010;Ferrante and Scortichini, 2014), spring frosts are very conducive forP. syringae multiplication within the plant