I suspect the symptoms could be caused by Apiognomonia eythrostoma, a fungus affecting in our region apricot mainly, but in the last two years also cherry trees. The pathogen overwinter on fallen leaves and ascospores are released with rainfall events in spring after shuck split .
Therefore treatment in autumn with ziram + copper are not effective.
Disease should be controlled in spring using copper before rainfall events or better with dodine .
I would suggest to check for IPM weekly bulletin in your area (Bologna or Modena) to spray in the more correct period, or alternatively call the Plant Protection Service of Emilia-Romagna Region for more informations