Franco, I too was having a problem with squirrels and picked up a couple of things here, not sure if available to you in Italy. I got a yard owl statue, its made of plastic and you put rocks inside to hold it down then another product called "Deer Away", that you spray on the trees, smells mostly like hot chili's this seems to have worked or you could try making a tea of crushed red peppers, steep them in some hot water and then spray your tree only problem with this is you have to do it after every rain and hope the squirrels don't develop a taste for chili's! Check with your garden center to see what they have to help you.
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