I did spray lime sulphur twice during winter: The first at leaf fall, the next at leaf budding. But I suppose that didn't work that well for me. The tree already had some signs of fungus last year, albeit not as strong as this year's, but as we entered summer and temperature went up it all was gone. So I'm no sure what to do at the moment. I believe the problem is that my spring is typically very wet which is conducive of fungus attacks. I'm considering getting a place that protects the tree from the rain, but I have yet to find a solution that is aesthetically pleasing. In the meanwhile I will spray with copper oxychloride and use sulphur powder in between. I also thought about completely defoliating the tree and spray abundantly but I think I should wait a little bit longer until leaves harden a bit more and air temperature raises steadily above 15C.