How can you combat powdery mildew on apple trees?

Hello, my apple tree has powdery mildew. I bought a spray for fruit trees from Raiffeisen, but unfortunately, it didn't help much. Now I've used baking soda, but I don't know how often I need to repeat it. There are conflicting instructions online. Does anyone have any experience? One says daily, another says weekly… I also don't want to dry out the leaves too much, especially since we don't get any rain here at all.