Intensive preventative sprays
Often experienced users here tout infrequent sprays, but I have found doing preventative sprays on all my fruits has worked rather well. I have never seen a fungus on my blueberries or brambles. Once you get it, it's a matter of control. I never got it thanks to a very intensive spray schedule. All you have to do is check your local university to see what fungal problems are in your area. Waiting till you get them is a huge mistake IMHO. As at best you have to control, it's there now, and never going away. In my case, it could not establish anywhere, so spore counts are extremely low.
I'm not advocating unnecessary sprays, they are needed according to MSU in my case. Some of the advice to wait and see what problems may or may not happen is bad advice. It's easy enough to find out what is in your area without waiting for infections.