Leaf Spot on blueberry bushes...

I have two young blueberry pushes planted in large pots and tey have developed leaf spot. I was instructed to use a fungicide such as daconil or liquid copper on the bushes. Since this is a fungus, do I need to take all the infected leaves off, which would be about 1/2 of them? Has anybody ever had this problem and if so, how did you deal with it and were you successful? This is my first attempt at growing blueberry bushes so I'd appreciate any and all help/input. TIA.