Can you upload some images? How bad is the infection? Control in the home garden is often based around protective sprays of fungicide but if the tree is already infected then obviously this would not be appropriate. Depending on how severe the infection is, you may be able to prune out the infected leaves/branches and protect any new growth with protective sprays. If it's really bad, the tree may not be worth saving. Be sure to remove and destroy any leaves an branches that may have fallen to the ground.