One way to break the cycle is to make certain that apples and junipers are planted far apart. (In urban and suburban settings, this may be less practical, because you can’t control what your neighbors plant.) Another control is to remove the brownish-green balls from your juniper during their first year, before they develop their orange spore horns. On apples, the disease shows up as orange spots on leaves and fruit. Again, the tree is not permanently damaged, but the fruit can be seriously disfigured.
