Cedar rusts commonly occur in species such as crab apple and hawthorn and several hardwood species. Cedar rust is characterized by yellow spots on the leaf's top surface. On closer inspection, you may notice small bumps with powdery spores. You are likely to notice this disease in mid to late August.
Cedar rust results in early defoliation. The fungi that cause rust will need a second host in its lifecycle. This disease is manageable with fungicide application during bud break or when the spores develop on junipers. You can also prune out rust galls on junipers when you notice them.
Armillaria Root Rot
Armillaria root rot attacks both softwood and hardwood species. One of the common signs of armillaria is browning needles and yellow leaves. The result of this disease is softening of wood that eventually becomes white and dies. In case the tree does not die, it significantly weakens and is predisposed to attacks by other diseases and even insects.
To control armillaria, cut out and burn diseased parts and paint the cuts with plastic paint. Leave the roots and crown uncovered, and avoid soil replacement during cultivation, as this exposure to air kills armillaria.