Mock Orange
Symptom Cause  
Leaves curl/discolor; honeydew on undersides of leaves, sooty mold forms
Some leaves turn pale green to yellow; new leaves yellow; plant stunted
Iron Deficiency
Leaves coated with white powder
Powdery Mildew
Leaf edges brown, black, die;
Salt Damage
Black powdery sooty mold fungus forms on honeydew;
Sooty Mold