When the experienced Rose grower observes orange-yellow spots on the leaves of his plants in early summer he knows that he sees the advance guard of the fungoid disease known variously as orange fungus and red rust.
Some suppose these to be separate diseases; on the contrary they are separate stages in the triune life-cycle of one disease, Phragmidium subcorticatum. The first, or aecidium, stage, gives the orange fungus; the second, or Uredo stage, gives the red rust; the third, or Teleuto stage, gives a black rust.
Where the orange fungus has obtained a strong hold, and has caused trouble for several successive years, it cannot be exterminated at a single attempt. Repeated attacks on it must be made. Measures may begin by spraying the bushes thoroughly in spring before growth starts with Bordeaux Mixture. When the first signs of the disease appear in summer spray with Carbarn, repeating if necessary. The solution should reach the under as well as the upper side of the leaves.
Any leaves that contain signs of black rust should be burned in autumn.