Circular spots occur on leaves which results in their shedding from the plant. Use appropriate foliar fungicides to prevent damage. If leaf spots are seen, pick off and destroy the infected leaves or use sprays containing basic copper sulfate. If bacterial leaf spot causes problems, pick off and destroy infected leaves. No chemical control is listed.
Infection is characterized by yellow-orange pustules on the lower leaf surface.
Fungicide control is usually not necessary. Symptoms initially appear as light yellow-orange spots on the upper surface of leaves of the various hosts. Ultimately brown pustules develop beneath these light spots on the underside of leaves. In severe infestations leaves dry and hang down along the stem. Canker can kill branches or entire plants.