ROSE DISEASES Bacterial leaf spot causes dark brown sunken spots on the leaf and flower stalks. The flower buds die without
opening. The disease is worse in spring. Cut out and destroy infected plant parts. No chemical control is listed.
Crown gall causes formation of roundish galls with irregular rough surfaces. Galls above ground level should be pruned off and destroyed. Galls on the plant crown are not easily pruned off so destroy the whole plant. Avoid infested soil. No chemical control is listed.
Rose anthracnose causes purplish brown, circular, one- half inch leaf spots. The center of the spot turns gray and drops out. Black spot sprays generally control this disease.
Black spot causes black spots on the leaves. The leaves turn yellow and drop. Remove and destroy fallen infected leaves. Use Funginex, sulfur, chlorothalonil or basic copper sulfate to control this disease.
Botrytis blight causes flower buds to turn brown and decay. The petals of unopened flower buds are easily lifted off the stem. Control this problem with chlorothalonil or benomyl. Remove old flowers as they fade.
Powdery mildew causes upward curling of young leaves and makes a white, powdery coating on the leaves. Use benomyl, Funginex or sulfur to control the disease.
Brand canker develops while plants are under winter protection. Infected roses have a black sooty appearance when uncovered in the spring. This disease is sporadic and does not directly affect the blossoms or leaves. Destroy infected canes. No chemical control is listed.
Brown canker causes cankers with light chestnut brown centers and deep purple margins. Small flecks and purple spots form on the leaves. This disease attacks canes while the roses are under winter protection. Brown canker may be worse on bushes hilled with soil. No chemical control is listed.
Common stem canker gains entrance through a wound. Young cankers are pale yellowish or reddish, becoming brown, sunken and cracked. Destroy cankered canes. Black spot sprays usually prevent new infections.
Dieback, cane blight canker causes leaves on the cane above the canker to wilt, turn brown and die. Destroy the cankered canes. Sprays for black spot may prevent new infections.
Rust causes orange colored spots on the leaves and stems. Clean up infected leaves at the end of the season. Sprays of sulfur or Funginex will control this problem.
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|Crown gall on rose - 62K||Rose canker - 45K|