Plant Problem Diagnosis Key / Diseases
Disease
Black spot of rose
Diplocarpon rosae
The main leaf disease of roses. Spores spread by splashing water and need about seven hours of wet leaf to infect.
Signs
- Round black spots with feathery, fringed edges on the upper surface.
- Leaves yellow around the spots and drop, starting low on the plant.
- Raised purple-red blotches on first-year canes.
What favors it
Leaves wet for about seven hours or more; overhead watering and rainy springs.
Prevention
- Plant disease-resistant roses.
- Water at the base in the morning.
- Prune to improve air circulation; clear fallen leaves in fall and spring.
Crops it shows up on
Roses & ornamentals.
Often confused with
Sources
- Black Spot Disease of RosesUniversity of Maryland Extension
- Rose DiseasesClemson Cooperative Extension (HGIC)
- Black SpotUC Statewide IPM Program
Treatment by crop
Cultural, biological and chemical options in the order to use them, and notes written for each crop.
Identification is free. Treatment is on the Home and Pro plans.
Questions in the key that lead here
- Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
No, only damage or discoloration - Where is the problem?
Leaves - What does the leaf damage look like?
Distinct spots or lesions - Where on the plant are the spots?
Older, lower leaves first, moving up - What do the spots look like?
Black spots with feathered edges on rose leaves
Not a match? Start the key or describe what you see.
More photos
More from university Extension: search Extension pages on black spot of rose, or find a plant diagnostic lab through your state's Extension.
Other diseases
- Anthracnose
- Apple scab
- Bacterial leaf scorch
- Bacterial leaf spot
- Bacterial wetwood (slime flux)
- Bacterial wilt of cucurbits
- Black knot
- Bleeding canker
- Boxwood blight
- Canker diseases
- Cedar-apple and related rusts
- Crown gall
- Damping-off
- Downy mildew
- Dutch elm disease
- Early blight and Alternaria leaf spot
- Elm yellows (phloem necrosis)
- Fire blight
- Fusarium wilt
- Gray mold (Botrytis)
- Late blight
- Mosaic viruses
- Needle cast and tip blight
- Oak wilt
- Powdery mildew
- Root and butt rot
- Root rot (Pythium and Phytophthora)
- Rust
- Septoria leaf spot
- Shade tree anthracnose
- Sooty mold
- Tar spot of maple
- Tomato spotted wilt and impatiens necrotic spot viruses
- Verticillium wilt
- White mold (Sclerotinia)
- White pine blister rust