What is it?
Black spot, caused by the fungus Diplocarpon rosae, is one of the most common diseases in rose bushes. It is visually identified by dark circular spots on the leaves that expand and cause a yellowish halo around them, eventually leading to leaf drop. This fungus thrives in conditions of high humidity, mild temperatures, and when water remains stagnant on the foliage for several hours, weakening the plant if not controlled.
Treatment plan
Immediate
Foliage cleaning
Remove and discard leaves showing black spots or evident yellowing.
Prevention
Improve watering
Ensure watering is done only at the base of the plant, never on the leaves.
1-3 days
Fungicide application
Use a specific fungicide for roses or a copper-based one.
1 week
Increase ventilation
Lightly prune some inner branches if the foliage is too dense to improve air flow.
Care during recovery
- Watering
- 2 to 3 times per week, directly to soil, avoiding wetting leaves.
- Light
- Full sun, minimum 6 to 8 hours of direct light daily.
- Temperature
- Between 15°C and 25°C; tolerates moderate frost.
- Soil
- Rich in organic matter, deep, and with excellent drainage.
- Fertilizer
- Rose fertilizer every 20 days during the growing season.
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