⚠ CriticalFiddle Leaf Fig Bacterial Infection — Spreading Brown Spots with Yellow Halos
Commonly affects: Ficus lyrata (Fiddle Leaf Fig)
Small, water-soaked brown spots appear across the leaf surface, each surrounded by a distinct yellow halo. Unlike root-rot spots (which typically start at leaf margins or bases), bacterial spots appear anywhere on the leaf and spread rapidly in humid, warm conditions with poor air circulation. The spots merge to form larger irregular patches. Bacterial leaf spot in Ficus lyrata is caused primarily by Pseudomonas cichorii and enters through wounds or natural leaf openings, spreading via water droplets from watering or misting.
Potential Causes
- 1Overhead watering or frequent misting wetting the foliage and providing the moisture film bacteria need to spread
- 2Poor air circulation allowing moisture to remain on leaf surfaces for extended periods
- 3Introduction via contaminated tools, soil, or infected plant material
- 4Warm temperatures (22-30°C) combined with high humidity creating optimal bacterial growth conditions
Solution Steps
- 1Remove all visibly infected leaves immediately and dispose of them in sealed bags — do not compost.
- 2Sterilise all pruning tools with 70% isopropyl alcohol before and after use.
- 3Apply a copper-based bactericide spray to remaining foliage, covering all surfaces. Repeat every 7-10 days for 3-4 cycles.
- 4Improve air circulation around the plant with a fan running on low nearby.
- 5Switch entirely to substrate-level watering — never water overhead or mist the foliage.
- 6Isolate from other plants until the infection is fully controlled — bacterial leaf spot can spread to other Ficus species.
Prevention Tip
Never mist Fiddle Leaf Figs — despite this being commonly recommended, wet foliage dramatically increases bacterial leaf spot risk. Humidity should be raised with a humidifier rather than misting.
