Humidity on pothos
What's Happening
Bacterial infections (Xanthomonas, Pseudomonas) present as water-soaked, translucent lesions that may ooze yellow-brown bacterial exudate, often angular and bounded by leaf veins. Fungal infections (Phyllosticta, Cercospora) show as dry, dark brown to black spots with defined margins and possible concentric rings. Bacterial spots spread rapidly in high humidity; fungal spots progress slower and may produce visible spore structures.
How to Fix It
- 1
Examine lesion characteristics: water-soaked/translucent with ooze = bacterial; dry/dark with rings = fungal
- 2
For bacterial: apply copper bactericide every 7-10 days; remove severely affected leaves; improve air circulation immediately
- 3
For fungal: apply systemic fungicide (propiconazole) following label; remove infected tissue; allow soil to dry between waterings
- 4
Isolate plant immediately upon diagnosis; bacterial infections spread 3x faster than fungal via water splash
- 5
Sterilize all tools with 70% isopropyl between plants; bacterial cross-contamination risk is higher than fungal
How to Prevent It
Maintain 40-60% humidity (not higher) with active air circulation to prevent bacterial proliferation. Use copper-based preventive sprays monthly during high-humidity months. Water at soil level only; avoid overhead watering. Inspect new plants thoroughly before adding to collection; bacterial infections often originate from nursery stock.
Related Problems
Same Problem on Other Plants
Go Deeper
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