Cattleya Alliance Black Leaf Spots: Sunburn vs. Fungus, Physan Soak Protocol

Diagnosis: Likely Sunburn, But Treat for Fungus Too

Black oval areas on leaves, not penetrating, with dotted underside = classic sunburn on Cattleya 'Mari's Magic'. But fungal secondary infection possible.

Recommended Protocol

1. Cut leaves below damaged areas (sterile tool).
2. Physan 20 drench: 1 tsp/gal, soak plant 10-15 min.
3. Dry completely before repotting.
4. Repot in fresh bark mix (fine-medium grade).
5. Seal cuts with cinnamon or Rootone.

Physan 20 Strength & Time

1 teaspoon per gallon, 10-15 minute soak. Wear gloves. Ventilate.

Prevention

• Acclimate to higher light slowly (2-3 weeks).
• Morning water only.
• Air movement.
• Consult local orchid society—hands-on diagnosis beats remote.