Black Marks on Phalaenopsis Flowers: Fungus, Sooty Mold, or Aging?

South Florida Outdoor Phalaenopsis Issue

Two oldest Phalaenopsis in slatted baskets, eastern exposure, in bloom. Petal edges show black water-mark spots. Otherwise healthy: new leaves, good roots.

Likely Causes (Not Virus)

1. Botrytis / fungal spotting: Buds got wet before/during opening.
2. Natural senescence: Older flowers develop spots near end of life.
3. Sooty mold: Wipes off with alcohol/Q-tip → cosmetic, not lethal.

Paphiopedilum in Dirt—Leave It

First Paph in bud, potted in soil in plastic pot. Don't repot yet. Keep soil barely moist. After bloom, repot in fine fir bark + perlite.

Action Items

• Test black spots with alcohol—if removable, sooty mold.
• Keep water off flowers/buds (water at base, morning only).
• Monitor leaves—if spots appear there, apply fungicide.
• Enjoy the bloom; repot Phals after flowering if mix is old.