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Common Phalaenopsis Orchid Problems: Identification, Treatment, and Prevention

Phalaenopsis orchids are the hardiest of the genus—but even moth orchids face issues. Early recognition and targeted action save plants. Here's a diagnostic guide to the most frequent problems.

Root Rot

#1 killer. Causes: overwatering, poor drainage, media breakdown. Roots turn brown/black, mushy, hollow. Leaves yellow, limp.

Fix: Unpot. Trim all dead roots. Repot in fresh, airy media. Water sparingly until new roots emerge.
Prevent: Water only when media nearly dry. Morning watering. Ensure drainage. Repot every 1–2 years.

Bacterial Leaf Rot

Soft, water-soaked brown spots spreading rapidly. Favored by cool temps + high humidity.

Fix: Cut out infected tissue (sterile tool). Apply bactericide (copper-based or streptomycin). Isolate plant.
Prevent: Avoid water on leaves. Good air flow. Warm nights.

Crown Rot

Discoloration at leaf base (crown). Fatal if reaches growing point. Caused by water trapped in crown + poor air flow.

Fix: Remove rotted leaves. Apply fungicide to crown. Increase air circulation.
Prevent: Water at pot edge. Fan for air movement. No misting crown.

Fertilizer Burn

Brown leaf tips, stunted growth. Salt buildup from overfeeding.

Fix: Flush media thoroughly with plain water. Reduce fertilizer strength/frequency.

Pests

Spider mites: Silvery stippling underside leaves. Webbing in advanced cases. → Neem oil or miticide.
Mealybugs: White cottony masses in leaf axils/roots. Sooty mold follows. → Alcohol swab + insecticidal soap/systemic.
Scale: Brown bumps on stems/leaves. → Horticultural oil + manual removal.
Slugs/snails: Chewed leaves/flowers at night. → Baits, copper tape, hand-pick.