Mealybug Infestation on Orchids: Identification and Complete Eradication

What You're Seeing: Mealybugs, Not Fungus

White cottony/gooey patches, oozing, spreading to multiple plants—classic mealybug infestation. These sap-sucking insects hide in leaf axils, under sheaths, on roots, and in pot crevices. They excrete honeydew (the goo), which grows sooty mold.

Nuclear Option: Complete Reset (Recommended for Heavy Infestation)

1. Discard ALL old medium and pots—they harbor eggs, crawlers, adults.
2. Buy fresh orchid mix and new plastic pots with lots of drainage.
3. Swab every plant surface with alcohol-soaked cotton swabs—remove every visible bug.
4. Systemic insecticide drench: Use a mealybug-effective product (imidacloprid, dinotefuran, or acephate). Soak entire plant (roots + foliage) per label. Wear gloves!
5. Dry plants completely before repotting in fresh mix/new pots.
6. Isolate and monitor for months—re-treat if any reappear.

Why This Works

Mealybugs have overlapping generations in old medium. Alcohol kills on contact but misses hidden ones. Systemic drench poisons sap—kills feeders you can't see. Fresh start eliminates reservoir.

Prevention

• Inspect new plants thoroughly; quarantine 3 weeks.
• Check leaf axils, root zones, pot rims monthly.
• Keep growing area clean; remove dead leaves/flowers promptly.
• Good air circulation discourages all pests.