Persistent Scale on Pregnant Onion and Sansevieria: Root Cause and Eradication

A reader has scale on six pregnant onion plants (Ornithogalum caudatum) and a Sansevieria. Rubbing alcohol wipes give temporary relief. Asks if cutting all leaves and soaking bulbs in alcohol would work, or if they should compost and start over.

Scale Attacks Stressed Plants

Common stressors: air too dry, overwatering, or underwatering. Pregnant onions and Sansevierias need soil very dry for 4–6 days between waterings. Expert waters every 10 days in summer, 14–20 days in winter.

Aggressive Alcohol Spray Protocol

1. Fill spray bottle with rubbing alcohol.
2. Spray every 2 days for 2 weeks, then every 3 days for 1 week, then twice weekly for 3 months.
3. Cover all surfaces (front/back of leaves, soil surface).
4. Eggs hatch in cycles; persistence kills juveniles.

Don't give up—persistence works. Expert owns both plants and confirms this method.