Treating Scale on a Mature Indoor Yucca

Before treating, confirm it's scale: the bumps should scrape off with a fingernail and leave sticky honeydew. If it's scale, the infestation likely came in on the plant years ago and exploded when conditions favored reproduction.

Effective Non-Toxic Treatment

• Spray all leaf and stem surfaces until dripping with a mix of 1 part rubbing alcohol to 8–10 parts water plus a drop of liquid soap.
• Repeat in 5–7 days to catch newly hatched crawlers.
• Alternatively, use horticultural oil (Sun Spray Ultra-Fine) or a silicon-based foliage cleaner (Brand X).

Avoid rinsing after application—residual contact is key. Once treated, the plant poses no risk to neighbors; quarantine is unnecessary. Monitor weekly for recurrence.