White "Mold" on Majesty Palm? It's Actually Scale Insects

An indoor majesty palm in Albuquerque has a white, mold-like coating. The owner tried soapy water and plant oil without success. What is it and how to treat?

Identification: Scale, Not Mold

The white coating is scale insects—small, immobile pests that attach to fronds and stems. They secrete a protective waxy covering that looks like mold or fungus.

Effective Treatment Protocol

1. Spray thoroughly with horticultural oil or insecticidal soap (follow label directions).
2. Let sit 6–8 hours to suffocate the scale.
3. Take the palm outside and hose off all dead scale and residue.
4. Repeat if necessary—scale often requires multiple applications.

Why Oil/Soap Works

These products physically smother the insects rather than relying on toxicity. They're safe for indoor use when applied correctly and provide reliable control of scale, mealybugs, and mites.