Diagnosing Brown Spots on Ming Aralia: Fungal or Environmental?

Ming aralia (Polyscias fruticosa) is prized for its delicate foliage, but brown, blister‑like spots on leaf undersides can signal trouble. While pests like scale are possible, the symptoms often point to a fungal issue or cultural stress.

Identifying the Cause

• Fungal infection: Small, raised brown spots that appear within leaf tissue, often with yellowing and leaf drop.
• Scale insects: Hard, circular bumps that scrape off easily and usually leave sticky honeydew.
• Watering/temperature shock: Sudden changes cause leaf yellowing and necrotic spots without pathogens.

Treatment Steps

1. Isolate the plant to prevent spread.
2. Apply a houseplant‑safe fungicide (e.g., a rose fungicide) every 3 days for a month, or use Lysol spray as a home remedy.
3. Move the plant outdoors in warm weather for better air circulation and light; continue periodic treatment.
4. Repot in fresh, sterile soil in early summer to eliminate lingering spores.

Monitor closely—new growth should be clean. If spots persist, consult a local extension service for lab diagnosis.