Diseases and pests

Scale insects

Spreads to other plants

What it looks like

Brown or beige bumps on stems and leaf undersides that will not wipe off and look like part of the plant. Sticky leaves, sometimes a black coating.

Why it happened

Brought in on a new plant. Adults have a hard shell that sprays cannot penetrate, so they must be removed mechanically.

What to do

1. Scrape off each shell with a fingernail or an old toothbrush. 2. Dab the spots with alcohol on cotton. 3. Spray with neem oil — that reaches the young ones, which have no shell yet. 4. Repeat weekly for 4–6 weeks. 5. Cut off heavily infested shoots.

How to prevent it

Inspect stems and leaf undersides regularly. Scale goes unnoticed for a long time.

Most common on these species

  • Sago palm
  • Lemon tree
  • Oleander
  • Weeping fig
  • Ginseng ficus
  • Umbrella plant
  • Olive tree
  • Japanese laurel
  • Coral berry
  • Cymbidium orchid
  • Bay laurel