Thrips Infestation on Indoor Ficus Trees: Identification and Control

Tiny Black Insects Curling Inside Ficus Leaves

You have three large ficus trees (8ft, 7ft, 4ft) in a south-facing 9th-floor apartment. New leaves remain curled, sheltering hundreds of tiny, slender black insects (3–4 cm long with legs) and some white ones. Ortho spray failed. You’ve been removing infested leaves, but they keep multiplying.

Identification: Thrips on Ficus

These are thrips – a major recent pest on ficus grown in Florida. They feed inside curled new leaves, making contact sprays ineffective. The “cocoon” is the leaf itself, folded around the colony.

Treatment Strategy

1. Prune heavily infested growth – Since thrips concentrate in new growth at stem tips, trim off the last several inches of every stem. This removes the bulk of the population immediately.
2. Choose a spray for thorough coverage – You must reach all leaf and stem surfaces to the drip point.
   • Malathion – Effective chemical option. Use only in a well-ventilated area (outdoors or garage). Follow label exactly.
   • Fine horticultural oil – Less toxic alternative. Also requires complete coverage.
3. Repeat as needed – Thrips have multiple generations; monitor and retreat if new curled leaves appear.

Important Notes

• Never spray in direct sun or above 75°F.
• Test spray on a few leaves first.
• Discard Ortho – it’s not formulated for thrips on ficus.

With aggressive pruning and proper spraying, you can save your trees. Let me know if you need clarification.