⚠ ModerateFiddle Leaf Fig Scale Insects — Brown Bumps on Stems & Leaf Undersides
Commonly affects: Ficus lyrata (Fiddle Leaf Fig) — and other Ficus species
Small, round or oval brown bumps (2-4 mm) appear along stems, at branch junctions, and on the underside of leaves near the midrib. The bumps are hard-shelled and do not move when touched. Leaves become sticky with honeydew and develop black sooty mould. The plant gradually declines with yellowing leaves and reduced vigour. Scale insects (Coccidae and Diaspididae families) are among the most difficult houseplant pests to treat because their waxy or armoured shells protect them from contact insecticides.
Potential Causes
- 1Introduction via infested plant purchases — scale is invisible at the egg stage and easily missed at the crawler stage
- 2Low humidity and warm conditions accelerating scale reproduction
- 3Stress from other factors (overwatering, low light) reducing the plant's natural resistance to pest colonisation
Solution Steps
- 1Physically remove adult scale by scrubbing stems and leaf surfaces with a soft toothbrush dipped in 70% isopropyl alcohol.
- 2Follow with a neem oil drench (5 ml/L with dish soap emulsifier) applied to all plant surfaces weekly for 6-8 cycles.
- 3Apply a systemic insecticide (imidacloprid) as a soil drench — the plant absorbs it and makes its tissue toxic to feeding scale at all life stages.
- 4Treat every 7-10 days to intercept mobile crawler stages, which are the only life stage fully vulnerable to contact treatments.
- 5Inspect the plant meticulously with a magnifying lens 3-4 weeks after the last visible adult is removed — crawler infestations are nearly invisible.
- 6Isolate from all other plants throughout treatment.
Prevention Tip
Inspect Ficus lyrata stems and leaf midribs monthly under good light with a magnifying lens. Early detection when populations are small makes scale vastly more manageable.
