Why does my rubber plant have sticky residue on the leaves or the floor?

On a rubber plant this shows as a clear, tacky film on the glossy leaves, on the stem or on the floor and furniture below the plant. A large glossy leaf shows it long before you notice the insects themselves.

The most likely cause, as the entry says, is scale insects on the stems and the undersides of the leaves. The NC State plant toolbox lists mealybugs, scales and spider mites as the problems for this plant, and the Royal Horticultural Society names scale insects among the pests of ornamental figs under glass. Scale feed on sap and excrete the sugar, which is the sticky film.

To confirm it in a minute, run a finger along the stems and the veins on the underside of a leaf. Scale are small brown or fawn bumps, two to five millimetres across, that do not move and are easy to miss because they do not look like insects. A fingernail lifts one off, and there is a soft body underneath.

Two other causes are worth ruling out. Mealybugs look like white waxy fluff in the leaf joints and under the leaves, with the stickiness below them. And aphids on the soft new growth at the tips make the film worst directly below them, and ants are often nearby.

The film wipes off in a minute, but it returns until the insects are gone. Scale hatch crawlers over several weeks, which is why a single clean is not enough, and you judge the recovery by whether new sticky patches stop appearing over the following month. The plant itself carries on, and the thick leaves tolerate regular wiping, which the entry recommends every month or two.

What this plant wants

The fix

Scrape them off with a fingernail or a cloth, wipe every surface clean, and treat with an insecticidal soap weekly until nothing new appears.

Read on

Sticky residue on the leaves or the floor

The same sign on any plant, with the causes in the order they are likely.

Rubber plant care

Light, water, feeding, repotting and the rest of the entry.

Check it in the diagnoser

Opens with the plant, the part and the sign already chosen.