Monstera: sticky leaves, or a sticky surface below the plant

What it is likely to be on monstera

1. Scale insect

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Scale insects

   Checked 2026-08-13

   Immobile brown or straw-coloured bumps along stems and leaf veins, which look far more like part of the plant than like an animal. That is why they are usually noticed indirectly — through sticky honeydew and sooty mould — long after the population has established.

   Points towards it

   • · all four have thick evergreen leaves with a pronounced midrib, which is exactly where soft scale settles and stays
   • · scale persists indoors year-round with no winter to knock it back

   Argues against it

   • · scale does not spin webbing

   Check this next

   Run a fingernail along the midrib on the underside of a leaf and along the stems. Scale insects are flat brown or straw-coloured bumps that look like part of the plant until they scrape off, and on these four they line up along the midrib rather than scattering. The give-away is that the stickiness is worst on the leaf BELOW an infested one, and on whatever the plant is standing on.

   What to do now

   Wipe them off with a cloth and soapy water, checking the midrib undersides and the leaf joints — a thorough wipe every week for a month clears a light infestation because the crawler stage is what spreads and it is short-lived. Wash the sticky residue off the leaves at the same time or sooty mould will grow on it and block the light.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Scale insects — control

   Checked 2026-08-13

2. Mealybug

   Candidate 2common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mealybug

   Checked 2026-08-13

   Sap-feeding insects that cover themselves in white waxy fluff and shelter in leaf joints, under leaf bases and among roots. On a houseplant the white fluff in the crevices is unmistakable, and the reason infestations persist is that the sheltered positions are exactly the ones a casual wipe-down misses.

   Points towards it

   • · mealybug shelters in crevices under a coat of white wax
   • · it is almost entirely an indoor and glasshouse insect in Britain

   Argues against it

   • · brown bumps are scale, which does not produce wool

   Check this next

   Look where a leaf meets a stem, and on an orchid look under the loose papery sheaths on the flower spike and along the aerial roots. Mealybug hides in the tightest crevices the plant offers and is white and woolly rather than brown and flat — and on these four the deep leaf joints and sheaths give it far better cover than the open leaf surface a scale insect uses.

   What to do now

   Dab each visible colony with a cotton bud dipped in surgical spirit, then check again after a week — the wax repels water, so wiping alone leaves enough behind to rebuild. Look at the roots when repotting: root mealybug is the reason an apparently cleared plant keeps coming back, and it is invisible until the plant is out of its pot.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mealybug — control

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on monstera — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general sticky leaves, or a sticky surface below the plant page lists causes across all plants, and the Monstera profile lists the problems it is prone to.