Monstera pests, webbing or sticky leaves: causes and what to do
6 results in the diagnosis tree begin with pests, 5 of them marked likely when the answers fit. They are ordered here for Monstera (Monstera deliciosa), using what its sources say about pests and diseases, humidity and watering and 2 problems recorded for it.
Sources last read 14 September 2026.
Monstera deliciosa, the Swiss cheese plant or split-leaf philodendron, is a species of flowering plant. The common name "Swiss cheese plant" is also used for the related species from the same genus, Monstera adansonii. Wikipedia, CC BY-SA 4.0
Native range: Mexico (Veracruz, Oaxaca, Chiapas) to Guatemala (wet tropical). Also sold as ceriman, custard plant, Cutleaf Philodendron, fruit salad plant, Hurricane Plant and Indian ivy.
What Monstera’s sources say that bears on this
- Pests and diseases
- Usually no serious problems. Can be troubled by fern scale.NC State Extension · read 13 September 2026Greenhouse red spider mite and scale insects can attack it. Disease is uncommon.RHS · read 13 September 2026
- Humidity
- ASHRAE recommends indoor relative humidity between 30% and 60%Penn State Extension · read 11 September 2026
- Watering
- Water thoroughly, then let the upper quarter to one-third of the soil dry before watering again.NC State Extension · read 13 September 2026During growth water; in winter keep just moist.RHS · read 13 September 2026
How this shows up on a Monstera
Dull, finely mottled leaf blades and faint webs: spider mites
Seen side-on, the monstera looks dusty and bleached. Under a lens the undersides move with minute mites, and silk gathers where leaf blades meet the stem.
RHS lists spider mites among the pests it may attract. Mites empty the leaf cells one by one, which is what the pale dots are, and they breed fastest in warm, dry air.
Telling it apart: Tap a leaf over white paper. Dots that crawl are mites; dust stays still.
RHS · read 13 September 2026Small raised bumps along the stems and veins, with sticky leaf blades: scale insects
Rows of small, hard scales sit where the veins of the monstera are thickest, and the surface below them is glossy with honeydew.
RHS lists scale insects among the pests it may attract. Each scale sits in one place drawing sap and dripping honeydew, which is why the leaf blades below turn sticky.
Telling it apart: Stickiness below the bumps. Scale drips honeydew; a leaf spot is dry.
RHS · read 13 September 2026Possible causes, likeliest first for a Monstera
Most likely spider mites
Ranked higher because Monstera's recorded problems point this way.
- Dull, finely mottled leaf blades and faint webs: spider mites RHS
Why: Spider mites feed on individual leaf cells, and each emptied cell shows as a pale speck.
What to try:
- Move the monstera away from other plants.
- Wash the leaves, top and underside, with a strong spray of water in a shower or sink.
What would settle it: Hold a sheet of white paper under a leaf and tap the leaf. Tiny specks that move across the paper are mites.
Most likely scale insects
Ranked higher because Monstera's recorded problems point this way.
- Small raised bumps along the stems and veins, with sticky leaf blades: scale insects RHS
Why: Scale insects settle in one place under a hard or waxy shell and feed on sap.
What to try:
- Move the monstera away from other plants.
- Scrape the scales off with a fingernail or a soft brush, then wipe the stems and leaves.
What would settle it: Push a bump gently with a fingernail. Scale comes away and leaves a mark; a bump that is part of the monstera does not move.
Most likely mealybugs
Why: Mealybugs are soft insects that cover themselves in white wax, which gives the cottony look.
What to try:
- Move the monstera away from other plants.
- Wipe off every insect you can see with a cotton swab dipped in rubbing alcohol, testing a single leaf first.
What would settle it: Touch a tuft with a cotton swab. If a small, pale, oval insect is underneath, it is a mealybug.
Less likely for a Monstera, still possible
Questions
- What usually causes pests on a Monstera?
- For Monstera: spider mites, scale insects and mealybugs.
- How can I tell which one it is on my Monstera?
- What can you see? Fine webbing, and tiny pale speckles on the leaves; White, cottony tufts in the leaf joints; Small brown or pale bumps on stems and leaves that do not move; Clusters of small, soft insects on the new growth; Tiny dark flies around the soil; Sticky, shiny residue, but no insect I can see.
- What do Monstera's sources say about its pests and diseases?
- NC State Extension: Usually no serious problems. Can be troubled by fern scale. RHS: Greenhouse red spider mite and scale insects can attack it. Disease is uncommon.
- What does this look like on a Monstera?
- Seen side-on, the monstera looks dusty and bleached. Under a lens the undersides move with minute mites, and silk gathers where leaf blades meet the stem. Telling it apart: Tap a leaf over white paper. Dots that crawl are mites; dust stays still.
- Is Monstera safe to handle while I check it?
- Its sources list it as toxic to cats, dogs and people. Wash your hands after handling the roots or sap, and keep trimmings away from pets.
Other plants that show pests
AlocasiaFine pale speckling on the leaves, then webbing at the tips: spider mites
Arrowhead plantCurled, sticky new leaf blades with green or black insects: aphids
Dumb caneHard, rounded scale on the undersides of the leaves
Elephant earClusters of small soft insects on the shoot tips and buds: aphids
Heartleaf philodendronPale stippled leaves and tiny moving dots underneath: a mite pest
Lacy tree philodendronFine pale speckling on the leaf blades, then webbing at the tips: spider mites
Something else wrong with the Monstera?
What this does not cover
This page orders a decision tree's results using a plant's sourced care. It has not seen your plant, its pot or its window, and two problems at once are common: that is the usual reason a confident answer turns out wrong. The questions in the diagnosis tool narrow it further than a list can.