Indian azalea 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 Indian azalea (Rhododendron simsii), using what its sources say about pests and diseases and humidity and 6 problems recorded for it.
Sources last read 14 September 2026.
Rhododendron simsii (杜鵑) is a rhododendron species native to East Asia, where it grows at altitudes of 500–2,700 m (1,600–8,900 ft). Wikipedia, CC BY-SA 4.0
Native range: S. China to Indo-China, Nansei-shotō to Taiwan (subtropical).
What Indian azalea’s sources say that bears on this
- Pests and diseases
- Aphids, caterpillars, scale insects, pieris lacebug, rhododendron leafhopper, rhododendron and azalea whitefly, and vine weevil can attack it. Disease risks: Phytophthora, silver leaf, honey fungus, powdery mildews, plus diseases specific to Rhododendron.RHS · read 13 September 2026
- Humidity
- ASHRAE recommends indoor relative humidity between 30% and 60%Penn State Extension · read 13 September 2026
How this shows up on an Indian azalea
Curled, sticky new leaves with green or black insects: aphids
Aphids gather on the undersides of new leaves and around buds on the Indian azalea, leaving honeydew and shed skins behind.
RHS lists aphids among the pests it may attract. They feed on the sap of soft new growth, which distorts it, and they multiply quickly without mating.
Telling it apart: Where they sit. Aphids crowd soft tips and buds; scale sits still on older stems.
RHS · read 13 September 2026Fine pale mottling on the leaves and white cast skins beneath: an insect pest
Touching the Indian azalea sends small, wedge-shaped insects leaping. The leaves they fed on are mottled pale.
RHS lists leafhoppers among the pests it may attract. They suck sap from the undersides, which leaves pale dead cells on the surface above.
Telling it apart: Whether the insects jump. Leafhoppers leap; whitefly flies up in a cloud.
RHS · read 13 September 2026Holes chewed in the leaves, with droppings: a caterpillar pest
Holes and ragged edges appear on the leaves of the Indian azalea, with small dark droppings on the leaves below. Some leaves may be rolled or tied with silk.
RHS lists caterpillars among the pests it may attract. They grow fast and eat more as they grow, so damage accelerates.
Telling it apart: Droppings. Caterpillars leave dark pellets below the damage; slugs leave slime.
RHS · read 13 September 2026Small white flying insects under the leaves
White, moth-like insects settle under the leaves of the Indian azalea and rise when disturbed.
RHS lists whitefly among the pests it may attract. Adults and young feed on sap from the undersides and shed honeydew, and warm indoor conditions keep them breeding.
Telling it apart: Stickiness with flying insects. Whitefly has both; fungus gnats fly but leave no honeydew.
RHS · read 13 September 2026Sticky leaves and immobile shell-like insects on the stems
Flat or domed bumps, tan to dark, line the stems and the midribs of the Indian azalea. They do not move, and the leaves beneath them are sticky or dusted black.
RHS lists scale insects among the pests it may attract. The shell protects the insect, so it survives a wipe that would clear aphids and keeps feeding.
Telling it apart: Whether the bumps sit on the veins. Scale follows the sap; spots from disease scatter across the leaf.
RHS · read 13 September 2026Sudden wilting from a root pest: vine weevil grubs in the potting mix
Irregular notches appear along the edges of the leaves of the Indian azalea, bitten at night by adult weevils; later the plant may wilt as grubs eat the roots.
RHS lists vine weevil among the pests it may attract. The adults feed at night and hide by day, so the notched edges are often the only sign above ground.
Telling it apart: The shape of the damage. Weevils bite notches from the edge; caterpillars eat holes anywhere.
RHS · read 13 September 2026Possible causes, likeliest first for an Indian azalea
Most likely scale insects
Ranked higher because Indian azalea's recorded problems point this way.
- Sticky leaves and immobile shell-like insects on the stems RHS
Why: Scale insects settle in one place under a hard or waxy shell and feed on sap.
What to try:
- Move the indian azalea 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 indian azalea does not move.
Most likely aphids
Ranked higher because Indian azalea's recorded problems point this way.
- Curled, sticky new leaves with green or black insects: aphids RHS
Why: Aphids cluster on soft new growth and flower buds, where the sap is easiest to reach.
What to try:
- Rub them off with fingers, or rinse them off in a sink or shower.
- Repeat every few days while new ones appear.
What would settle it: Look for the pale shed skins among the insects. Aphids molt as they grow, and the skins are left behind in the colony.
Most likely spider mites
Why: Spider mites feed on individual leaf cells, and each emptied cell shows as a pale speck.
What to try:
- Move the indian azalea 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.
Less likely for an Indian azalea, still possible
Questions
- What usually causes pests on an Indian azalea?
- For Indian azalea: scale insects, aphids and spider mites.
- How can I tell which one it is on my Indian azalea?
- 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 Indian azalea's sources say about its pests and diseases?
- RHS: Aphids, caterpillars, scale insects, pieris lacebug, rhododendron leafhopper, rhododendron and azalea whitefly, and vine weevil can attack it. Disease risks: Phytophthora, silver leaf, honey fungus, powdery mildews, plus diseases specific to Rhododendron.
- What does this look like on an Indian azalea?
- Aphids gather on the undersides of new leaves and around buds on the Indian azalea, leaving honeydew and shed skins behind. Telling it apart: Where they sit. Aphids crowd soft tips and buds; scale sits still on older stems.
- Is Indian azalea 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
African violetIrregular notches bitten from leaf edges by an insect pest
Barberton daisyCurled, sticky new leaves with green or black insects: aphids
Bearded irisRagged holes and slime trails: a slug or snail pest
Bigleaf hydrangeaClusters of small soft insects on the shoot tips and buds: aphids
Bird of paradiseDull, finely mottled leaves and faint webs: spider mites
Blue passion flowerPale stippled leaves and tiny moving dots underneath: a mite pest
Something else wrong with the Indian azalea?
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.