Bougainvillea 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 Bougainvillea (Bougainvillea glabra), using what its sources say about pests and diseases, humidity and watering and 4 problems recorded for it.
Sources last read 14 September 2026.
Bougainvillea glabra, the lesser bougainvillea or paperflower, is the most common species of bougainvillea used for bonsai. The epithet 'glabra' comes from Latin and means "bald". Wikipedia, CC BY-SA 4.0
Native range: E. & S. Brazil (wet tropical). Also sold as Lesser Bougainvillea, Paper Flower and Paperflower.
What Bougainvillea’s sources say that bears on this
- Pests and diseases
- Can be troubled by greenhouse whitefly, aphids, mealybugs and greenhouse red spider mite. Diseases: usually none.RHS · read 13 September 2026
- Humidity
- ASHRAE recommends indoor relative humidity between 30% and 60%Penn State Extension · read 11 September 2026
- Watering
- Lesser Bougainvillea suits a hot, dry climate; water it thoroughly but let it dry out between waterings.NC State Extension · read 13 September 2026From spring, as plants resume active growth, water more and use a balanced liquid feed until colour shows in the bracts, then change to a high potassium feed. In autumn, water less and stop feeding.RHS · read 13 September 2026
How this shows up on a Bougainvillea
Clusters of small soft insects on the shoot tips and buds: aphids
The youngest growth of the bougainvillea is sticky and distorted, and a closer look finds colonies of small, pear-shaped insects.
RHS lists aphids among the pests it may attract. They favor tender tips and buds, so the damage concentrates where the plant is growing.
Telling it apart: Whether you can see them. Aphids are visible to the eye; the mites that distort new growth are not.
RHS · read 13 September 2026Dull, finely mottled leaf blades and faint webs: spider mites
Speckling spreads over the bougainvillea until the leaf blades look washed out and bronze, with fine threads at the growing points.
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 white woolly insects tucked into the leaf joints
Clusters of white wax sit where each leaf blade joins the stem and along the undersides of the bougainvillea. Lifted with a cotton swab, each tuft holds a soft, pale insect, and the leaf blades below are sticky.
RHS lists mealybugs among the pests it may attract. Mealybugs pierce the stem and draw sap, which weakens new growth and leaves a sticky residue.
Telling it apart: Wipe a tuft with a cotton swab. An insect smears or crawls; a mineral deposit or a hair does not.
RHS · read 13 September 2026Sticky, yellowing leaf blades and a cloud of white insects: whitefly
White, moth-like insects settle under the leaf blades of the bougainvillea 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: Shake the plant. A cloud of white insects is whitefly; nothing else on a houseplant flies up like that.
RHS · read 13 September 2026Possible causes, likeliest first for a Bougainvillea
Most likely spider mites
Ranked higher because Bougainvillea'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 bougainvillea 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 mealybugs
Ranked higher because Bougainvillea's recorded problems point this way.
- Small white woolly insects tucked into the leaf joints RHS
Why: Mealybugs are soft insects that cover themselves in white wax, which gives the cottony look.
What to try:
- Move the bougainvillea 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.
Most likely aphids
Ranked higher because Bougainvillea's recorded problems point this way.
- Clusters of small soft insects on the shoot tips and buds: 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.
Less likely for a Bougainvillea, still possible
Questions
- What usually causes pests on a Bougainvillea?
- For Bougainvillea: spider mites, mealybugs and aphids.
- How can I tell which one it is on my Bougainvillea?
- 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 Bougainvillea's sources say about its pests and diseases?
- RHS: Can be troubled by greenhouse whitefly, aphids, mealybugs and greenhouse red spider mite. Diseases: usually none.
- What does this look like on a Bougainvillea?
- The youngest growth of the bougainvillea is sticky and distorted, and a closer look finds colonies of small, pear-shaped insects. Telling it apart: Whether you can see them. Aphids are visible to the eye; the mites that distort new growth are not.
Other plants that show pests
AlocasiaFine pale speckling on the leaves, then webbing at the tips: spider mites
Aloe veraSticky leaves and immobile shell-like insects on the stems
Areca palmDull, finely mottled fronds and faint webs: spider mites
Arrowhead plantCurled, sticky new leaf blades with green or black insects: aphids
Asparagus fernCurled, sticky new fronds with green or black insects: aphids
Bird's nest fernSticky leaves and immobile shell-like insects on the stems
Something else wrong with the Bougainvillea?
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.