Blue passion flower 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 Blue passion flower (Passiflora caerulea), using what its sources say about pests and diseases and humidity and 4 problems recorded for it.
Sources last read 14 September 2026.
Passiflora caerulea, the blue passionflower, bluecrown passionflower or common passion flower, is a species of flowering plant in the family Passifloraceae. It is native to South America and has been introduced elsewhere. Wikipedia, CC BY-SA 4.0
Native range: Bolivia to Brazil and N. Argentina (subtropical). Also sold as blue crown, Blue Passionflower, Bluecrown Passionflower, common passion flower, Common Passionflower and flower of five wounds.
What Blue passion flower’s sources say that bears on this
- Pests and diseases
- Can be troubled by barnacle scale, plus the phlox plant bug and related Lopidea plant bugs.NC State Extension · read 13 September 2026In a greenhouse, scale insects, mealybugs, greenhouse whitefly and greenhouse red spider mite can occur. Diseases: a virus and, rarely, honey fungus.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 a Blue passion flower
Pale stippled leaves and tiny moving dots underneath: a mite pest
Speckling spreads over the blue passion flower until the leaves look washed out and bronze, with fine threads at the growing points.
RHS lists spider mites among the pests it may attract. Heated rooms suit them: dry, warm air speeds each generation, and the damage builds within weeks.
Telling it apart: Webbing. Only mites spin fine silk at the shoot tips.
RHS · read 13 September 2026Small white woolly insects tucked into the leaf joints
The blue passion flower carries white, cottony specks in its crevices, and growth slows. Leaves beneath the colonies turn sticky and, in time, dull or yellow.
RHS lists mealybugs among the pests it may attract. They feed on sap and shed the excess as sticky honeydew, and a colony tucked into the joints spreads before it is noticed.
Telling it apart: Where the white is. Mealybugs gather in joints and under leaves; a powdery coating across the top of a leaf is mildew.
RHS · read 13 September 2026Sticky leaves and immobile shell-like insects on the stems
Rows of small, hard scales sit where the veins of the blue passion flower are thickest, and the surface below them is glossy with honeydew.
RHS lists scale insects among the pests it may attract. The insect settles under a waxy shell and feeds on sap for life, so a colony builds quietly along the stems.
Telling it apart: Stickiness below the bumps. Scale drips honeydew; a leaf spot is dry.
RHS · read 13 September 2026Sticky, yellowing leaves and a cloud of white insects: whitefly
Brushing the blue passion flower lifts a cloud of tiny white insects. The undersides of the leaves carry pale, scale-like young, and the surfaces below are sticky.
RHS lists whitefly among the pests it may attract. Their honeydew is what makes the leaves sticky and lets a black film grow on them.
Telling it apart: What lives under the leaves. Whitefly young are flat, pale ovals; mealybugs are woolly.
RHS · read 13 September 2026Possible causes, likeliest first for a Blue passion flower
Most likely spider mites
Ranked higher because Blue passion flower's recorded problems point this way.
- Pale stippled leaves and tiny moving dots underneath: a mite pest RHS
Why: Spider mites feed on individual leaf cells, and each emptied cell shows as a pale speck.
What to try:
- Move the blue passion flower 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 Blue passion flower'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 blue passion flower 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 scale insects
Ranked higher because Blue passion flower'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 blue passion flower 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 blue passion flower does not move.
Less likely for a Blue passion flower, still possible
Questions
- What usually causes pests on a Blue passion flower?
- For Blue passion flower: spider mites, mealybugs and scale insects.
- How can I tell which one it is on my Blue passion flower?
- 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 Blue passion flower's sources say about its pests and diseases?
- NC State Extension: Can be troubled by barnacle scale, plus the phlox plant bug and related Lopidea plant bugs. RHS: In a greenhouse, scale insects, mealybugs, greenhouse whitefly and greenhouse red spider mite can occur. Diseases: a virus and, rarely, honey fungus.
- What does this look like on a Blue passion flower?
- Speckling spreads over the blue passion flower until the leaves look washed out and bronze, with fine threads at the growing points. Telling it apart: Webbing. Only mites spin fine silk at the shoot tips.
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
Bush lilySmall white woolly insects tucked into the leaf joints
Something else wrong with the Blue passion flower?
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.