Plant care guide
Thrips on Philodendron: Signs, Checks and Treatment
Updated
Why does my Philodendron have thrips?
Thrips on a philodendron show up as pale stippling that turns silvery, yellow or bronze, with tiny black specks of excrement and sometimes crinkled new leaves. The insects are slender, under 2 mm long, and hide on leaf undersides and in unfurling leaves. Philodendron is a listed host.
What to do first
Confirm with the white-paper test and a hand lens, then isolate the plant. Rinse both leaf surfaces, cut off the worst leaves, and follow with an indoor-labeled insecticidal soap or oil, repeated. Discard a heavily infested plant along with its mix.
Thrips are frustrating on a philodendron because you usually see the damage before the insects. The good news is that a single plant caught early can be cleaned up. It takes repeat treatments, not one spray.
University of Maryland Extension lists the aroid family, including Philodendron, Alocasia and Anthurium, among the indoor plants thrips commonly attack (UMD: thrips). NC State Extension names philodendron as a host of banded greenhouse thrips, a species that sometimes gets indoors to feed on houseplants (NC State: banded greenhouse thrips).
Signs on a philodendron
- Stippling. Maryland describes pale flecking that turns silvery, or yellow and then bronze. Heavy feeding leaves patches of thin, silvery tissue.
- Black specks. Small, dark, tar-like spots of excrement near the damage (Maryland). UC IPM calls them varnish-like flecks (UC IPM: thrips).
- Crinkled new leaves. Maryland notes leaves fed on while young can stay stunted, crinkled or curled.
- Larvae on undersides. NC State says banded greenhouse thrips larvae gather on leaf undersides, later along the midribs.
- Early leaf drop. Clemson Extension says infested leaves may drop early (Clemson HGIC 2252).
UC IPM notes that damage often appears only after tissue expands. A new philodendron leaf can unfurl already scarred, even if the thrips have moved on.
Confirm before you treat
Maryland describes thrips as slender, rice-shaped insects 2 mm or less, tapered at both ends. Clemson says they range from yellowish to blackish.
- Tap a leaf over white paper and watch for tiny moving slivers. UC IPM recommends this test.
- Use a hand lens on leaf undersides and inside the newest unrolling leaf.
- Hang a blue or yellow sticky card near the plant. UC IPM suggests these to detect flying adults.
Rule out the look-alikes. Clemson says spider mites cause light speckling and a faded look, similar to thrips, so look for webbing. Dry, circular brown spots with no specks point to leaf spot instead. Our philodendron leaf spot guide covers those.
What to do
- Isolate the plant. Adults fly, so keep it well away from other aroids.
- Rinse both leaf surfaces. Clemson advises rinsing leaves with water. Maryland suggests a strong spray on both sides.
- Prune the worst leaves. UC IPM advises removing injured or infested parts. Damaged tissue will not recover.
- Spray an insecticidal soap or oil labeled for indoor plants. Clemson notes soaps only work on direct contact, so cover the undersides and the leaf rolls. Repeat as the label allows, because missed thrips keep breeding.
- Consider fresh mix. Maryland says repotting into fresh mix may remove pupae in the soil.
- Escalate if needed. UC IPM says spinosad may be more effective than soaps and oils. Use a product labeled for indoor use.
- Discard a heavily infested plant. Maryland says this is often simpler and cheaper than treatment.
UC IPM also says overwatering and nitrogen fertilizer can increase thrips numbers. Water and feed your philodendron at normal rates during treatment. Clemson’s philodendron factsheet recommends a dilute fertilizer.
Keep them out
Clemson advises isolating new plants for six weeks and checking them weekly. Inspect the newest leaf of any philodendron you buy before it joins your collection.
For the full life cycle, sticky-card use and spray options, read our thrips on houseplants guide. For other spot patterns, see the philodendron hub.
Related guides
Other philodendron problems we cover: yellow leaves, nutrient deficiency, new leaf stuck in its sheath, toxicity to cats, dogs and people, brown leaf tips.
References
How this guide was put together: University of Maryland Extension, UC Statewide IPM Program, Clemson Cooperative Extension and NC State Extension guidance.