Do I Have Thrips?
How to spot thrips, recognise the damage they cause, find the insects hiding on your houseplants and know what to do next.
Thrips damage can become noticeable across several leaves before the insects themselves are spotted.
Thrips are one of those houseplant pests that can be surprisingly difficult to notice at first.
They're tiny, they often hide in new growth and leaf folds, and the first thing many plant owners notice isn't the insect at all — it's unusual marks appearing on the leaves.
Silvery patches, tiny black dots, distorted new leaves and mysterious scarring can all be clues.
First thing to know: thrips aren't always black
Adult thrips may be dark brown or almost black, but some species are considerably lighter. Young thrips are usually wingless and can be pale cream, yellowish or translucent.
If you're only searching your plant for tiny black insects, you could easily overlook the younger stages.
What do thrips actually look like?
Thrips are extremely small, narrow-bodied insects. Adults are commonly around 1–2 mm long, which makes them easy to mistake for tiny pieces of dirt or plant debris.
Adult thrips
Adults have long, narrow bodies and may appear brown, tan or almost black depending on the species.
They may move surprisingly quickly when disturbed.
Young thrips
Juvenile stages are smaller, wingless and often pale cream or yellow.
They're particularly easy to miss against pale new growth or leaf veins.
Adult thrips can be very dark and easy to mistake for a tiny piece of debris.
Young thrips can be pale cream or yellow rather than black.
Adult and juvenile thrips can look very different
Seeing the life stages together makes the difference much easier to understand.
A plant can contain dark adults at the same time as much paler juveniles, so inspect suspicious leaves carefully rather than looking for one particular colour.
Adult and juvenile thrips together on the same leaf.
Thrips eggs can be even harder to find because many species insert their eggs directly into plant tissue rather than leaving obvious clusters sitting on the surface.
What does thrips damage look like?
Thrips damage the surface of leaves while feeding on plant cells.
The damaged tissue can develop a dull, silvery, pale or slightly bronze appearance. Fine streaks, patches or irregular scarring may become visible as the leaf grows.
New growth can be particularly affected because thrips often feed while leaves are still folded or unfurling.
Pale or silvery feeding scars are a common clue that thrips may be present.
Common signs of thrips
- Silvery, pale or bronze patches on leaves
- Fine streaks or scarring across the leaf surface
- Tiny black specks around damaged areas
- Distorted or marked new leaves
- Damage appearing while leaves are unfurling
- Tiny narrow insects moving on the leaf
What are the tiny black dots?
One particularly useful clue is the presence of tiny black specks around suspicious feeding damage.
These can be thrips droppings, often referred to as frass.
A black speck that stays completely still is therefore not necessarily the insect itself.
Silvery damage + tiny black dots deserves a closer inspection
Neither sign proves thrips on its own, but finding both together is a strong reason to inspect the plant carefully for live insects.
Where should I look for thrips?
Don't just glance at the top of the leaves. Thrips often shelter in the places we naturally overlook.
Turn leaves over and look carefully along the veins and edges.
Pay particular attention to emerging, rolled or newly unfurled leaves.
Thrips often hide where leaves overlap or meet the stem.
Look for pale juveniles, narrow dark adults and tiny black specks.
If one plant has thrips, plants sitting close beside it should also be checked.
Try the white-paper test
If you suspect thrips but can't see anything clearly, hold a sheet of white paper underneath a leaf and gently tap or shake the leaf.
Tiny insects that fall onto the white surface are much easier to spot than they are against green foliage.
Use your phone camera or magnification if necessary. At this scale, a photograph can reveal details that are difficult to see with the naked eye.
Quick thrips check
- Look underneath the leaves
- Inspect new and unfurling growth
- Check for silvery feeding scars
- Look for tiny black specks
- Search for pale juvenile insects as well as dark adults
- Tap suspicious leaves over white paper
Is it definitely thrips?
Leaf damage alone isn't always enough to diagnose a pest.
Sun scorch, physical damage, oedema, nutrient problems and other pests can sometimes produce marks that look worrying in photographs.
That's why the most reliable diagnosis comes from combining the damage pattern with evidence of the insects themselves.
If you can find narrow moving insects, pale juveniles, fresh feeding marks and black frass together, the diagnosis becomes much stronger.
I've found thrips. What should I do?
Move it away from the rest of your collection where practical and inspect nearby plants.
Badly affected leaves can harbour pests and may be easier to remove, although don't strip a struggling plant unnecessarily.
Rinsing or carefully wiping the leaves can immediately reduce the number of insects present.
If using a pesticide or insect-control product in the UK, only use one currently approved and labelled for the intended plant and indoor use, and always follow the label instructions.
One treatment or clean-up is unlikely to tell you instantly whether the infestation has ended.
Why can thrips come back after treatment?
Thrips have several life stages.
Eggs may be protected inside plant tissue, while immature stages and adults may be present elsewhere on the plant.
Prepupal and pupal stages may also occur in sheltered areas or around the growing medium, depending on the species.
This means killing the insects you can see today doesn't necessarily remove every stage of the population.
Don't assume one treatment means they're gone
Keep inspecting the plant for fresh insects and fresh damage after treatment. Repeated monitoring is one of the most important parts of controlling thrips successfully.
Do I need to change all the soil?
Not automatically.
Some thrips species may use the growing medium or sheltered areas around the plant during part of their lifecycle, but that doesn't mean every plant with thrips needs to be completely bare-rooted and repotted.
Unnecessary repotting can add extra stress to an already struggling plant.
Concentrate first on correctly identifying the pest, treating the plant appropriately and monitoring it carefully.
Do sticky traps get rid of thrips?
Sticky traps can be useful for monitoring adult thrips and may help reduce the number of flying adults.
They shouldn't be relied on as the only treatment.
Eggs and immature stages can remain on or around the plant, so traps are best used as part of your monitoring rather than as a complete solution.
How will I know the thrips are gone?
Don't judge it by whether the old damaged leaves improve — they won't.
Instead, look for the absence of live thrips, no fresh black frass, no new silvery feeding marks and healthy new leaves opening without fresh scarring or distortion.
Continue checking the plant regularly for a while after the last insects are seen.
Old damage stays — watch the new growth
A leaf that has already been scarred by thrips will not return to perfect green tissue after treatment.
Healthy, undamaged new growth is a much better sign that the plant is recovering.
Quick thrips checklist
Look for
- Tiny narrow adult insects — dark or light depending on species
- Pale cream or yellow juvenile thrips
- Silvery or dull feeding patches
- Tiny black specks of frass
- Scarred, distorted or damaged new growth
Check
- Undersides of leaves
- Leaf veins
- New and unfurling growth
- Folds and sheltered areas
- Plants sitting nearby
One final tip
The easiest pest problem to deal with is the one you catch early.
Make a quick leaf check part of your normal watering routine. Turn over a couple of leaves, look at new growth and investigate unusual marks rather than waiting until damage spreads across the plant.
And whenever you bring a new houseplant home, give it a careful inspection before placing it amongst the rest of your collection.
Still not sure what's wrong with your plant?
Visit the Rare Leaf Plant Help Hub for straightforward guides to common houseplant problems including yellow leaves, root rot, drooping plants, fungus gnats and soil that stays wet for too long.
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