Plant care guide

How to Prevent Thrips on Monstera Deliciosa (and Spot Them Early)

Updated

Why does my Monstera deliciosa have thrips?

Thrips feed on Monstera's leathery leaves and leave silvery, scarred or pitted patches with tiny dark droppings. The RHS lists Monstera among hosts of banded palm thrips, which are active all year indoors. Prevention rests on quarantine, regular leaf checks and wiping, and avoiding soft, over-fed growth.

What to do first

Isolate and inspect every new or returning plant, wipe both leaf surfaces regularly, and keep a blue or yellow sticky card nearby. If you find thrips, rinse the whole plant, refresh the potting mix and treat with a labelled soap or oil.

Thrips on a Monstera are worth preventing because Maryland Extension calls them hard to get rid of once established. The good news is that prevention is mostly routine: checking, wiping and quarantine. This page focuses on keeping them out, then on what to do if they arrive.

Why Monstera Gets Thrips

The RHS thrips page names Monstera among the hosts of banded palm thrips, with ficus, dracaena, citrus, schefflera and palms. It says this species occurs all year on indoor plants and causes extensive silvering of the leaves.

University of Maryland Extension’s thrips page lists the aroid family among commonly affected indoor plants. Monstera is an aroid. Maryland also notes thrips reproduce rapidly and readily become resistant to insecticides.

Know What Early Damage Looks Like

Monstera leaves are glossy and leathery, as NC State Extension’s Monstera profile describes. Damage shows differently on them.

  • Silvery patches. The RHS indoor sap-feeders page says leaves become dull or silvery and do not regain their colour.
  • Sunken scars. Maryland says that on thicker leaves, scarred areas may look sunken or pitted.
  • Dark specks. The RHS likens thrips droppings to small dollops of dark varnish.
  • Distorted new leaves. Maryland says leaves still expanding while thrips feed can stay stunted or crinkled.

Spider mites and scale cause other speckling. UConn’s Monstera factsheet describes spider mite damage as fine white stippling. Webbing points to mites rather than thrips.

Prevention Routine

  1. Quarantine new plants. Clemson Extension’s houseplant pests factsheet advises isolating new plants for six weeks. UC IPM’s houseplant problems page says to monitor new plants weekly.
  2. Check plants coming back indoors. UW–Madison Extension’s Monstera article notes Monstera can spend summer outside. Inspect it before it rejoins your other plants.
  3. Look in the right places. The RHS says thrips are more numerous on leaf undersides. Maryland adds young leaves, the main vein and the joints where leaf stalks meet the stem.
  4. Wipe the leaves. NC State advises wiping dust off Monstera leaves regularly. UC IPM says periodic washing of leaf surfaces can prevent many pests. Wiping doubles as an inspection.
  5. Hang a sticky card. UC IPM suggests blue or bright yellow sticky traps to detect flying thrips.
  6. Do not over-feed. Maryland says excess nitrogen produces tender growth that attracts thrips. UConn adds that Monstera is easily burned by high soil salts.
  7. Keep humidity up. Maryland says high humidity may discourage most thrips species indoors. NC State suggests a humidifier or wet pebble tray for Monstera.

If You Find Thrips

  1. Isolate the plant and check its neighbours.
  2. Rinse both sides of every leaf. UC IPM suggests washing thrips off and disposing of infested parts. Maryland says to spray both leaf sides.
  3. Refresh the mix. UC IPM says pupae often drop to the soil. Maryland notes repotting into fresh mix may remove them.
  4. Use soap or oil. Maryland lists horticultural oil and insecticidal soap. Sprays must contact the thrips, and repeat applications are needed.
  5. Escalate if needed. UC IPM calls spinosad generally more effective than contact sprays. Follow the label for indoor use.

The leathery leaves tolerate wiping well. Still, test any spray on one leaf first, as Clemson advises. UC IPM also warns against using soaps or oils on water-stressed plants, so water a dry plant first.

Judge Success on New Leaves

Silvered patches stay. Clean new leaves and an empty sticky card over several weeks show the problem is under control.

Our thrips guide covers life cycle and treatment in depth, and our pest treatment guide compares options. For other leaf damage, see Monstera brown spots and Monstera yellow leaves.

References

How this guide was put together: RHS, University of Maryland Extension, UC IPM, Clemson Cooperative Extension, NC State Extension, UConn and UW–Madison Extension guidance.

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Knowledge record: pg-monstera-deliciosa--thrips