Thrips on Plants: Signs, Treatment & Prevention

What Are Thrips?

Thrips are very small, slender insects that feed on plants by damaging plant cells and extracting their contents. Houseplant thrips are often about 1/16 inch long and can range from yellowish to brownish or black.

Because they are tiny and can stay hidden in flowers, buds and protected plant growth, an infestation may be easier to notice from the damage than from the insects themselves. Both adults and immature stages can feed on plants.

Common Signs of Thrips

Thrips can be difficult to spot because they are small and may stay hidden inside flowers, folded leaves or other protected areas.

Where Should You Look for Thrips?

New leaves and growing tips

Inspect tender new growth for distortion, scarring or pale damage.

Flowers and buds

Thrips can hide in flowers and buds where they are difficult to see.

Leaf undersides and protected areas

Check both sides of leaves, leaf folds and places where plant parts overlap.

Try the white-paper test

Gently tap a suspicious plant over white paper. Tiny thrips may fall onto the paper and become easier to spot.

Thrips Damage vs. Other Common Pests

Signs can overlap, so use several clues before identifying the pest.

How to Manage Thrips on Plants

1. Isolate the affected plant

Move a suspected infested plant away from nearby plants while you inspect and manage it.

2. Remove heavily damaged material

Prune severely damaged leaves or flowers when appropriate and dispose of infested material.

3. Wash the plant

A gentle spray of water can help dislodge some pests from foliage. Washing leaves and stems is one physical management method.

4. Use sticky cards for monitoring

Sticky cards can help detect adult thrips and track activity. They are a monitoring tool and do not address every life stage.

5. Consider an appropriate labeled treatment

Insecticidal soaps and other products may be used depending on the plant, location and product label. Always use only products labeled for the specific plant and site and follow label directions.

Why Are Thrips Difficult to Control?

Thrips can hide in flowers, buds and tightly folded plant growth, making complete coverage difficult. Some species also reproduce quickly and can develop resistance to insecticides.

For houseplants, repeated inspection is important because different life stages may be present at the same time.

How to Prevent Thrips

1. Inspect new plants carefully before adding them to your collection.
2. Keep new or suspicious plants separated while monitoring them.
3. Check new growth, flowers and leaf undersides regularly.
4. Remove badly infested plant material promptly.
5. Keep growing areas clean and remove unnecessary plant debris.
6. Use sticky cards as an early monitoring tool.
7. Avoid unnecessary pesticide applications that can harm beneficial insects.

Can Thrips Affect Any Plant?

Thrips occur on many ornamental plants and can feed on leaves and flowers. The exact species and level of damage vary by plant and environment.

If a plant develops unexplained scarring or distorted new growth, inspect it closely rather than assuming the cause is watering, light or fertilizer.

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