How to get rid of tropical thrips

The complete guide

Hercinothrips

Difficulty High

Frequency High

Reproductive rate

Lifecycle

Tropical thrips are plant pests with a dark, slender body that pierce plant leaves to feed on their sap. They cause significant damage, and their rapid reproduction can lead to a gradual weakening of the plant.

All plants

Tropical plants

Identifying tropical thrips

Before starting treatment, make sure you have correctly identified the pest. Tropical thrips should not be confused with indigenous thrips. Here are the main signs of a tropical thrips infestation:

Early infestation

Presence of white or yellow larvae

Advanced infestation

Silvery streaks on the leaves
Small black dots near damaged areas
Presence of brown or black adults
Yellowing and necrosis of the foliage

Treatment options

Indoor plants

Small greenhouses

Prevention

You will need :

Scissors / Pruners
Plastic bags

Natural predators :

How to treat tropical thrips?

The most effective and safe strategy is to dislodge the majority of tropical thrips using a strong water jet and introduce natural predators to detect and eliminate any remaining individuals. Amblyseius swirskii and green lacewings will simultaneously target larvae, pupae, and adults.

1

Preparation

Cutting a damaged leaf in a tropical plant

Cut off damaged leaves

Damaged leaves and flowers usually harbor thrips eggs. If possible, cut them off.

Removing debris from the soil of a tropical plant

Remove debris

Remove dead leaves and other debris that may interfere with the treatment.

Wrap the pot

Wrap the pot in a plastic bag to protect the root ball during the treatment.

2

Cleaning

Prepare a workspace

Prepare a workspace that can get wet; ideally outside, in the sink or in the bathtub.

Adjust the water

Use the strongest jet of water possible without damaging the plant (hose, faucet, showerhead, etc.).

Cleaning a tropical plant with a powerful water jet

Wash the leaves and stems

Generously spray all leaves and stems. Cover all angles in several passes.

3

Drying

Let the plant dry

Wait for the leaves to be completely dry before introducing predators.

4

First introduction

Installation of green lacewing strips in the foliage of a tropical plant

Introduce the lacewings

Install the lacewing strips in the plant’s foliage.

Introduction of bulk predatory mites into a tropical plant

Introduce the swirskii

Distribute the bulk swirskii using small containers.

5

Second introduction

Repeat the introduction

Wait three weeks and repeat the same introduction (lacewings and swirskii).

A few important points

Natural predators are particularly effective at detecting hidden tropical thrips once their population has been reduced. The more thorough the initial cleaning, the higher the chances of success.
Tropical thrips eggs are laid inside the leaves and remain protected from cleaning, predators, and contact insecticides. At least two introductions at three-week intervals are necessary to eliminate the remaining larvae.

Once the treatment is complete

Inspect the plants regularly for at least eight weeks. If new signs of tropical thrips appear, repeat the cleaning of affected plants every five days. Otherwise, you can consider your treatment successful. We recommend using the preventive treatment to avoid a new infestation.

Do I absolutely need to treat all my plants?

Tropical thrips spread quickly, and the absence of symptoms does not mean the plants are healthy. It is therefore strongly recommended to treat all plants simultaneously. However, you can isolate plants that appear healthy and apply only the preventive treatment to them.

What should I do if I cannot wash a plant with a water jet?

If washing the plant with a water jet is not possible, you will need to reduce the tropical thrips population by other means. A common alternative is the black soap foliar treatment. Spray it very generously to saturate all surfaces of the plant, without exception.

Do I need to repeat cleaning before each introduction?

Cleaning is always necessary before the first introduction. If the initial infestation was severe or many insects are still visible at the time of subsequent introductions, it is preferable to carry out another pre-introduction cleaning. Conversely, it is no longer necessary once the infestation appears to be under control.

Is it necessary to replace the substrate to treat tropical thrips?

It is not necessary to replace the soil as tropical thrips do not have a developmental stage in the substrate. However, highly aerated substrates such as sphagnum moss or wood chips can harbor thrips, and replacing them may be useful.

Is diatomaceous earth effective against tropical thrips?

The effectiveness of diatomaceous earth is limited because its action does not last long enough to cover a full life cycle of tropical thrips. Note that it is also incompatible with the use of predators.