4 Ways to Get Rid of Thrips on Your Houseplants

Thrips are one of the flying insects that infest houseplants, and there are more than 7,700 known species of them. When you see one, you’re going to want to take action fast as females can begin laying eggs within 1 to 4 days after being born in warm climates or during summer, and within 10 to 35 days of being born in colder climates and winter.

Depending on the species of Thrip, they can lay between 10 and 100 eggs per reproductive cycle. Flower Thrip species may lay even more when they have pollen mixed into their diets. Much like other bugs that infest houseplants, Thrips eat the sap from the plant causing it to wilt and die. That’s why it is important to detect and treat the plant for Thrips the minute you find one.

Fun fact: All Thrips are winged, but female Mealybugs have no wings, only males do.

To identify a Thrip, look for:

• Slender and long bodies shaped like a grain of rice

• Two pairs of fringed wings

• Yellow, brown, tan, or black bodies

Fun fact: The fringed wings on a Thrip help to reduce drag during flight using a clap and fling flight technique.

Now that you know what a Thrip looks like, it’s time to do a white paper test and make sure the infestation is a Thrip one so you can be sure your treatment is correct. If it is not an insect, insecticides won’t be helpful and may cause more damage.

You will need:

• One piece of white paper

• A magnifying glass

To do the test:

1. Hold the sheet of white paper slightly curled underneath a leaf with the infestation.

2. Carefully shake the leaf until you see the pests fall into the paper.

3. Examine the paper under the magnifying glass quickly as they can jump and look for the signature Thrip body characteristics from above.

White paper is important here because you’ll be able to see the color of the body against it more easily. Once you have identified that you have a Thrip infestation, it's time to treat it.

Unlike spider mites, woodlice, and snails which are not insects, Thrips are and can be treated like most other insect infestations. Because adult Thrips are jumpers and fliers, you’ll likely benefit by hanging sticky paper or fly traps above the houseplant with the infestation to catch adults before they can spread to other plants.

Always make sure to separate any plant you see a Thrip on immediately from other plants to help prevent the infestation from spreading.

There are three easy ways to treat a Thrip infestation:

• Washing the plant

• Insecticides

• Horticulture oils

Fun fact: Thrips do not lay eggs on top of a plant leaf. The female uses a special organ to rip the plant leaf open and lay the eggs inside the plant tissue. This is why a single spray or treatment is normally not enough.

The simplest technique is to wash and rinse the plant every week.

1. Wipe the plant down with a clean and damp cloth then throw the cloth out or wash it in hot water.

2. Rinse the plant under a faucet or sprayer with a strong stream to remove any remaining Thrips and hopefully remove some of the eggs from the plant’s tissue.

3. Repeat weekly for three to four weeks. If the infestation continues, repeat until it is gone.

Insecticides are a great line of defense against Thrips and as a way to treat infestations. Make sure to follow the instructions on the one you buy, and use it as directed. 

Some oils including rosemary, horticultural, and neem can be used to treat Thrip infestations as they can each have a different impact. 

Rosemary oil is a natural deterrent to adults helping to get them to avoid the plant altogether. Neem oil has a similar impact as a repellent, and can help prevent larvae from maturing and reproducing. Much like neem oil, horticultural oil can suffocate adult Thrips and close off their ability to breathe. Once dead they can no longer reproduce.

To treat a Thrip infestation with oils, use the instructions on the bottle. Most will have a specific mixture recommendation with water, soaps, or detergents, and then they use similar instructions.

1. Create the appropriate mixture to treat the plant based on the oil.

2. Pour the mixture into a spray bottle.

3. Wipe the plant down with a clean, damp cloth and then throw the cloth away or wash it in hot water.

4. Spray the plant with the oil mixture making sure to cover every surface.

5. Let the plant dry.

6. Treat the plant weekly including one week after the infestation appears to clear as the eggs are inside the plant and you’ll want to kill any newly hatched Thrips.

Thrip infestations are annoying, but easy to get rid of once you realize you need to trap adults when they jump and treat the plant at least one week after the adults are dead as the larvae stay hidden. From there you’ll be able to get your plants back to healthy in no time.