How to Get Rid of Thrips on Houseplants

Pests are inevitable, and thrips are some of the worst! Here’s how to get rid of thrips on houseplants.

How to get rid of thrips on houseplants

If you’re a houseplant lover, you’ve probably heard of thrips. They are demon pests from houseplant hell, and when they move in to your plants, you’re in for the fight of your life. If I sound dramatic, it’s because as of writing this, I’m on the tail end of a battle with thrips on my big beloved monstera deliciosa.

But I’m getting ahead of myself. If you suspect your plant has thrips, you might be wondering, what are thrips? Where do they come from? Are my other plants infected? What did I do to deserve this when I am such a good plant parent? Me too. So let’s cover it all.

What are thrips?

Thrips can be found on houseplants and in outdoor gardens. There are thousands of different thrips species, but thrips generally are teeny tiny insects with wings—though they jump more than they really fly.

They take up residence on your plant because they think it’s delicious. They feed on them and suck the life out of them, literally. Female thrips lay their eggs in plant tissue, and one of the reasons they are so hard to control is that they do not need males to reproduce. Thrips have no need for men. And they are using their powers for evil instead of good.

Thrips will go dormant in the winter. In the spring when it starts warming up, females lay their eggs. They only take a few days to hatch if the weather is warm enough. The thrips lifecycle from egg to adult can take 1–2 weeks, and then adult thrips can live for 7 or so weeks. All of this is important because it helps explain why it’s so hard to get rid of them.

The little hatched babies are larvae and crawl around like pathetic little life suckers feeding on your plant’s foliage. It’s highly unlikely that you’ll ever see then at this stage because they are so small. Eventually they begin to grow into the prepupal phase and then pupal.

Many thrips then drop into the soil (because they don’t have their dumb wings yet) to develop into their adult form. The adults then emerge, buzz up to the plant, and start the process all over again! Feeding like stupid little kids in a stupid little candy shop.

What are the signs of thrips on houseplants?

Signs of thrips on your houseplants can look a lot like some other pest infestations: discoloration on the leaves (brown, grayish, sometimes yellowish), and leaves that grow distorted. One way to help narrow it down is if you see damage that looks like pests, but you can’t actually find any pests.

Thrips are tiny and can move or jump quickly, meaning you might miss them without a keen eye. But you might see small black spots about the size of a pin’s head near damaged spots. This is thrips poop. Yep, they eat your plant and then leave their poop as thanks.

Before I found the first adult on my monstera, I saw some minor yellowish discoloration and black spots on the undersides of the leaves. I also noticed some mildly deformed edges on the plant’s new growth and some smaller brown spots in the areas where the stems meet the leaves.

Once I saw this, I checked the plant until I found my first teeny tiny crawler. I went to poke it and it bounced away—the thrips bounce! Remember, they have wings but aren’t prolific fliers. This is when I began losing my mind—hopefully I can save you some of that.

Steps I took to get rid of thrips

Once I was reasonably certain that my monstera had thrips, I sprung into action. I am going to summarize all of the steps I took to isolate and treat the plant, including what worked and what didn’t. Let’s jump into it!

Step 1: Isolate the plant and inspect others

Thrips will spread, and they are pretty effective at doing so and multiplying. So the very first thing I did was isolate my monstera. We don’t have a big house, so there isn’t a ton of room for a large plant. So I moved it to the other side of the room. If you can truly isolate it in another room, do that.

Next I took a look at all of the plants that had been around my monstera to look for signs that the thrips had spread. I have a lot of plants, and many of them are very close together. So I decided to treat all plants that had been near my monstera.

Step 2: Treat the foliage

The first treatment step is to treat your plant’s foliage. Use an over-the-counter insecticide that states it targets thrips on the label, and follow all instructions for use. I used Captain Jack’s Dead Bug Brew, which is my go-to spray.

The name itself gave me hope, but so did the active ingredient: spinosad (.001% in the ready-to-use concentrate). Spinosad is a natural substance that comes from bacteria in soil. It is an effective insecticide when used as a topical spray. It works in a few days when insects ingest it or even touch it.

I also usually keep some of Bonide’s insecticidal soap spray on hand, which contains the active ingredient Potassium laurate. This is an effective spray for battling thrips on your plant’s foliage as well.

I went to town on my monstera, spraying the tops and bottoms of the leaves and stems until they were dripping. Because I was treating all plants that were next to my monstera as a precaution, I did the same with those plants.

While I was confident that this spray would work on adult thrips, I knew now that I needed to take more aggressive action to combat the longer thrips lifecycle. So I continued to spray my plants roughly once a week for about a month, either outside or in my tub. Then I moved below the surface of the soil…

Step 3: Treat the soil

I decided to use Bonide systemic houseplant insect control granules for plants that I had either seen thrips on or seen suspected damage on. The nice thing about the systemic control granules is that they protect your plants for 2 months or more. The active ingredient is Imidacloprid.

To use this insecticide, you put the appropriate amount (based on the size of the pot and plant) into the top 1–2 inches of soil. When you water the plant, the imidacloprid is released into the soil and root system. The plant then absorbs it, and it spreads throughout the plant.

This doesn’t hurt the plant, but it sure hurts the insects that try to eat parts of your plant! It damages their nervous systems, eventually killing them. I feel like this is really grim…like nerve agent stuff…but let’s remember who we’re fighting here.

With that thought in mind, though, I know that using this type of pest treatment isn’t for everything because it is more extreme. I would not recommend using this on plants that you’ll be bringing outdoors for the spring and summer since beneficial insects could potentially be affected by it. Read all instructions on the label before using.

If you do not want to use systemic granules, consider trying neem oil instead. But—with a disclaimer. Neem oil is not an effective way to kill adult thrips. Instead, it is effective only on larvae in the soil. So if you’d like to try that before systemics, there is research to support it. (Source: National Library of Medicine)

So…was my treatment a success?

Yes! About 6 or so weeks after applying the first round of systemic granules, I added a second round to my plants. I temporarily ceased any bottom watering so I could ensure the granules could do their job.

Knowing that I was looking at 8 weeks for a total thrip life—potentially longer if I wanted to be totally sure—I ultimately decided to alternate weeks with the dead bug brew (spinosad) and the Bonide’s insecticidal soap spray (Potassium laurate).

I initially wrote this article on 2021, and as of 2024, my monstera deliciosa is still alive and well. And thriving! After two rounds of systemic granules and about 8 weeks of weekly spraying, my plants showed no new signs of thrips.

Steps I’m taking to prevent future thrips

Needless to say, I’d like to avoid more thrips in the future. So here are the two main things I’m doing to prevent future issues with thrips.

• First, I am extremely strict about isolating new plants. I do not buy too many new plants these days simply because I do not have much more room. But when a new plant does come in, I spray it down with Captain Jack’s Dead Bug Brew and isolate it for a few weeks. If there are no issues, it can join my collection.
• Second, I began introducing beneficial mites to my routine in spring 2023. I purchased sachets of beneficial mites that target thrips and hung them from my plants as recommended by the company. This was preventative—just in case there was something overwintering in the soil that would wake up and ruin my spring.

In conclusion…

And that ends the world’s longest article on the world’s tiniest bastard of a bug. Can you tell I have strong feelings about thrips? 🙂 I really hope it helped you if you’re facing a thrips infestation! Comments? Drop them below!

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