House Plant Pest Profile: Thrips

Thrips, like mealybugs, were not forthcoming with the stock photos. Maybe they’re shy.

Oh well.

Unlike mealybugs, I’ve never actually had thrips (I don’t think) so you’ll just have to google images if you want to know what they look like. I assure you, if I get them, I’ll share the pictures.

***UPDATE*** I got thrips. Yay. Here they are (the little pale things that look like rice):

These are the larvae. The adults are black and skinny. If you can kill the larvae (the ol’ squish trick) before they turn into adults, you may be able to halt the life cycle in its tracks.

I have also have…something on my fern, which is either black thrips or black aphids.

They’re aphids. Thrips look like moving rice, though they don’t move very fast. Aphids are rounder and fatter.

Aphids are simple to great rid of – introduce ladybirds. Whether that’s by putting the plant outside or by releasing some ladybirds indoors is entirely up to you (the former works perfectly well, provided the weather isn’t doing something that’ll fuck up your plants (wind/excessive sun/cold etc).

What do thrips look like?

There are over 6000 species of thrips, which is…well, it’s a lot. They come in many colourways, but black or light yellowish-brown seem to be the most common variations.

Thrips are teeny tiny – between half a millimetre and half a centimetre long. Many people report them as looking like little threads, or worms, if you fancy imagining a really gross image.

Some of the thrips species are rather fancy, and have a set or two of fringed wings, though they’re not particularly good for flying. I’m assuming it’s all about impressing the other thrips.

If you see spots on your plant’s leaves that look like halos, they could very well be thrips eggs.

Which plants do thrips prefer?

From what I’ve read, thrips dgaf. They’ll go for any plant that looks delicious to them.

They bloody love a Monstera though. Luckily, Monstera are pretty hardy. If you keep an eye on your plants you can usually get rid of thrips before they become too much of an issue.

Where do thrips congregate?

Like a lot of bugs, check the undersides of leaves, and the part where the leaf meets the stem. They will move all over the leaf though.

Thrips are tiny, but you can see their…leavings (poo) on the leaves – if your plant is sporting some silvery flecks on its leaves you could be seeing thrips poo.

Thrips move a lot more than a lot of other plant pests, and they’re pretty easy to see. If you see little pale grains of rice on your leaves, congrats: you have thrips

How did my plant get thrips?

It most likely had them when you got it BUT thrips can be carried in on the wind. Maybe you had your windows open and a thrips blew in.

Like a lot of bugs, thrips can breed asexually, so one can turn into hundreds pretty quickly.

You can also carry them in on your clothing. There’s not a lot you can do to stop doing that, other than maybe wear blue. You’ll have to read on to find out why (it’s b/c thrips like blue).

They will turn up though. I don’t know where or when, but they will.

What damage to thrips do?

Look out for bleached-looking leaves, or yellow spots on the leaves. Thrips can also cause new leaves to grow in a deformed way. A thrips infestation can cause leaf drop, though the leaf will thin and wilt first.

Thrips love flower buds too, so if you have a lot of buds that drop, or blooms that are emerging deformed, you may have a thrips issue.

Not all of the 6000 species of thrips eat plants – some of them feast on animals instead. These species can bite humans, but it usually only causes minor skin irritation and is unlikely to turn into anything more serious.

What conditions will thrips thrive in?

Unlike mealybugs and fungus gnats, thrips love hot and dry conditions. Be sure to keep your humidity up and the top of your soil moist.

This may be one of the few actual things misting can help with. Moistening your plant’s leaves and the soil may deter both thrips and spider mites.

It will encourage mealybugs and fungus gnats though.

FFS.

*edit* thrips don’t care. They turn up regardless. I don’t think they’re that difficult to keep under control, but you must keep a close eye on your plants.

How to control and eliminate thrips

First, you need to be sure that you actually have thrips, as opposed to some other beastie. The best way to do this is to shake your plant on a white surface – a piece of paper will do if you don’t have any white surfaces.

Thrips are fast-moving, especially when disturbed, and you’ll see what look like little be-legged worms dashing around on the paper.

The methods for eliminating thrips are similar to getting rid of any plant pest – be sure to first remove any damaged leaves and chuck any plant that you think is beyond saving.

Spray the plant with a neem oil mix or a bug spray made up of washing up liquid and water.

If possible, take your plant outside and hose it down – this should blast off a decent amount of thrips.

Introducing thrips predators such as ladybirds, lacewings, or the cool-sounding minute pirate bug is also an effective way of getting rid of thrips infestations. Hopefully you won’t end up with a ladybird infestation.

You will need to keep treating your plant for…yonks.

Why?

WELL

Thrips lay their eggs INSIDE THE LEAF. So you can’t simply wipe the eggs away. GROSS.

Preventative measures to ward off thrips

You can use those sticky traps that people use to catch fungus gnats if you like. I personally don’t like them – they seem unnecessarily cruel and look grim.

If you do go down that route then be aware of who you’re shopping for – fungus gnats like the yellow traps, but you’ll have more success catching thrips if you use the blue ones.

The more you know. I’m assuming that they’ll be attracted to blue in all forms, so if you wear blue tops outside you’re risking picking up a thrips or two.

Inspect plants before you buy them. I say this in every post but it’s the first line of defence against introducing unwanted pests into your plant collection. I’m considering investing in a magnifying glass.

I made this one up, but I believe it’s worth a try…shut your windows on windy days. Don’t invite those bastards in through the open window.

When you wash your plants (read about why you really should be washing your plants here), do so with a solution of neem oil and water.

As well as potentially suffocating any adult bugs with the oil, neem oil puts undesirable bugs’ hormones all out of whack and stops them from breeding.

Notes

• A single thrips is called a thrips, not a thrip. Which is why I’ve referred to them in that manner throughout the article. Kinda the opposite of how a sheep is a sheep but many sheep are also sheep.
• Do any bugs need males to reproduce? Do any bugs mate for life? Plant pests don’t seem to have a romantic bone in their body. If indeed they had bones, which they don’t.

So far I’ve evaded thrips (I think), probably because my house is pretty humid and not many plants get the chance to be bone dry.

I’ll definitely have to be vigilant in summer, but I’m ready!

I’m hoping that writing so often about why it’s so beneficial to clean your plant leaves with neem oil will spur me on to actually do it.

I’ve gotten into bad habits when it comes to leaf dusting, the worst one being that I just wipe any disty leaves I spot with my dressing gown sleeve.

Any thrips info that you have that we need to know would be gratefully received in the comments. Thanks!

*edit*

Lol, I got thrips. They were fine. They keep turning up on my Monstera and I keep wiping them off, and they’re not multiplying massively quickly or doing much damage.