The Thrips Plague

The silent plant murderer that hides in plain sight. The grim reaper who takes your beloved plants much too soon. The microscopic predator that has kept me up at night and haunted my dreams. THRIPS.

I knew if I ever started a plant blog, that this topic would be my first. Not because I love it the most, obviously, but because in my opinion, there isn't enough on the internet about it. I lost a plant very special to me, my baby Frank, to thrips back in 2017. He was my first and most loved Monstera Deliciosa and it had so much sentimental meaning to me. The day I had to chop him up into pieces is a day that will forever be burned inside of my mind. I literally sobbed the entire way through, then curled into bed for the rest of the day feeling like I had actually committed a crime.

I'll start from the beginning.

This was Frank in all his glory when I first received him as a gift from my husband.

Frank was beautiful. He was the perfect addition to our new space. I got him in October and he acclimated just fine despite a stressful move, and even pushed out a brand new leaf within the first few weeks. By Spring the following year, I noticed that his leaves were starting to look and feel a little wilted. I thought, okay, well it's growing season, he is likely pretty pot bound and is probably ready for some fertilizer. So I fertilized. Nothing. Over the next month the decline was happening on a daily basis and I noticed that I was starting to see what looked like tiny specks of dust on his leaves. Upon closer inspection, they were moving! I googled and googled and googled, nothing looked like what I had. The little critters were a pale yellow color, didn't move around very fast, no wings, no legs that I could see. This is what they looked like:

Keep in mind, this is a macro shot taken with a professional camera, so to the naked eye they definitely did not look like this.

Thrips had definitely come up a handful of times in my desperate Google searches, but most of the photos I found were black or white bugs, whereas mine was definitely yellow. I posted in multiple forums, Facebook plant groups, Instagram... No one seemed convinced that it was thrips, and neither was I. So I just brushed it off and hoped that a simple shower and treatment of insecticide would do the trick. About a week went by and I didn't see anything, so I assumed the bath worked. Another week goes by, and that's when I noticed the yellowing edges. I didn't think it was the thrips at first, I actually thought it was caused by the shower I had given it previously. Maybe the water hadn't completely drained from the pot and the roots were rotting? So I plucked it out of the pot, and lo and behold, healthy roots. But, in my search for root rot, I had a chance to see the damage that thrips could do in only 2 weeks.

All of the leaves had turned this copper color with tiny brown bumps that would not scrape off. Safe to say I freaked out since it didn't look like this when I first found the thrips. So again, I posted online hoping someone could help. Everyone said:

"Rust disease!"

"It's bacterial!"

"It's transferred through spores!"

"Probably got it from a new plant you just took home!"

"Root rot!"

"Low humidity!"

Basically it was everything under the sun besides thrips. How could no one identify what this was when it's something so specific? I was seriously at a loss. Again, if you Google search what thrips damage looks like, many sites and people will describe it as silver streaks, silver speckling, small white patches, etc. I didn't have any of that, so again, I didn't think it was thrips.

In a desperate attempt to save him, I basically took everyone's advice, which might've been the worst thing I could've done to him.

I fertilized again.

I moved him closer to the window.

I moved him away from the window.

I got him a humidifier.

I treated him with sulphur.

I repotted.

I amped up his watering routine.

I let him dry out.

Poor Frank. Poor, poor Frank. I know what you're thinking, and trust me, I'm embarrassed too. But please try and remember that this was my first ever ordeal with pests, with my first big plant, in a totally new country with a different climate than California, no solid plant community to rely on at the time, and it was just all so NEW to me.

Fast forward another two weeks and he was just looking so, so sad. I didn't take any photos because it was just too painful and I didn't want to remember this, and I also didn't know I would be making this blog and could turn it into an educational experience for someone else. But I do have a photo from a friend whose monstera was also overrun by thrips, and it's pretty much exactly what Frank looked like.

Sorry, it's not the best photo since this was just a screenshot from a video she sent me, but you can kind of get an idea. All of his leaves had started to turn a lighter green, with browning edges with a yellow halo around it. At this point, I figured it HAD to be thrips because it was the only constant thing throughout this entire ordeal.

In a nutshell, here is what I learned about my first experience with thrips and suggestions on how to treat your plant:

1. Cut off all affected leaves. Once they have turned yellow / brown, you can't go back from it. Cut the petiole as close to the stem as possible, since thrips also hide in the petiolar sheaths. If larger leaves have only been affected in small areas, you can take a scissor and trim off the browning areas if you don't want to cut off the whole leaf.

2. They will not be eliminated with one spray down in the shower, and maybe not even a handful of spray downs... but the more persistent you are with cleaning them off, the faster it will be to get rid of them completely and prevent them from multiplying.

3. You can't eliminate thrips by only treating the leaves. They live EVERYWHERE. You need to get into every nook and cranny of the petiole, the main trunk, all the way down to the soil. As a precaution for bad infestations, I would change out all of the soil if possible, or at least the top 2 to 3 inches. I recommend Bonide Systemic Insect Control in the soil and Diatomaceous Earth on the leaves. You can also use a spray thrip killer as well.

5. Females do not need a male to lay eggs, and they lay eggs within the soft tissue of plants, making it nearly impossible to get to them. This is why repetitive treatments and daily monitoring is a must.

6. Keep an eye on the undersides of your plant just as much as the top. Your monstera should not have any brown or copper color underneath it. This is damage from thrips. Many people confuse this as leaf burn, watering issues, or nutrient deficiency.

7. Keep it as far away from your other plants as possible. Isolate it and put it in plant jail. The thrips can easily and quickly spread to the rest of your plants, and if that happens, godspeed.

8. If spray treatments are not working, look into getting a beneficial predator bug like green lacewing. I have not tried this myself since I am a bit wary of releasing (even friendly) bugs in my apartment, but I know people who swear by this method.

9. And last but not least, do not give up easily! Armed with all this info + the endless (new) info you can find about thrips online and in the growing plant community, try everything you can before chopping up your plant completely. Monsteras are super resilient and will surprise you at how quickly they bounce back!

You can find everything I use to treat and prevent thrips in the "Plant Essentials" section of the website, or click directly down here:

USA

CANADA

Some of these things might also be available at your local hardware store or nursery too, so check there first!

If you're reading this, I hope it's not because you're dealing with thrips... But if you are and still need any advice, feel free to send me a message! You can also find more information about thrips here.