I would have to say that it's most likely the geniculum, which is a perfectly normal part of the leaf structure. This helps the plant move the leaf blade to a position where it'll receive as much sunlight as possible throughout the day.

I shared a photo from the Exotic Rainforest website that perfectly illustrates this..

Also, what you're referring to as the stems are actually the petioles. The petioles attach the leaf to the actual stem of the plant. There's no need keeping them tied together. They would fare much better being more spread out. This way they don't have to compete with each other for sunlight. I would focus more on securing the actual stem of the plant to the pole instead.

I don't use a moss pole for mine. Mine just has a metal rod holding it up, because it seems to be the only thing strong enough to support my "monster."

<?xml version="1.0" encoding="UTF-8"?><md>@Photo Synthesis - thank you for the detailed response! Very helpful! and that twine is coming off

I meant to attach a photo of mine from a couple of years ago, just to give you a better idea of how mine is supported...

I had to use these adjustable rubber ties, because nothing else seemed strong enough or durable enough to last. I still have these same ties holding it up, and I've even managed to tighten them up some to straighten the vines out more. It's best to train them upwards as soon as possible, because they're not exactly flexible once they've established themselves. I have managed to tighten these ones up some more earlier this year, and now I'll probably add more rubber ties further up now that they're getting a bit taller.

The aerial roots just grow over the sides, and I let them hang down. I have it on a plant stand, and some of the older roots just lay on the ground.

Again, this photo is a couple years old. The first photo was of the back side. This is the front. Now that I look at it, I've come to realize that many more roots are hanging over the sides than what you see here. They would attach themselves to the ground, but I'm always moving it around whenever I'm watering my plants or mowing the lawn.

I actually don’t think it’s a normal part of the plant. I’ve had two huge monsteras die (one I had for 10 years) quickly after those brown scabby spots started to appear. They seem to be caused by tiny tiny white bugs on the undersides of leaves. I wish I could figure out what it was and how to treat it!

Spider mites live under leaves And can do damage fast but usually they also have fine webbing. do some research on them. They can spread easily in your home to other plants. I noticed the webbing on two of my plants and now those plants are quarantined while I treat them with neem oil and soap spray =(

I am having this issue with my Monstera Deliciosa.. I do not think it is normal because now it spread to most of my plants.. I also thought they were scales, but I do have scales on a different plant, and it doesn't look like that.. I saw white bugs, and they are not spider mites.. I had them before, and it is not the case 😥I don't know what they are; they look like thrips but smaller 🤦‍♀️ and kind of transparent in color.. I will be fumigating today and changing soil to all of my plants, trying to save them (+43 😓). The damage is spreading pretty fast!!

Gabriela, I am so sorry to read this, what a headache! Please please let us know if you find out what the pest is. My Monstera has grown A LOT since I wrote this post, but also have the brown scale-like spots. I'll snap some photos to share when I get home. I stopped scrapping them off, but have noticed they even grew on the propagated (now mature) second Monstera baby.

I have exactly the same problem and cannot find any information about those pests and how to treat it :( did you guys have any luck?

One of my monstera plants and my whole collection of philodendrons died after these started showing. They love philodendrons and monsteras but attack generally any plant. Because I couldn't find any information online how to get rid of them I tried scrubbing them off my plants and spray Neem oil soap and also used a natural insecticide when that didn't show any results. it didn't work 😕. So now I'm trying a chemical insecticide. And it seems to help let my plants survive...This thing what ever it is works similarly to thrips.. it sucks the life out of the plants. Hope some one in here could give some insight. 🙁

Hello! I noticed that when I tried scrubbing them off that thing grew bigger and stronger! :( I did find the pest, THRIPS :( they are so tiny!! almost transparent.. My Monstera is recovering, she looks good and has new leaves growing healthy but the thrips keep appearing (especially on the new leaves, if I open them a little before they unfurled there they are feasting on the new ones). It is extremely hard to see them, I change the soil and have been fumigating with neem oil almost every 3 days. I also removed the affected leaves, the ones that had a lot of that thing. I am alternating neem oil, potassic soap insecticide, and plaguifin that is an organic one too. It's been months of this fight! but at least she looks healthy and alive with the weird stuff still there and some thrips.. I might try chemicals, I bought it but haven't tried it yet. Good luck with your monsteras!.. I am sending some pictures of the new leaf and how it looks today.

Oh and here are the guilty ones!! it must be an effect or damage from them.. the THRIPS.. I took these pictures before fumigating properly. I haven't seen any adults in the last few days, only the little ones..

Adult

The red circles are the young ones, almost transparent.. the other ones in the middle are adults..

I hope this helps!! I am still fighting them but almost winning!! (I think!)

Good luck!

Hi! I couldn't find any info on this issue but stumbled across an article saying that this might be "corking", meaning that the stem becomes "woodier" to be able to support heaby leaves. So pretty much, the plan is ageing.

I recently read that there are thousands of different trips. I think that’s what these are. Mine are absolutely tiny white ones. Like the size of a grain of salt. I have been wiping the scaly parts in the leaves with rubbing alcohol. Seems like it wouldn’t be great for the plant but it absolutely helps. I also spray with neem fairly regularly. My plant is doing pretty well but I haven’t been able to eradicate them completely and it’s been almost 2 years! The tiny bugs have ended up on other plants throughout my house over that time but I have been able to rinse them off and spray the plants heavily w neem and they haven’t come back on others. They seem to love the Monstera though.

@Aarin mine were exactly the same and also impossible to get rid of. Finally I repoted my monstera, got rid of all the old soil and rinsed the leaves and roots thoroughly with shower before potting in a fresh soil. That was in the winter, no sign of any pests since 😊

Have you tried Pyrethrum liquid & spray?

One of the owner of plant shop kindly told me how she protects her plants with Pyrethrum.

She told me she mix Pyrethrum with water & dishwasher soap and use it to wash down/flush the soil in the pot (the way you watering your plant). And that's it, they will all die, including the eggs in soil or stems (she also spray her plants}.

As precaution, she also timer bug spray that also contains pyrethrum, it can be set to sprits regularly and run 24hrs/7days or 12hr/7days.

You may be able to find similar products where you are? (I'm in New Zealand).

https://www.yates.co.nz/products/garden-pest-control/yates-natures-way-natural-insect-spray-pyrethrum-concentrate/

This is some info I found online re: pyrethrum & thrips

https://homeguides.sfgate.com/pyrethrum-works-thrips-41906.html

I have the exact thing on my monstrea i removed it with my fingernail n rinse it with dish soap n perioxide n removed it from that soil dont see it anymore but one leaf has holes n brown spots i had to cut it off