When you find scale on your plants, getting rid of them can take some time – but it’s not impossible. I’ve successfully descaled my houseplants, and so can you.
In this post, you’ll learn how to identify them, where they come from, and the best natural and organic methods to get rid of them – FOR GOOD.
What Are Scale Insects?
Houseplant scale insects suck the sap out of the leaves and stems. This results in stunted or deformed leaf growth, yellowing of the leaves, brown pock marks, and possibly leaf drop.
You can find them almost anywhere on a plant, but they’ll usually be hanging out on the stems and leaf joints, and along the veins of the leaves.
You may also notice sticky leaves on the leaves, on the pot, or around the area where the plant is sitting.
This sticky substance is usually the best way to help with identification if you’re unsure. That’s because as the insects feed, they excrete a sticky residue, which is a common sign of an infestation.
What Do They Look Like?
Scale insects can be very difficult to see. Even if you do notice them, they appear more like a weird growth rather than a bug.
In fact, they look like small brown dots or bumps, and they don’t move. Eek! To me, they look like scabs on a plant (and that’s seriously what I thought they were the first time I saw them, haha).
They can be rounded, oval shaped, or flat, and can range in size from barely visible to large bumps. Their color can range anywhere from brown to tan to white.
Scale likes to cluster, so they are very noticeable once the population gets large. Like I said before, they don’t look like bugs so you probably won’t even notice them until your plant has become infested.
If the bugs on your houseplants are white and fuzzy and look more like mildew, those are mealybugs, and here’s how to get rid of them.
Their Life Cycle
Scale can reproduce very quickly. Their entire cycle takes about 7-10 weeks, and it has several stages.
It takes a few weeks for the eggs to hatch into nymphs (aka crawlers), and then another 6-9 weeks for the crawlers to mature into adults.
The nymphs can move around on a plant or migrate to surrounding ones. Once they find a good place to start feeding, and they mature into adults, they never move again.
The eggs and nymphs are tiny, so it’s easy to understand why most people will never know their houseplant has scale until the population has exploded.
Scale Damage On Plants
Scale insect damage can look like pock marks on plants like succulents and cacti, or it can be something as subtle as brown or yellow leaves.
Thankfully, the damage they cause is not as quick to occur or as devastating as it is with spider mites, but it can still look pretty bad.
If an infestation is left untreated, the plant could eventually die. Although it would take a long time, and a very large population for them to kill a mature indoor plant.
Related Post: How to Get Rid of Fungus Gnats In Houseplants Soil
Where Do Scale Bugs Come From?
When you discover scale on your indoor plant, the first question you’ll ask is where the heck did they come from? They’re actually very sneaky, and many times you will never figure out where they came from.
They can come from just about anywhere, so it’s easy to go crazy trying to figure it out. Here are 6 of the most common sources:
- Bringing home a new houseplant from the store
- Using contaminated potting soil
- Reusing a dirty plant pot
- Moving your indoor plants outside during the summer
- Bringing in fresh produce or cut flowers from the garden (or even from the grocery store)
- Leaving a window open – the crawlers are tiny, so they can get through the smallest openings
Read more about all of the places where houseplant bugs can come from here.
How To Get Rid Of Scale Insects On Houseplants
When you first find scale insects, you should isolate the infested plant and begin treatment immediately.
I don’t recommend using synthetic chemical pesticides. That’s because scale can build up a resistance to them, especially ones they are exposed to on a regular basis. Plus, in most stages of their life cycle, pesticides won’t penetrate their hard outer shell anyway.
Always use natural, organic methods instead. They are not only better for us and our family, they work to kill the bugs, and they can’t build up resistance to them.
You can learn even more about all-natural houseplant pest control remedies here.
Natural Treatment Methods
To help get you started, I’m sharing three of the best natural treatment methods. But before you begin, here are a few of my favorite tips:
- As you work on treating your plants you should check every crevice, especially around the leaf and stem joints and underneath all of the leaves.
- They like to hide, so be sure to check the plant from a bunch of different angles.
- Brush away a little dirt around the base of the stem to see if any are hiding there. It’s not uncommon to find them on the roots.
Rubbing Alcohol
You can use a cotton swab dipped in rubbing alcohol to kill and remove as many of the scale insects as possible. For the rubbing alcohol to be effective, it must come in direct contact with the bugs.
Some of the adults with the hardest outer shells might be stuck on there good. So you may need to pry some of them off with your fingernail.
This method works very well for small infestations. It also helps to eliminate as many of the large insects as you can so that you can gain the upper hand.
Homemade Insecticide Soap
You could buy organic insecticidal soap, or you can make your own homemade spray. My recipe is 1 teaspoon of mild liquid soap per 1 liter of water.
Either way, spray it directly on the bugs and on the leaves. If your plant is small, you can bring it to the sink or shower and wash the leaves, gently removing as many of the bugs as you can.
Keep in mind that some soaps can be damaging, so it’s best to test any type of spray on a couple leaves before you spray the entire plant.
Neem Oil
Neem oil is a natural insecticide, and it’s very effective for treating scale. An added bonus is that it has a residual effect to help with future prevention too.
It works best when you douse your plant, and continue using it until all signs of the bugs are gone. Learn more about neem oil and how to use it here.
More Tips For Getting Rid Of Scale On Plants
You can’t treat a plant once and expect to get rid of all of the scale, you need to be persistent. Keep checking on them a few times a week, and remove any new bugs that you see. Here are a few additional tips.
1. Replace the top layer of soil – Bugs can hide in the soil, so if a plant is plagued by recurring infestations, you could try removing the top inch and replacing it with fresh potting soil.
2. Clean surrounding area – Crawlers can leave the plant and then come back to infest it again later. So remove it from the area and clean any crevices where the pests could be hiding. Be sure to check around the outside lip and inside edges of the pot and drip tray, and the bottom of the pot for hiding insects.
3. Prune heavily infested leaves – Trim off the most heavily infested leaves and toss them into the trash (outside of your home). Never trim all the leaves off though.
4. Sanitize the pot – If you decide to repot a plant after treating it, be sure to sterilize the container before reusing it. Insects can hide on the edges, bottom, or the rim and easily infest the next plant. Scrub the pot with soapy water, or better yet, put it in the dishwasher to sterilize it.
5. Continue treating your plant – Use a neem oil regularly as a preventative measure until you are sure your plant is scale-free.
Getting rid of scale on your indoor plants can be challenging, but don’t give up! If you’re diligent, and follow my instructions and tips above, you will win the fight! Learn more by watching my web story.
If you’re struggling with bugs on your indoor plants, my Houseplant Pest Control eBook is for you! It will show you exactly how to get rid of bugs naturally, including identification, home remedies, how to keep them from EVER coming back, and much more. Download your copy today!
More About Houseplant Pests
- How To Debug Plants Before Bringing Them Indoors
- How To Get Rid Of Whiteflies On Indoor Plants
- How To Get Rid Of Bugs On Houseplants
- How To Get Rid Of Aphids On Houseplants
- How To Get Rid Of Thrips On Houseplants
How do you get rid of scale on houseplants? Share your tips in the comments below.
Phil kyryluk says
I bought a sago palm from Home Depot many years ago..It had scales…and now most of my plants do,especially all 5 of my spiders and all of my orchids. Dish soap helps but does not eliminate them.
Amy Andrychowicz says
Oh no, sorry to hear you’re fighting scale on your houseplants! Have you tried using neem oil? To get rid of a large infestation, you’ll need to be persistent and use a combo of methods. I recommend using rubbing alcohol on a cotton swab/cotton ball to clean off as many as you can see, then washing thee leaves with soapy water, rinsing them off, and dousing with neem oil (don’t rinse after that). Once your plants are clean, continue using rubbing alcohol to remove them as more bugs appear, and spray your plants with neem oil monthly until you no longer find anymore scale. Good luck!
Lea says
I’ve been treating my large lemon tree for scale for over a year with no signs of improvement. Several times now I have taken a week and did nothing but laboriously scrub every leaf and branch from the main trunk out starting low and working up and working my way around. It was EXHAUSTING… and although it would look better for a few weeks, within a month I would see new infestation spots starting. Neem oil hasn’t helped… NOTHING has helped…. I may call and arborist and have him skelatonize the poor thing once it’s done with with it’s current fruit harvest. For reference this tree is about 9-10 ft tall with a 14 ft circumstance…. It can’t really be moved as it’s planted into the floor of my greenhouse. I was wondering about heat treatment? Are scale tempature sensitive? I recently had a coworker bring home bedbugs from a vacation trip and they treated her house with heat to kill the insects….
Amy Andrychowicz says
Oh no, so sorry to hear that your plant is infested with scale, they can be very difficult to get rid of for sure – especially on such a large tree. I definitely stand by my recommendation for neem oil. It’s something that will take some time, as the bugs have to feed on the treated leaves before they will die, and there are usually MANY generations of scale present at one time. So you have to continue to treat the plant on a regular basis before you can get rid of them, it’s definitely not a one (or two or three) and done type of treatment. You can also try using neem oil as a systemic in addition to spraying it on the leaves. Here’s my tutorial on how to use neem oil to effectively get rid of bugs on plants to give you more details. But not matter what product(s)/technique(s) you choose to use, it will take time to get rid of a heavy scale infestation on a large plant, there’s no getting around that. 🙁 You could also try releasing ladybugs or some other type of predatory insect(s) into your greenhouse to help you out. That is a very common practice for greenhouse owners, even large-scale commercial ones do that. Good luck!
Yamile says
Do you use insecticidal soap weekly (whether DIY neem inseciticidal or the sprays you can purchase)?
Amy Andrychowicz says
Insecticidal soap has no residual effect, and will only kill the scale and their eggs on contact. So you should spray it weekly as long as you see bugs. On the other hand, neem oil does have a residual effect, so you can spray it on every few weeks.
Safi says
Can I use the Need Oil on a Naval Orange Tree? When it produces oranges I do not want them to be contaminated with chemicle.
Amy Andrychowicz says
Always check the package on the specific product you buy to make sure it’s safe to use on food crops.