No one likes seeing tiny black bugs crawling around on their plants – especially when those plants are kept inside.
You honestly have to wonder how it is that these things found their way inside your house (in my case all the way to my bedroom, far away from any doors or windows that are regularly opened) and onto your plants.
The most common tiny black bug that you will find around a plant is the fungus gnat. They lay their larvae in your potting soil and fly around your plant, sometimes landing on its leaves. Aphids, spider mites, and thrips are also tiny bugs and may be what you’re seeing. Proper identification is key to controlling them.
Let’s take a closer look at how to figure out what is bugging your plants and how to get rid of it. Later in the article, we’ll also talk about how to prevent bringing these bugs inside and creating new infestations.
Identifying & Treating Common Houseplant Pests
First, let’s take a look at what the most common houseplant bugs are that are small and black (or a darkish color, at least) and try to figure out which one is affecting your plants.
Fungus Gnats
Fungus gnats are going to be by far the most common tiny black bug you’ll see on your indoor houseplants. (They are also called soil gnats sometimes.)
They are pretty easy to identify – being small gnats that hang on and fly around the soil in your plant pot. They typically show up if you have potting soil that stays moist all the time.
(For example if you have a plant in a wick pot.)
As a larvae, they are a tiny, clear worm that lives in the soil in your pot and is quite difficult to spot. (Photo included above.)
Luckily, they don’t cause any actual damage to your plants, and they only feed off of the fungus in your soil, but they can still be quite annoying.
Identification: You can tell if you have fungus gnats because you’ll have a bunch of small black flies hanging out on your potting soil, and when you disturb the soil they will all fly off.
How to Get Rid of Fungus Gnats:
The easiest way of getting rid of fungus gnats is to remove the fungus that they feed on. This fungus depends on the soil being damp, so if you stop watering your plant so often and let the soil dry out, they will eventually go away.
You can supplement this by adding some yellow sticky pads to your pot, which will capture and kill the adult flies so they can’t lay more eggs.
A natural insecticide that will deal with the adults is neem oil, but this generally won’t kill any of the larvae that aren’t already on the surface of the soil, so it’s generally not recommended.
If you are willing to go with a harsher insecticide, you can get imidacloprid in granular form that you can sprinkle onto your potting soil that will kill the larvae when watered into your soil. Imidacloprid is generally safe for dogs and humans (but not cats) in the amounts that you would be using here, and it is used in chewable flea treatments for dogs.
Aphids
Aphids are one of the biggest banes of plants everywhere. Next to fungus gnats, they’re the most likely pest you’re likely to run into on your houseplants, and unlike fungus gnats – they can cause damage to your plants.
Aphids are tiny, teardrop shaped bugs (with or without wings) that come in a number of colors, including red, yellow, green, black, and white, with a tiny straw sticking out of their face that they use to drink the sap from your plant.
Then they breed, creating tiny white nymphs that themselves drink your plants’ sap until your plant can’t produce enough energy to keep itself alive because of all of the tiny vampires feeding off of it.
Identification: Look for tiny, tear drop shaped bugs clustering around new growth, flower bugs, or the under sides of your plant’s leaves.
Getting Rid of Aphids
Getting rid of aphids can be relatively easy when dealing with indoor plants. The easiest way to get rid of them if you don’t have a huge infestation is to just hit them with a garden hose or shower head sprayer (if you have one that’s on a hose) and blast them off of your plants.
If you have a big infestation, you can spray your plant down with neem oil or a mix of 1 part rubbing alcohol to 5 parts distilled water to kill them. (Normal water will work but may leave mineral stains on dark leaves.)
If you don’t hit every part of the plant, you may have to do a second treatment to get any stragglers.
Spider Mites
Spider mites are a tiny bug that may look like a collection dark (or sometimes yellow, red, etc) specs on your plants or – more likely – on spider webs connecting your plant’s leaves.
A bad infestation can wrap plants in a cocoon of spider silk, which can be quite distressing.
Even though it looks bad, you don’t need to throw the plant away. If you’re willing to do a bit of work, you can clean them off and save your plants.
Identification: Look for spider webs on your plants with small black specs living in the webbing.
Getting Rid of Spider Mites
Getting rid of spider mites may take a bit of work, depending on how bad of an infestation you have.
The first thing you’ll want to do is clean the webs off of your plant – and the spider mites on those webs.
If you don’t have a bad infestation, something like a piece of toilet paper or Kleenex will work fine. With a larger infestation, where your plant is covered by a large amount of webbing, something like a swiffer duster may work better.
Just use whatever is readily available that looks like it might work.
Once your plant looks relatively clean, you can rinse it off with water to spray any mites you may have missed off of the leaves. Pay attention to the undersides of leaves.
Afterwards, you can spray the plant down with neem oil to kill any stragglers. You may have to repeat this treatment every few weeks until the infestation stops. Keep in mind spider mites hide in the soil over winter, so if it gets cold where you are you may have to repeat the treatment when it warms up or use a soil based pesticide as mentioned above with fungus gnats.
Thrips
Thrips are a tiny bug that can be hard to spot until you’ve got a big population of them, and at that point, you’ve got a big problem.
They can cause a lot of damage to your plant – curled new leaves, silvery-white or brown streaks and patches on existing leaves – and this won’t heal. You’ll have to prune the existing leaves and wait for new growth or live with the damage.
Because of this, it’s important to identify and deal with them quickly.
I’ve included some photos of thrip damage so you know what to look for.
Identification: Small bugs that are thin and long with a pointy tail. May have wings, but generally won’t fly. They may hop. Nymphs may be green or yellow and without wings.
Getting Rid of Thrips
The first step you should take to get rid of thrips is to prune and remove any damaged parts of the plant. This will remove the thrips along with the leaves and leave you with a much smaller problem to deal with.
You can spray the plant down with either neem oil, insecticidal soap, or a mix of 1 part rubbing alcohol to 5 parts distilled water to kill the ones that are left. Spray liberally, since you want to get rid of any that are left.
Watch your plant closely for the next few weeks to look for any that may have survived, and re-treat if necessary.
Preventing New Infestations
Now that we’ve talked about the most common types of tiny black bugs on your plants and how to get rid of the ones that you already have, let’s talk about where they come from and how to stop them from getting into your plants in the future.
Bringing Infested Plants Inside
The most common way of bringing pests into your house is by bringing infested plants inside. Once the pests are inside, they can spread to your other, healthy plants and infest them as well.
This can happen a couple of ways.
- Buying a new plant from a garden center.
- Bringing a plant outside and then back inside.
In these cases, you need to examine the plant closely before you bring it indoors to make sure no bugs are on it. If you’ve purchased it from a garden center, you may want to quarantine it for a week or two and observe it to make sure there are no bugs before putting in near your other plants.
Putting Plants Near Doors & Windows
If your plants are next to your doors – or next to windows without screens – bugs may fly in and find their way to your plants. This is especially the case for mobile bugs like fungus gnats. In this case, there may be limited things you can do other than move your plants farther away from the door, get a screen for your window, and be mindful of how long you’re leaving the door opened for.
This is not as big a concern as taking your plant outside for sun and leaving it there for an extended period, however.
Conclusion
If you’ve got tiny black bugs on your plants, there’s no need to worry. With a little bit of work you can identify and remove what’s bugging you and keep your plant healthy. Finding out how they got in to begin with can be a bit harder, but it just comes down to thinking like a bug.