Getting Rid of Houseplant Pests Naturally
This is the second in my two-part series on dealing with houseplant pests. If you missed the first part, you can learn about preventing houseplant pests here.
There are, of course, a multitude of pests that could be infesting your houseplants (cheery thought, isn’t it?), but I want to talk to you about the top four, and what you can do about them without resorting to chemicals. Let’s get to it, shall we?
What is Scale?
First, the bane of my existence: SCALE. This is what it looks like on the plant:
And here are some closeups (the lighter one is younger, the darker one is more mature):
Although it doesn’t look like it, scale is actually an insect. Only the very young juveniles are mobile, so the ones you see above have already matured to the point where they are immobile for the remainder of their lives (which were very short because I murdered the little buggers after I took the pictures).
They make little “houses” for themselves (if you look at the dark one above, you can see what I mean) and this protects them from pretty much everything. I picked up scale over 10 years ago from a plant I purchased, and I have never truly been able to eradicate it.
Scale has been, at least in my experience, the most difficult houseplant pest to get rid of entirely.
What types of plants does scale infest?
The thing is, though, scale does discriminate, it won’t impact every plant you have. In my house, it likes spider plants, aloe plants and citrus the best, although I know there can be others, too.
I have eradicated it on my spider plants and aloe plants, but my grapefruit tree, Spike, (read the story of my indoor grapefruit tree here) always seems to harbor just a few scale bugs that then spread over the course of the winter onto other plants.
In theory, if your plants aren’t touching, the scale can’t move from one to the other, but I believe sometimes they also drop onto a new plant if one overhangs the other. Just something to keep in mind.
Signs of Scale
So, first, how to find it? Well, you need to be vigilant in checking your plants. However, the first sign of scale is often not the scale itself, but the sticky secretion from the scale’s backside, called honeydew (it’s scale poop, ok?).
You’ll find this on the leaves or on the windowsill or even your floor.
Pro tip: If it gets on your hardwood floor, it’s a real bugger (pun intended) to clean up. Spray a paper towel with cleaner approved for your type of floor and cover the honeydew, then let it sit for a few minutes before wiping away.
Once you see the honeydew, start looking and you’ll either find scale, mealybugs, or aphids (read more about them below).
Once you find scale, you have several options.
What I typically try first is simply to squash the bugs. If you’re squeamish about squashing them by hand (you will get sticky but you can’t really tell it’s bug guts, LOL), you can use a paper towel or napkin soaked in alcohol, or even an alcohol-based wipe (like Lysol or Clorox). The alcohol won’t hurt your plant because it evaporates quickly, but will kill the scale.
Pro tip: Be sure to wash your hands immediately after completing your cleanup as you could potentially pass the scale to another plant yourself, which would be really, REALLY annoying!
When I had scale on my small lemon tree and just couldn’t get rid of it, I took the tree out of its pot (it was very small at the time, the size of a small houseplant), washed the tree’s roots with water, and cleaned every single leaf and stem with an alcohol wipe, then repotted it in a clean pot with clean soil.
It has not had scale since. I believe cleaning the roots and repotting in a fresh pot with clean soil was the trick, as I had tried cleaning the leaves and stems before and the scale had returned.
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You also have the option of using either insecticidal soap or a neem oil insecticide, as these are both organic options. With the neem, you don’t want to use it in your house, but should take the plant outside on a warm day or into a basement or garage.
I’ve found in the past that with either one, my plants don’t seem to be happy if I don’t rinse their leaves off after use, so I try not to use them except as a last resort.
What are Mealybugs?
Our second favorite houseplant pest is the MEALYBUG. Mealybugs are actually fuzzy, white scale bugs, but these little dudes can move.
I have never had mealybugs on my houseplants, but they are easy to spot as they look like white fuzzy dots on your plants. You can see a picture of them here.
Much like scale, you can remove mealybugs by wiping them off the plant with alcohol, but they like to hide in inaccessible parts of the plant (like leaves that haven’t unfurled yet) so you need to be really careful to find them all, and you’ll have to search regularly for several weeks to make sure you find them all.
I have also seen a recommendation to spray the plant with alcohol, but I would be leery of this and be sure to rinse the plant immediately afterwards to remove the alcohol. I’m just not sure what that much alcohol might do to the plant’s health and well-being.
Best Controls for Mealybugs
Unlike scale, which are difficult for predatory bugs to get at because of their protective coating, mealybugs are vulnerable to certain insects.
Both green lacewings and mealybug destroyers will take care of them. Whether or not you want to release either of these in your house is a personal choice. If you’d like lacewing eggs, you can get them here. If you’d rather the mealybug destroyers, you can get them here.
Keep in mind that if you release them in your house and the room doesn’t have a door, they aren’t necessarily going to stay right where you release them. However, they aren’t harmful to people or pets, so you might not mind.
What are Aphids?
Coming in at number three on our favorite houseplant pest list is the good old APHID.
Personally, I despise these creatures because they just seem to keep coming back over and over, no matter what I do. They’re very small, but here’s a closeup picture I took of them on my tropical milkweed:
How to Identify Aphids
Although the only aphids I’ve ever seen are yellow, they can be other colors, including white and greenish. These guys are very mobile, and they can fly, so having some on one plant almost guarantees that you’ll have them on others. In your outdoor garden, they’re controlled most often by green lacewings and ladybugs.
Indoor Control Options (Good bugs)
Again, either of these insects is suitable for release indoors if you have an infestation, as long as you don’t mind having lacewings or ladybugs flying around your house. Lacewing eggs can be purchased here and ladybugs can be purchased here.
Pro tip: Be sure to read the instructions the seller has on the sales page for shipping of live ladybugs. There are climate constraints and day of the week constraints to keep in mind when ordering. The seller also claims the ladybugs will kill scale. I’m not so sure about that, but it’s certainly worth a try.
Also, if you’ve never seen a ladybug larva before, check one out here so you don’t inadvertently kill them when you see them. They bear absolutely NO resemblance to ladybugs, are bigger than the adults and are kind of scary-looking (although they are harmless), so I don’t want you to accidentally murder the good guys.
Indoor Control Options (Organic Sprays)
If you’d rather not release bugs in your house, aphids can be killed by spraying the plant with strong, short bursts of water (from a hose or sink sprayer). Once you’ve done that, you can manually squash any left on the plant. You will need to repeat this operation every few days for a month or more to make sure you’ve gotten them all.
Another option, again, is either horticultural (neem) oil or insecticidal soap. I have also seen hot pepper wax recommended, but I’ve never used it personally so can’t speak to how well it works.
What are Whiteflies?
Last, but certainly not least on our Top 4 list is the WHITEFLY.
If you have houseplants, you almost certainly have whiteflies. They are those little bugs that fly up in a swarm when you disturb a plant. They look like fruit flies, but infest plants, not fruit.
I always have them by the end of the winter, although for me, they haven’t really been a problem. I don’t seem to get them until about April, and since most of my houseplants go outside sometime in May, I haven’t had to treat for them.
I haven’t noticed any effects from them, although they can damage and weaken plants just as our other friends can.
Whitefly Control Options
Again, most of the remedies listed above are effective on them, including green lacewings, ladybugs, insecticidal soap and neem oil.
Another option you have with these guys is sticky traps. You may have seen yellow pieces of paper hanging in greenhouses before. Now you know what they are!
Because whiteflies are attracted to the color yellow, you can place yellow sticky traps close to your infested plants to help trap the adults. You will still need to treat with either soap or oil for the larvae, but the traps will capture the adults.
Pro tip: Don’t use the traps in conjunction with either ladybugs or lacewings as you may inadvertently catch them as well.
Companion Herbs for Pest Control
One last point I’d like to make is that there are certain plants that repel insect pests. Obviously, being that we’re discussing houseplants, you’ll be limited as to what you can do, but aphids are said to be repelled by dill.
Who doesn’t love the taste and smell of fresh dill (except apparently aphids), so why not grow some?
Many pests, including aphids, are also repelled by catnip. I’m pretty sure having catnip plants in my house with my 5 cats would not be such a good idea, but if you don’t have cats, it’s an option, as it is an attractive plant.
I hope you’ve learned something new and helpful today. Please feel free to leave me some comment love and any questions you might have.
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- Preventing Houseplant Pests
- My Indoor Grapefruit Tree
- Growing Healthy African Violets
- Splitting and Propagating African Violets
- Growing Indoor Herbs
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