What Are These Bugs on My Houseplant, and How Do I Get Rid of Them?
What Are These Bugs on My Houseplant, and How Do I Get Rid of Them?
We talk about pests quite a bit during my Lives, and one of the biggest things I want people to understand is that you need to have a pest regimen. Whether you've got five plants or fifty, you need some kind of routine for checking them and managing bugs.
Because here's what happens. Somebody finds a bug, gets rid of it, and thinks the problem is taken care of. A week later, they're finding more.
Well, those bugs have been reproducing, and there's probably a whole lot more happening on that plant than what you can see crawling around.
So let's talk about what I would do when I find pests and how understanding their life cycles can help us get those populations under control.
First, Get That Plant Into Quarantine
The first thing I recommend when you find an active infestation is getting that plant away from the rest of your collection.
And I actually like the idea of using a closet for quarantine.
Think about it. If you've got thrips flying around a large room, that's a whole lot of space for those little bugs to disappear into. Now you're trying to figure out where they're going and whether they've made their way to your other plants.
If you've got a closet where you can set up some plant lighting, you've created a much smaller area to work in. You can keep an eye on the plant, inspect the surrounding space, and have a better chance of finding those insects.
You want enough light to support the plant and proper ventilation so the space doesn't become too warm or stagnant. We're trying to contain the pest problem while keeping the plant growing.
If you're treating with alcohol, I would take the plant into a well-ventilated area with the plant lights off, then let everything dry completely before returning it to quarantine.
I like having a dedicated area because it makes the whole process easier to manage, especially when you're dealing with insects that can fly.
What Kind of Bug Are We Looking At?
Let's get familiar with a few of the common ones.
Spider mites are extremely small, and you'll often notice little pale speckles on your leaves where they've been feeding. You may also find fine webbing, especially when the population has grown. Alocasia are one of the plants where I see people dealing with them quite a bit.
Thrips are tiny, slender insects. They can leave silvery damage, little black specks, and new leaves that come in looking distorted. Their young are even smaller than the adults, so you've really got to pay attention when you're checking the foliage.
Mealybugs have that white, cottony appearance, and they love tucking themselves into the spaces where leaves meet stems.
Scale can look like little brown or tan bumps attached to a stem or leaf, while aphids often gather around soft, new growth.
When I'm checking plants, I put my glasses on and start turning those leaves over. I'm looking underneath them, around the stems, and down inside that new growth.
And if you're finding little flies around your soil, those may be fungus gnats. I call those moisture bugs, and we've already got a separate article explaining how to manage them.
Why Do I Keep Getting Fungus Gnats?
You Need to Find Their Babies
This is probably one of the most important things I teach about pests.
When somebody finds a larger bug crawling around, that's usually the one they're focused on getting rid of.
But think about what that insect may have already been doing. It could have been laying eggs, and there may already be another generation developing on your plant.
That's what I really want you to start looking for.
Take thrips, for example. Many species lay their eggs right inside the plant tissue. Those eggs hatch, and the young begin feeding. Depending on the species, other stages of their development may happen in the soil or protected spaces around the plant.
Spider mites lay eggs on the plant, often underneath the leaves. Mealybugs and scale have their own reproductive cycles.
Those adult insects are still important because they can continue reproducing. But when you're only looking for the bigger bugs, you can miss all those younger ones that are getting ready to take their place.
And that's how you end up treating a plant, thinking everything is wonderful, and finding another group of bugs several days later.
Learn where your particular pest lays its eggs, what the young look like, and where they're likely to be hiding.
You want to interrupt that life cycle so the next generation doesn't keep building the population.
What's Your Regular Pest Regimen?
This is something I want everybody to think about before they've got an infestation.
What's your long-term plan for managing pests?
At Rooted, I use beneficial insects as part of my routine, generally introducing them monthly. There are different beneficial insects for different pests, and some target specific stages of their development.
Another option is using a systemic insecticide. Depending on the product, the plant takes up an active ingredient that affects certain insects when they feed. But systemics have different uses, and they're not effective against every pest. You need to know which insects your particular product controls and follow its directions.
If you're using beneficial insects, you also need to consider what chemical treatments you're using because some of those products can harm the beneficials.
I keep those approaches separate and plan them carefully.
The important thing is having a regimen you understand and can maintain. Something that makes sense for the plants you're growing and the pests you're trying to manage.
And What's Your Contact-Treatment Plan?
Now let's talk about what you're going to do when you actually find bugs.
At Rooted, I use 70% isopropyl alcohol as part of my pest-management routine. I generally work on a weekly preventive schedule, and when I'm dealing with an active infestation that I'm treating with alcohol, I may treat daily for four to seven days initially.
There are other contact treatments available, including insecticidal soaps and horticultural oils. Different treatments work on different pests, so it's important to know what you're using.
The thing I want you to understand about contact treatments is that you have to reach the bugs.
If you've got mealybugs tucked down between the stems and you're only treating the tops of your leaves, you've probably missed quite a few.
The same thing goes for spider mites hiding underneath the foliage.
With alcohol, I recommend testing a small area first because some plants have more sensitive foliage. I keep my plant lights off during treatment and until everything has completely evaporated.
And if you're using beneficial insects, you need to plan your contact treatments around them, too.
Your long-term regimen and your contact-treatment plan should work together. You want to know what you're using, why you're using it, and how it affects the insects you're trying to control.
Consistency Makes a Tremendous Difference
You can have a wonderful pest regimen, but you've got to be consistent.
Maybe you've introduced beneficial insects, but you're not checking whether they're keeping up with the pest population. Maybe you're using a systemic product, but you're missing the timing in the directions. Or you've treated a plant a couple of times, everything looks good, and you quit checking it.
Meanwhile, another generation may be developing.
This is why I encourage people to spend time with their plants. When you're watering, turn those leaves over. Look around the stems and inside the new growth. Get familiar with what you're seeing.
And when you're treating an infestation, keep checking even after you've stopped finding adults.
Those little insects can reproduce pretty quickly under the right conditions. Learning their life cycles and staying consistent gives you a much better chance of keeping those populations under control.
How Do You Know You're Making Progress?
Let's say you've got an Alocasia that had spider mites. You've moved it into quarantine, followed your treatment plan, and now you're not finding any mites when you check underneath the leaves.
And you've got a beautiful new leaf coming in.
That's something I want you to pay attention to.
Is that new leaf developing without fresh feeding damage? Are you still finding bugs anywhere on the plant? Are the next leaves coming in healthy?
Those observations help you understand whether you're making progress.
And remember what I always tell people about their older leaves. If those leaves have some damage but still have healthy green tissue, I like keeping them. They're a record of what the plant has been through.
You can compare those older leaves with the new ones and see how the plant is responding.
Eventually, those older leaves will naturally age off, and you'll have all that beautiful new growth.
But continue checking for live pests even when everything looks wonderful. Healthy new leaves are encouraging, and finding fewer insects over time tells us whether we're actually getting that population under control.
Keep Learning With Rooted
There's quite a bit to learn about houseplant pests, especially when you start understanding how they reproduce and where their young are developing.
That's why I wrote The Rooted Guide to Houseplant Pests.
It's a 192-page guide where I go much deeper into the different pests, their life cycles, where they lay their eggs, beneficial insects, systemics, contact treatments, and how to build a pest regimen that works for your collection.
I want people to understand what they're looking for and why they're doing something. Once you understand the insects you're dealing with, you'll feel a whole lot more comfortable managing them.
