Follow these tips to get rid of aphids on your houseplants … for good!
Aphids can be destructive pests on houseplants. Some aphids carry viruses from plant to plant. They also excrete sugary honeydew on the plant, which in turn leads to black sooty mold. They can warp leaves and make your houseplant stop growing.
Are you ready to get rid of the aphids overrunning your houseplants?
Read on for 10 ways to wipe out aphids so they never return!
Jump to:
- What are Aphids?
- The Three Important Principles of Pest Control
- 10 Ways to Kill Off Aphids on Houseplants
- Quarantine Aphid-Infested Houseplants
- Remove Badly Infested Plant Parts
- Squish Them!
- Give All Your Plants a Spa Day
- Practice Good Plant Hygiene
- Put Up Yellow Sticky Traps
- Switch to a Slow-Release Fertilizer Low in Nitrogen
- Spray Rubbing Alcohol
- Spray Neem Oil
- Use Vegetable Oil Spray
- Once the Aphids are Gone
What are Aphids?
They are small, soft-bodied, pear-shaped insects in colors such as green, yellow, black, and red. Aphids on houseplants can be winged or wingless.
These tiny insects have piercing-sucking mouthparts – that is, their mouth is a straw. Aphids poke their mouthparts into a plant leaf and inject enzymes and toxins into the plant cells. This liquifies cell walls and proteins into a tasty (for them) brew. Then aphids can easily suck the liquid out of the plant.
Aphids are visible on all parts of houseplants, especially on tender new growth. They especially like to gather on buds, stems, and the undersides of leaves. Sometimes, they can even be found on the roots. Aphids also leave behind the white exoskeletons they shed, as well as sticky honeydew and black sooty mold that grows on the honeydew.
Aphids are common worldwide, and their many different species attack many different plants.
Signs of Aphids and Aphid Damage
- Small drops of a sticky, sugary substance appear on the leaves.
- Tiny insects gather under leaves and cluster on new growth.
- New foliage looks crinkled or is stunted.
- Tiny white insect casings lying discarded on the plant.
Read more: Proven Ways to Kill Mealybugs on Houseplants
How Do Aphids Spread So Quickly?
A few aphids aren’t a problem – until they start multiplying.
Aphid eggs are laid on leaf buds and in bark crevices. Aphid nymphs hatch from the eggs and grow into full-grown adults in about one week.
Then, over the next two weeks, these females will birth about 50 to 100 live nymphs. These grow to maturity in one week, and then they start birthing live young.
Did you know that females can give birth to baby aphids without mating? There’s no waiting around with these guys!
Eventually, some of these new aphids will grow wings and fly to new plants, where they start popping out young aphids of their own. Good times!
Read more: How to Keep Aphids Out of Your Organic Garden (10 Ways)
The Three Important Principles of Pest Control
So, aphids reproduce insanely fast, but you still have the upper hand if you know the three important principles of pest control. This applies to houseplants as well as outdoor plants.
- The first important thing in aphid control is using several different control methods at the same time. Hit the aphids from all sides so they can’t recover.
- Second, keep hitting the aphids with these different control methods for a full month or two. You’ve got to be sure you’ve knocked down all the aphids. Otherwise, a lone female will climb out from under a leaf and start birthing aphid babies left and right – and you’re right back to square one.
- Finally, don’t rest after the aphids are eradicated. Keep checking the plant over the next couple of months to make sure the aphids stay gone. This way, if that lone female shows up, she gets squished before she even gets started!
10 Ways to Kill Off Aphids on Houseplants
For best results, go through the list in order. A lot of folks start by reaching for the insecticide, but that actually should be used after these beginning steps.
Quarantine Aphid-Infested Houseplants
The first step always is to get the affected houseplant away from the others. Keep all the trouble on one plant only! Don’t let it spread to the others!
Remove Badly Infested Plant Parts
If a leaf or stem on your houseplant is badly infested, cut it off. You can cut back a houseplant by a third or by half at the very most and get the aphid-infested foliage out of the house. This gets rid of a big chunk of the aphid population and gives you a smaller area to focus your control efforts on.
Squish Them!
This is icky, so feel free to wear disposable medical gloves to squish any aphids on the plant. Get the backs and tops of the leaves and the sides of the stems, and go over the plant, top to bottom. Aphids can develop a resistance to chemicals, but they never develop a resistance to being squished.
Give All Your Plants a Spa Day
Put the infested plants in the sink and use the spray nozzle to blast the remaining aphids off the plants. Splash soapy water on the leaves and clean them off, top and bottom. Then, rinse everything off with the spray nozzle. Make sure to spray into the joists where the leaves meet the stem, along with any other nooks and crannies on your plant that might hide renegade aphids. Leave the plants in the sink to dry off and drain while you do the next step.
Practice Good Plant Hygiene
Clean up your houseplant area. Wash off the containers they sit in, wipe down the area where they live, and throw away any dead leaves or plant bits that are lying around. As the weeks go by, keep up with clipping off dead leaves and flowers and throwing them into the compost pile outdoors (or in your indoor compost box). This gets rid of any extra insects that might be lurking around, trying to make a comeback.
Give your other plants a spa day as well before returning them to the cleaned-up area. But keep your aphid houseplant in quarantine for a month.
Read more: How to Kill Aphids and Soil Gnats with Homemade Vinegar Spray
Put Up Yellow Sticky Traps
Flying aphids and other insects (like the endlessly annoying fungus gnats) like landing on yellow things for some reason. If the yellow thing they alight on is a sticky trap, that’s a total win for you. Sticky traps are cheap and last for a little while.
These can act as a deterrent for cats or dogs that like to nose around the plants. If your cat comes streaking out of the plant room with a yellow sticky trap stuck to his face, a little vegetable oil will unstick it. Then, your cat will have learned a valuable lesson. Or not, knowing how cats are.
Switch to a Slow-Release Fertilizer Low in Nitrogen
Aphids are drawn to soft, tender leaves because they are juicier than old, tough leaves. Excessive nitrogen causes too much soft green growth. Instead, use a slow-release fertilizer like Osmocote. These release small amounts of fertilizer, which in turn causes the plant to slow down on producing tender green growth.
A quick note on pest control sprays: The next three options are chemical controls (though environmentally friendly). But they must be used separately.
Spray the rubbing alcohol once a week. Then, let a week pass before switching to neem or vegetable oil (if the infestation is still large enough to justify it).
Always read and follow label instructions!
Spray Rubbing Alcohol
Rubbing alcohol, or 70% isopropyl alcohol, is surprisingly effective against pests in general. It burns through the waxy protective layer on the aphids. The alcohol evaporates quickly, leaving no residue behind. The fumes also kill insects. In Entomology class, we used a cotton ball with rubbing alcohol in a pint mason jar to kill insect specimens for our collections.)
Before using this method, test the alcohol spray on a small part of the plant first. Rubbing alcohol will burn tender plants like oxalis and some succulents. Keep the plant away from the sun while the leaves are wet.
Use only 70% isopropyl alcohol. 90% will burn the heck out of everything it touches.
Spray once a week to kill off any surviving or newly hatched/birthed aphids.
Spray Neem Oil
Oils block the air holes (aka the spiracles) that insects breathe through, killing them. Sometimes, the oil also interacts with the fatty acids in the insect’s body, throwing off their metabolism and slowing insect growth. It can also disrupt the aphid’s ability to feed, which is good news for houseplants.
Water the plants before spraying with oil, as dry plants might not respond well to these sprays. Again, as with the rubbing alcohol, spray it on a leaf and see if there’s any reaction before spraying the whole plant. Some houseplants can be sensitive to oil sprays.
Neem oil needs to cover the pest in order to kill it, so spray both sides of the leaves and stems well. Shake the sprayer tank to keep the oil mixed with the water. Be sure to spray where oil won’t get on the walls or nearby furniture.
Use Vegetable Oil Spray
Vegetable oil can be a good insecticide. Soybean oil, which is most common, gives fair to good control of insects (also mites). For best results, use cottonseed oil – this has better results against aphids and other insects.
Vegetable oil spray is a DIY insecticide, but this recipe is extremely eco-friendly. It can be used indoors and outdoors on aphids and other pests, and it’s not going to harm anybody that’s not an insect. If you grow vegetables or lettuce, you can spray them with this vegetable oil spray up to the day of harvest.
What you need:
- 2 cups vegetable oil
- ½ cup liquid castile soap
- A container with a tight lid (like a Rubbermaid container or a wide-necked jar)
- Spray bottle or 1-quart sprayer
To make vegetable oil spray:
- Put 2 cups of vegetable oil in the container.
- Add ½ cup soap.
- Put the lid on tightly.
- Shake it until the solution turns white and stays white.
This is the concentrated stuff, so don’t spray this on your plants! It must be diluted with water.
To use the vegetable oil spray:
- Put 1 quart, or 1 liter, of water in your sprayer.
- Shake the oil concentrate container before opening it.
- Add 2 teaspoons of the liquid vegetable oil concentrate to the water.
- Close the sprayer and shake.
- Spray on the affected plants, shaking the sprayer occasionally to keep the solution mixed.
Store the vegetable oil concentrate in a cool, dark place. It stays good for about 3 to 6 months. If it starts smelling rancid, like oil that’s been sitting around too long, throw it out and make a new batch.
Once the Aphids are Gone
Once the houseplant is aphid-free, keep it in quarantine and monitor it for another month or two. Squish often, spray the houseplant once a week if necessary and give it a bath every month. When the houseplant is aphid-free for a full month, go ahead and return it to the plant table.
Aphids are annoying, but you can turn the tables on a big infestation by targeting them with simple, mostly all-natural gardening solutions.
As always, remember that multiple attacks with several different control methods at the same time are your best bet for controlling these tiny pests and their crazy-fast reproduction rates.
Sometimes, it takes a little while to hit upon the best combination of control methods to put a stop to them. Your aphid-free houseplants will love the results.
Read more: How to Make Homemade Ant-Repellant Cleaning Spray
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