How to Get Rid of Aphids on Houseplants and Gardens

Aphids, also known as plant lice, are small green, yellow, red, pink, brown, grey or black colored insects (1-7mm in size) from the Aphidae family which consists of over 5000 species and are among the top 10 most common houseplant pests. They are found in gardens and on houseplants worldwide, with the greatest diversity in northern climates and the least in tropical regions. Their reproductive cycle is temperature-dependent, and in the warmer months they can develop from a nymph to maturity in as little as 8 days. 

Fun fact: Aphids come in a variety of colors because most aphid species are specialized to certain plant types, so they have adapted to better camouflage themselves from their natural predators, like ladybugs, other insects, or birds. 

They live in colonies on plants, where they use their stylets (mouth parts) to suck plant sap (sugars) for food from the foliage, stems, flowers or even roots. They then secrete honeydew as a byproduct which can attract ants and lead to sooty mold buildup. 

While sucking sap is damaging to the plant, aphids might cause long-term additional damage and transmit viruses while feeding just like a mosquito can transmit disease among humans and animals. Aphids are a known vector (transmitter) of over 275 plant viruses around the world, transmitting 50% of all insect-vectored viruses. Plants infected by viruses may have mottled, yellowed or curled leaves, misshapen fruits, or stunted growth. 

So what can you do to get rid of an infestation on your houseplants, which, if left unchecked, can spread rapidly through all your plants? Simple, first you want to identify that it is an aphid infestation, then target the aphids so they cannot survive. Below you’ll learn how to do both. 

These small, pear-shaped insects have two antennae, long stylets (mouthparts), and two tubes that extend backward from their abdomens called cornicles, which are unique to aphids making their identification easy. Adult aphids can be winged or wingless, although all immature aphids (called nymphs) lack wings.

The wings allow them to travel from plant to plant outside, or to fly into your windows or through screens and land on your houseplants to feed and reproduce. This is why you should regularly inspect all your plants, even if they’re grown strictly indoors. 

Aphids live in colonies so an infestation is often visible to the naked eye. Make sure to check underneath leaves and along plant stems for large groups of the bugs. You will also see or feel the sticky honeydew residue, often with the molted exoskeletons stuck inside. 

Pro-Tip: In the spring and summer, inspect your plants at least twice a week as this is when aphids reproduce more rapidly compared to other months. 

To identify if a bug is an Aphid, look for:

• Egg or pear shaped bodies

• 1-7 mm in size

• Green, yellow, red, pink, brown, grey or black colored body

• 2 antenna

• 2 cornicles extending backwards from the abdomen

• Molted exoskeletons

• May be winged or wingless

Fun fact: Some aphid species like the woolly beech aphid and woolly aphid can cover themselves in a white waxy substance, which can cause them to be confused with scaly insects and mealybugs. Check for cornicles to ensure you’re looking at an aphid. 

Other signs of an aphid infestation include yellowing or curling of the leaves as they suck the sap out of the plants. Sap is your plant's energy source, so uncontrolled aphid feeding will weaken your plants as the plant loses the energy to maintain its leaves and it may eventually die.

An increase in ants can also signal an infestation as they are attracted to honeydew and will eat aphids' natural predators including ladybugs and lacewings. By killing and eating the predators ants can rely on more honeydew production.

Pro-tip: If you see ants trailing up your tree trunks, the aphids may be living high up in the branches. Water sensitive paper can be used to measure the amount of honeydew dripping from the tree to determine the size of the aphid population. 

After identifying affected plants, isolate them to prevent aphids from continuing to travel and feed on your collection. 

Pro-Tip: Move affected plants as gently as possible so the aphids aren’t tempted to take flight to a more stable home. 

Once isolated, here are five strategies to treat plants and get rid of an active aphid infestation:

• Removing with Water and Wiping them off

• Dunk or spray the plant in soap

• Neem oil

• Use an insecticide

• Introduce natural predators (outdoors)

Pro-tip: Put on gardening gloves before trying any of the methods below and wash them thoroughly after. 

The easiest method for minor infestations is to rinse your plants with a hose or under a sink sprayer, then wipe off any stragglers with a clean cloth. Aphids are typically not tightly bound to the plants they feed on and can be easily dislodged. 

1. Take the plant to a sink with a medium-strong spray setting or to your outside hose spigot and thoroughly rinse it, making sure to get the stems, undersides of leaves, and any other areas where aphids may be hiding. The water pressure should dislodge any aphids without harming the plant, but extra care should be taken with young plants. 

2. With a clean and damp cloth wipe off all visible remaining insects making sure to get the tops and undersides of the leaves, the stems, and any other areas. 

   1. You can also knock the insects off with your gloved hand, just make sure they die or fall on sticky paper so they can’t infest a new plant. 

3.  Clean the cloth very well or throw it out, do not leave it near the plants so any living aphids do not re-congregate on your plants.

4. Give the plants a blast of the hose every other day until the infestation is under control.

For mild to moderate infestations, you can use a dilution of insecticidal soap in a spray bottle or a few tablespoons of a pure liquid soap without degreasers or moisturizers (like castille) mixed with water in a spray bottle or bucket (you want to create a 1-2% solution). 

The soap will coat the aphids and break down their soft bodies and exoskeleton, causing them to suffocate and die. Soaps have an added bonus of being safe for indoor application and usually non-toxic. Check the labels before using this, and make sure it is kid and pet safe if you have little ones in your home.

1. Pre-rinse off your plant with a hose with a medium-strong spray or wipe any aphids you find with a damp cloth and throw the cloth away or wash it thoroughly.

2. Mix the insecticidal soap or liquid soap with water according to the instructions, and spray all visible aphids or eggs, including the tops and undersides of leaves, stems, flowers, and roots. 

   1. If you mixed the solution into a bucket or sink, dunk your plant and gently swish it in the water to ensure it, and any aphids on the plant, are covered in the soap. 

3. This only works if the soap covers the aphids, so it may need to be repeated every 5-7 days if any insects are missed until the infestation is cured. 

Pro-tip: Avoid this method on plants that are water stressed, as in over or under-watered, or in environments greater than 90F (32C) as the soaps may cause phytotoxic effects on your foliage when combined with the higher temperatures. 

Neem and horticulture oils kill aphids at all life stages suffocating them and neem oil in particular has azadirachtin. If azadirachtin is ingested by the aphids it can make the plants taste bad to the point where they may starve to death, it can prevent nymphs from molting and becoming mature, and cause adult females to become infertile.

1. Pre-rinse off your plant with a hose with a medium-strong spray or wipe any aphids you find with a damp cloth and throw the cloth away or wash it thoroughly.

2. Mix the oil with water following the instructions (normally a 1 part to 1 part ratio) you find on the bottle and spray the entire plant weekly for three to four weeks or until you no longer see aphids

3. Repeat weekly until the infestation is gone.

For infestations that are not responding to gentler methods, try a plant-safe insecticide. 

You will need:

• One bottle of plant safe insecticide

• A spray bottle

• A clean cloth

To treat the Aphid infestation:

1. Do a preliminary rinse of the infestation, then wipe off as many aphids as possible with a clean cloth while changing clothes and rinsing them to make sure you don’t accidentally spread the aphids.

2. Mix the insecticide following the instructions on the container.

3. Apply the mixture to all affected areas of the plant, including the undersides, and let it dry.

4. In 10 to 14 days, or whatever the recommendation on the bottle is, mix another batch of the insecticide and pour it in a spray bottle to treat the plant again. This may be done a few times to ensure the infestation is gone.

The catch here is that the insecticide will not just kill off aphids, but also other insects. Be sure to keep treated plants out of reach of animals and small children. 

For severe or repeated outdoor and garden infestations, you may want to try introducing predators that will eat or kill the aphids without damaging the other plants or local ecosystem. 

Aphid populations in nature are controlled by their predators, so when other means don’t work it’s best to revert back to letting the laws of nature work their magic, and some predators are insects we enjoy seeing like ladybugs. Once the infestation is taken care of, the introduced predators often move on to other areas or die off. 

Aphid predators include:

• Ladybugs

• Green Lacewings

• Aphidius ervi, Aphidius colemani, and Aphelinus abdominalis (we do not recommend these as they are wasps)

• Aphidoletes aphidimyza (Predatory midge larvae)

• Hoverfly larvae

Squishing a few aphids (with gloved hands) will help attract the predators to the plant by releasing chemicals into the air. For severely affected houseplants that can tolerate outdoor temperatures, move them outside and ideally place them by plants in your yard like calendula, dandelions, milkweed, mint, dill, or marigolds that naturally attract aphid predators like ladybugs. This ensures that when you introduce the predators, they stick around to finish the job. 

Pro-tip: If you want to introduce predators, don’t use insecticides or soaps as these may kill off your predators as well as their prey. 

Aphids are part of most outdoor and garden ecosystems, so don’t panic if you see a couple. Indoors and when an infestation starts is when you need to begin treatment as you don’t want them to spread. Using the above techniques should help you keep your population of Aphids under control and at natural levels.