They are crawling insects that feed on the sap of indoor and outdoor plants. They are found under leaves, sometimes developing wings, thus giving them the names greenflies or blackflies. If you notice aphids on your plants, getting rid of them quickly is a top priority.
Aphids harm plants by stunting growth, causing wilted foliage and leaf drop. If aphid infestations become very large, one species may end up killing the plant itself. They also produce a toxic substance called honeydew.
They are part of the superfamily Aphiodiodea, the world’s largest group of insects. Over 5,000 species of aphids are known to attack crops, outdoor garden plants, and houseplants. They can measure between 2 and 3 mm long.
This article is a comprehensive guide to controlling aphid infestations on plants. You’ll learn how to control aphids on indoor plants and outside in your garden. You’ll also learn how to prevent infestations by understanding the life cycle of aphids.
What do Aphids Look Like?
The specimens of these tiny insects crawl across plant stems and leaves. They can range in color from green to black to brown, white to pink and gray. When you examine closely, you’ll find they have long legs, antennae, and protruding cornicles.
Aphids that have a waxy or woolly appearance (like woolly aphids) give the plant a fuzzy, shiny appearance.
Aphids on their own are difficult to notice. Their pear-shaped bodies are less than 1/4 inch long (6 mm), but most species are much smaller at around 2-3 mm. They can grow as small as 1 mm long. Since aphids usually feed in clusters, finding a large infestation is easy.
Aphid nymphs look like smaller versions of the adults. Infested plants often have baby aphids appearing alongside mature aphids. However, if you look closely, you will notice their almost translucent bodies along with the mature aphids.
Some species of aphids grow wings. The winged insects are sometimes called greenflies or blackflies. White flying aphids are also sometimes called whiteflies-but they are not true whiteflies. Since they are similar to lice, they are also called plant lice.
Aphids Life Cycle
It consists of three stages, an egg, the nymphal stage and the adult stage, with one of the females producing up to 80 aphids in a week. These pests can infest a whole plant rather quickly.
An aphid’s eggs remain attached to the underside of leaves during the winter and hatch in spring. Nymphs hatch quickly and reproduce prolifically. Female aphids can produce eggs asexually, so they don’t require a mate.
In the spring and summer, aphids lay eggs on the underside of leaves. In the fall, the males mate with the females, laying eggs inside them. Consequently, new generations of aphids lie in wait to attack plants the following spring.
When aphids flourish during active seasons, pest control methods are vital to preventing females from breeding. During the winter dormant season, applying horticultural oils can help prevent aphid eggs from hatching.
Where do Aphids Come From?
The aphids descend on your home from the underside of leaves or crevices in plant stems where they’ve been overwintering. They can also enter through open windows or contaminated soil, or they can fly in through newly-purchased houseplants.
The small size of aphids allows them to hitch a ride into your house on new plants. Therefore, always inspect new houseplants. Look carefully for eggs on the leaves and look closely at all parts of the plants for crawling aphids.
Aphids lay their eggs in soil, from where they emerge in the spring. So you have to repot your houseplants, disposing of the old soil in case there were eggs. Replacing the potting mix can help save you from pest problems this way.
How to Identify Aphids
The small insect pests can be identified either by looking for them or by observing plant damage. Phids are small, pear-shaped insects found in small colonies on leaves. You may also notice a honeydew compound on plants or misshapen, curling leaves.
Identifying sap-sucking pests is not difficult if you have a significant infestation. You will see many small insects en masse on plants. However, a magnifying lens is needed to spot specific aphids under leaves.
What to look for when identifying aphids are:
- From the side, these insects resemble miniature grasshoppers with their long legs.
- The hind legs have two protruding tube-like structures.
- Slender insects ranging in color from green to black, pink to white to gray to yellow to brown.
- There are lots of different kinds of aphids, and some of them have wings.
You can also see aphids damage plants by excreting a sticky substance on leaves and stems. If your plants are sticky or have tiny bugs crawling over them, it’s a sign you’ve got aphids.
Besides honeydew and sooty mold, ant activity may also signify an infestation of scale insects or mealybugs. Therefore, it’s important to check for signs of scale insect infestations or mealybug damage as well.
Aphid Damage to Plants
The damage produced by aphids on plants is widespread. The pest causes yellowed leaves, stunted growth, and disheveled appearances. As the aphids feed on the plant’s juices, the plant loses nutrients, eventually leading to death.
An aphid population on a healthy plant rarely causes much damage, however when one population grows it weakens your plant, making it susceptible to several other problems. In addition, aphids quickly move to neighboring plants, causing them damage as well.
Here are signs of plant damage that aphids can cause:
Yellowing leaves. The leaves are usually the first part of the plant to suffer when aphids attack. Aphids starve the leaves, resulting in a loss of color, dryness, and premature dropoff.
Curling leaves. Another problem with some aphids is that they inject toxins into plant tissue. This toxic substance causes the leaves on plants to curl.
Honeydew. Although honeydew itself is not detrimental to plants, it attracts other insects that can cause damage. Bees and ants are attracted to honeydew, which in turn keeps aphids safe from predators such as ladybugs and lacewings.
Black sooty mold. Black mold is a dark-colored fungus that grows on leaves when honeydew is present. It stops photosynthesis from taking place, so plants can’t obtain the nutrients they need to stay healthy.
Gall formations. The galls that some species of aphids cause make plants look unsightly while not harming them. Although harmless to plants, these growths are unsightly.
How to Get Rid of Aphids on Plants
The first step in taking care of aphids on houseplants is to isolate the infested plants. The next step is to eradicate them using natural methods such as keeping the plants clean and spraying them.
When aphids appear, swift action is essential. They reproduce rapidly and can quickly become unmanageable.
To manage aphids, it is best not to use synthetic pesticides. Besides killing beneficial insects, many pesticides are toxic and not safe around humans and pets. In addition, using insecticides on vegetables or fruit trees can pollute the food chain.
Isolate and Prune Plants
The plants should be isolated from other houseplants to prevent further infestation. Once isolated, check the stems and leaves for damage. Prune foliage that is heavily infested and dispose of contaminated parts in the trash. While the plants are isolated, apply natural aphid treatments.
In addition to checking the underside of the leaf, you can also look for signs of activity around the base of the stem. Some aphids are also active in the soil, so you may want to repot the plant with sterile potting mix.
If you want to get rid of most aphids from plants, you can use a strong jet of water in the shower. Keep the plant in the bathroom and spray the foliage with the jet of water to dislodge aphids.
Aphids can be removed from delicate plants by dipping them in clean water.
Aphids are common in outdoor plants. Use strong enough water pressure to remove them from the foliage, while avoiding harming the foliage. Thoroughly douse the plants in water, ensuring that aphids are blown off the underside of leaves.
Adding two teaspoons of neem oil to one teaspoon of Castile soap and 1 quart of lukewarm water to a spray bottle will kill aphids. Spray your plants liberally with the mixture for getting rid of aphids.
The oil disrupts the reproduction process of aphids, which is why neem oil is needed to remove them permanently. Neem oil is necessary to kill most houseplant pests, including aphids. Aphid sprays containing neem oil also have a residual effect, so they will continue to affect aphids after application.
The oil is used by organic gardeners to treat aphids on flowering plants like roses. It can also be used on vegetables like peppers and tomatoes. Neem oil is an organic pesticide which is the best option because it’s safe.
Homemade Soap Spray
1-2 teaspoons of liquid dish soap or Castile soap and 1 quart of lukewarm water are combined in a spray bottle in order to eliminate aphids from the plant permanently. Spray the solution all over the plant to find aphid colonies and target them.
The soapy solution can be applied to the leaves to remove the aphids and any eggs. Dip a sponge into the soapy solution and gently wipe the leaves to remove the eggs and aphids.
After applying the natural bug-killing soap, allow it to dry for up to two hours, then rinse the soap residue off the leaves with clean water to avoid any damage to the leaves.
Liquid dish soap works as an effective aphid control because it suffocates the little critters. The fatty acids in the natural liquid soap break down the insects’ soft bodies, causing them to suffocate and die.
It is extremely effective to kill all types of aphids with 70% rubbing alcohol applied directly to crawling aphids; to eliminate larger infestations, pour some rubbing alcohol on a damp cloth, and wipe down the infested leaves.
For problem pests like aphids, apply a solution of 1 cup of alcohol diluted in a quart of water. Spray liberally on the underside of leaves to get rid of greenfly. Continue spraying until pests have disappeared for good.
A cloth soaked in a diluted alcohol solution can be used to wipe leaves to remove aphid eggs during the dormant stage in winter. Alcohol kills eggs on contact, preventing them from hatching in the spring.
Many household pests, including aphids, can be eradicated with alcohol because it breaks down the insects’ outer layer.
Epsom salt kills aphids without being toxic to plants. Simply mix two tablespoons of Epsom salt with one or two teaspoons of Castile soap in a spray bottle and spray your plants well.
To prevent scorching of leaves on outdoor plants when using Epsom salt aphid treatments, apply the chemicals at night and wipe residue off leaves the next morning. Epsom salt is effective on edible plants such as tomatoes, and ornamental plants such as roses.
Aphids are believed to be killed by Epsom salt pesticide and deterred from coming back by repelling new pests.
If your plants are infested, apply natural aphid treatments on your plants while using sticky traps to control the spread of aphids. Aphids stick to sticky traps and stop causing problems on your plants.
Diatomaceous Earth (DE)
Diatomaceous earth kills aphids by dissolving the softer bodies of the bugs and forcing their dehydration so they will die. Dust plant foliage with diatomaceous earth to get rid of aphids.
Remember that diatomaceous earth can only be used to get rid of aphids from dry foliage.
It’s not harmful to humans, but it is a fine powder, so don’t forget to wear a mask and eye protection when using diatomaceous earth to kill aphids.
How to Prevent Aphids on Plants
If you want to avoid aphid damage on your houseplants or garden plants, the best way is to take proper care of them. Proper watering techniques and the appropriate fertilizer help plants resist pests, including aphids.
You can avoid aphids by taking certain precautions. Here are a few:
Inspect new plants. Check any plant you bring inside for aphids. This includes houseplants that grow outdoors in the summer and plants you buy.
Wipe plant foliage in winter. During the dormant season, wipe plant leaves with a diluted alcohol solution or neem oil to remove aphid eggs from the underside of leaves.
Beneficial insects. Use predatory insects such as ladybugs and lacewings to control aphid populations on outdoor plants. They feed on aphids and help control their population.