One of the most notorious plant pests in the insect world, aphids can quickly destroy an entire crop. But what are these aphids, and where do they come from? This article will be your guide to all things aphid.
Though only 1/16 to 1/8 inch long, aphids are a common garden pest found worldwide, with most of the population centered around temperate regions.
Aphids are called many names across the world. They can be the greenfly or the blackfly, depending on their color.
And sometimes, you might even see them hanging out with ants.
Let’s learn more about these very small but highly destructive crop pests.
What Are Aphids?
The term aphids refer to all the insects that fall under the subfamily of Aphidoidea. Aphidoidea contains over 4,000 species of aphids – all of which feast on plant sap.
Aphids use their piercing mouth parts to suck out the sap of a plant, which can be very harmful to younger, tender plants.
Even larger crops may fall to an aphid infestation – even if the insects are only a few in number. Infected crops have distorted leaves and might contain plant viruses and parasitic wasps.
They have very fast life cycles, requiring only ten days at the most to reach maturity. Females also egg in large numbers. The control of aphids is necessary for any healthy garden.
What Do Aphids Look Like?
Aphids have pear-shaped, soft bodies which can be either green, red, brown, pink, yellow, black, or even colorless.
The color usually signifies the type of plants they feed on. Some aphids can have waxy or woolly exteriors (such as the Woolly apple aphid).
They have two antennae upfront, compound eyes with three lenses, and a tail-like structure at the back.
Most aphids will also have two cornicles at the back, which is a tube-like protrusion from either end of their abdomen.
These tubes can spray cornicle wax, which is a quick-hardening liquid used for defense.
This is one of the distinguishing features that help identify aphids.
They can be both – non-winged and winged forms.
Types of Aphids?
There are over 4,000 species of aphids, but here are some of the more common ones:
- The rosy apple aphid, which lives on rose flowers
- The woolly apple aphid which thrives on the roots of apple trees
- The potato aphid is born on rose plants and then migrates onto potato and tomato plants
- The pea aphid is born on alfalfa or clover and finally attacks pea plants
- The green bug attacks wheat, oats, and other grains
- The corn root aphid, which feeds on corn roots
- The cabbage aphid that thrives on cauliflowers, brussels sprouts, and cabbages
- The melon aphids which attack melons
- The green peach aphid eats over 40 different plants
Do Aphids Jump?
Aphids cannot jump or hop. Their main mode of transport is crawling, walking, or hitching rides.
For example, ants will sometimes guard aphids to get access to honeydew (an excretory product that is sweet and encourages fungal growth) and, in return, transport aphid eggs.
Most aphids are wingless (including all females).
However, some aphids do have wings that help them leave one plant and go to another when the colony size gets too large.
Hence, they can fly short distances.
What Do Aphids Eat?
All aphids feed on plant sap; however, what plant they feed on will vary from species to species.
Among the thousands of species, they pretty much cover every tender plant you can think of.
Different species feed on apples, peas, cabbages, rosebuds, ornamental plants, woody plants, corn, melons, and more.
Root aphids specifically feed on the roots, whereas others may attack the leaves and stem region.
Very few aphids (only 10%) are actually monophagous – which means they only eat a few specific plants type.
Most are okay with all varieties of sap. Some, such as the Myzus persicae, feed across hundreds of plant species!
After finding a suitable host plant, aphids use their piercing mouth part (called a stylet) to create a puncture in the xylem of the plant in which the sap flows.
As the pressure is now disturbed, the sap flows into the aphid’s mouthparts, and the plant leaf or stem starts withering due to lack of it.
Do Aphids Eat Monarch Eggs?
Aphids are huge pests for oleander and milkweed plants, which typically attract monarch butterflies.
Attracting monarch butterflies is a great way to encourage pollination in your garden.
While aphids don’t feed on monarch eggs, they can still harm the butterfly population in two ways:
- They attract predators such as ladybugs and lacewings, which do consume monarch butterfly eggs.
- They completely defoliate the plant, leaving it bare of essential nutrients. Hence after the butterfly lays eggs, the caterpillars will have nothing to feed on.
Where Do Aphids Live?
Aphids can live either in the soil or on the underside of leaves and on tender stems of plants.
Soil aphids are generally root aphids and only eat sap from plant roots.
They are whitish or yellowish in color and will leave a whitish-waxy covering or residue near the base of the plant.
This can be a great way to identify if your plant is infested or not.
Root aphids typically attack the roots of apple trees, auricula primulas, grapes, and lettuce.
Aphids that feed on the stem and leaves are usually found on the underside of leaves and large vegetables such as cabbages.
Often, adult females will lay eggs in one location, and the nymphs will migrate onto the host plant later.
For example, potato aphid hatches from eggs laid on rose plants. Initially, the larvae feed on the rose plant.
However, in early spring, they migrate onto potatoes for the summer.
Similarly, the pea aphid starts its life cycle on alfalfa. But will eventually end up attacking pea plants.
Do Aphids Make Webs?
Aphids cannot weave webs akin to spiders. However, they produce honeydew as a byproduct.
Honeydew is sweet and sticky and can often form thin lines across plant stems, giving the appearance of a spider web.
Sometimes, aphids and ants will live in symbiotic colonies, where ants protect the aphid host plant and, in return, harvest the honeydew that the aphid produces.
Honeydew consists of half-digested sweet sap, which is a good source of carbohydrates for ants.
How Do Aphids Come Indoors?
Aphids can move in three ways: they can walk and crawl, hitch a ride on some other insect, and fly (limited to a few).
If you find an aphid infestation indoors, then they probably came in through some crack in the door or window – or perhaps even hitched a ride on you or your pet!
Root aphids live in the soil, and if you have repotted an indoor plant using your garden soil, they could have come along with it.
Life Cycle of A Aphids
Aphids are fast-reproducing insects, and they do so asexually (though sexual reproduction is also documented in some species).
Aphid eggs hatch in spring – usually, each female produces between 40 to 60 eggs.
The young nymphs are all exclusively female and wingless. The nymphs molt four times before finally becoming sexually mature adults.
These aphids (stem mothers) keep producing more female aphids through asexual reproduction (but they cannot produce eggs).
This process is called parthenogenesis and is essentially a type of cloning that is much faster than egg-laying. It is also why aphid infestation happens so quickly.
The wingless female aphids mostly reproduce asexually throughout the year. As winter nears, they cannot survive in the cold. But their egg stage can!
Hence, the last batch is usually male, winged aphids. After fertilization in sexual form with the male, the stem mothers produce eggs that hatch in the coming spring.
Sometimes, if the food source in a place is depleting, the stem mothers can give birth to winged females who can find other host plants.
Do Ants Farm Aphids?
Some ant species do farm aphids!
This is a common relationship seen among many insects and animals in the world.
Ants will sometimes transport aphid eggs onto favorable host plants and then protect the aphid from predators such as lacewings.
In return, the ants will “milk” the aphids to receive honeydew in return.
However, if an aphid does not produce enough honeydew (such as when sick or old), ants in the colony are known to attack and kill the disabled insect.
How Long Do Aphids Live?
A single aphid will usually have a lifespan averaging around a month.
In this, the insect will become sexually mature after anywhere between 4 to 10 days.
Each aphid goes through at least 3 or 4 generations before passing away.
Hence even a few dozen aphids can create large aphid colonies within weeks.
Do Aphids Bite?
Aphids do not have biting or chewing mouthparts. Hence they cannot bite humans or animals.
Moreover, they are herbivores that solely survive on plant sap.
However, they do have piercing mouthparts that they can use to pierce one’s skin.
This is rare, and if it does happen, the poor insect probably thought you were a plant.
Are They Poisonous/Venomous?
Aphids are not poisonous or venomous.
If you happen to get pricked by an aphid, the maximum reaction would be a local swelling, similar to a mosquito bite.
If threatened, they can sprew out conical wax from their cornicles, which quickly hardens and traps the predator. However, it is not poisonous.
What Are Aphids Attracted To?
Aphids, like some other common plant pests like scale and whiteflies, are attracted to light or objects that reflect light that falls within a range of 500-600 nm.
Apart from this, each species will be most attracted to its host plant, which it identifies through touch and smell.
What Eats Aphids?
There are many insects that eat aphids.
Some common aphid predators are ladybugs, lacewings, ladybeetles, damsel bugs, and more.
Ladybugs and their larvae are often touted as a good alternative to insecticidal soap for getting rid of aphids.
A single larva can eat more than 100 aphids in a single day.
There are also some other insects, such as praying mantes, that eat many insects, including aphids.
Can You Eat Aphids?
If it is by choice, I will encourage you to not eat aphids.
They’re too small to be of any nutritional benefit. And while they are not poisonous, they can carry various viruses, which it’s best to steer clear of.
Theoretically, you can eat aphids and remain perfectly healthy.
If you happen to consume one by mistake, as they were on your lettuce or cabbage, it is totally fine (though it might feel icky).
How To Get Rid of Aphids?
There are various ways to remove aphids, both natural and using chemicals. We cover all of it in the sections below.
How To Get Rid of Aphids Naturally?
The control of aphids is tough, but you can try getting rid of aphids in a few natural ways, such as:
- Release natural predators or beneficial insects in your garden. Some like lacewing larvae, will consume aphids and other insects while leaving your plants alone (they are carnivorous).
- Adding Diatomaceous Earth near the roots to kill root aphids. Diatomaceous Earth has a high silica content and is found naturally in some water bodies.
- You can use homemade recipes such as neem oil or vinegar spray to repel them. Mix vinegar with small amounts of acetic acid and spray it on your plant stems.
How To Get Rid Of Aphids On Christmas Tree?
It’s best to carefully inspect a christmas tree before buying to bring forth aphids in your home.
Aphid populations can spread swiftly, and they’re hard to get rid of.
However, if you do happen to notice aphids on your tree, use a vacuum to get rid of them. Do not dust the tree or try to crush them.
They can leave stains or move onto other indoor plants.
How To Get Rid Of Aphids On Cannabis?
There are a couple of things you can try to get rid of aphids on cannabis plants:
- If they are only a few, handpick them off.
- If you see larger numbers that keep coming back, use a jet of water on the infested areas in the morning and evening.
- Spray a mix of insecticidal soap onto the underside of the leaves until you see that the aphids are dead and done. This also prevents recurrence.
- Some smells, like that of neem oil and clove oil, are uncomfortable for aphids and can prevent a recurrence.
What Plants Repel Aphids?
You can use some plants as companion plants to get rid of aphids.
Usually, these are plants with a strong smell, such as marigolds and catnip, which these insects cannot stand.
Herbs that have a strong smell, such as dil, fennel, and peppermint, can also be used.
Onions, garlic, and hot pepper are some other options.
These work similarly to essential oils such as neem.
However, if you have an existing infestation, you might first need to use insecticidal soap to kill them and their strong-smelling plants to prevent a recurrence.
What Temperature Kills Aphids?
Aphids are more sensitive to cold than they are to heat. Low temperatures of around 23 to 5 F is enough to kill them.
On the other end of the spectrum, you will need a temperature of more than 90 F to kill them with heat.
Some aphids are more susceptible to heat than others. At high temperatures, they become inactive and eventually die.
However, aphid eggs can survive much colder temperatures, so you should be careful to weed out those too.
How To Get Rid of Aphids Using Sprays?
The best way to get rid of aphids is to use an insecticide that is effective for them.
With other solutions, there is always a risk of recurrence.
Some insecticide applications that can get rid of aphids are:
- The Sevin Insect Killer, which can be sprayed onto plant stems
- The Spinosad spray. However, it takes some time to work and mainly affects the larvae
- Avid insecticide spray is great for aphids and mites
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Interesting Facts About Aphids
- When in trouble, aphids release pheromones to alert the colony. This pheromone usually sends the colony scurrying for cover.
- Unfortunately for them, some beetles can also follow the pheromone to the aphid’s hiding location.
- Almost every plant in the world is a potential host for some aphid species or another.
- When a female aphid is born, she is already carrying all the embryos that will eventually produce clones or offspring through asexual reproduction!
Frequently Asked Questions
What causes aphids to appear?
Aphids are small sap-sucking insects that can appear on plants and can cause damage to leaves, flowers, and stems.
There are several factors that can lead to the appearance of aphids, including weather conditions, plant stress, and a lack of natural predators.
Warm and dry weather conditions can provide optimal conditions for aphid reproduction.
Plant stress caused by drought or other environmental factors weakens the plant’s defenses against pests.
Additionally, a lack of natural predators, such as ladybugs or lacewings, can allow aphid populations to grow unchecked.
Once they appear, it is important to take prompt action to control the infestation before it causes significant damage to your plants.
What kills aphids instantly?
Aphids can be killed instantly by using natural remedies, such as insecticidal soap or neem oil.
These products will suffocate and dehydrate the aphids, ultimately resulting in their death.
Another effective method is to use a strong jet of water to knock the aphids off the plants, which will also kill them instantly.
It is important to remove any infected leaves or plants and keep your garden clean to prevent further infestations.
Avoid using chemical pesticides, as they can harm beneficial insects and pollinators present in your garden.
What problems can aphids cause?
Aphids can cause several problems for plants and crops, including stunting growth, transmitting plant viruses, reducing crop yields, and even killing plants if populations are high enough.
These insect pests feed by piercing the leaves and stems of plants to withdraw essential fluids, which weakens the plant and makes it more susceptible to disease.
In addition, aphid infestations can attract ants that feed on honeydew secreted by the aphids, further exacerbating the problem.
Sustainable control measures such as introducing natural predators or implementing integrated pest management strategies are often necessary to manage aphid populations effectively.
What kills aphids on plants?
There are several methods for controlling aphids on plants, including natural and chemical options.
Ladybugs, lacewings, and other beneficial insects can be introduced into the garden to help control aphid populations.
Neem oil is a natural insecticide that is effective against aphids when sprayed directly on the plant.
Soap-based insecticides can also be effective in controlling aphids without causing harm to beneficial insects or the environment.
How to prevent aphids?
Preventing aphids, a common garden pest involves several tactics.
One method is to use companion planting techniques where you plant certain plants near each other, such as basil next to tomatoes, to discourage aphids from infesting your crops.
Regularly inspecting your plants and removing any aphids you find can also help prevent them from spreading.
Another option is to use natural predators such as ladybugs or lacewings that feed on aphids to keep their populations under control.
Finally, some organic pesticides can be used as a last resort if necessary, but caution should be taken when using these products as they may also harm beneficial insects.
What is a natural spray for aphids?
A natural spray for aphids is a mixture of equal parts water and dish soap.
Simply mix the two together in a spray bottle and apply it to the affected plants.
The soap will suffocate and kill the aphids without harming your plants.
Another option is to use neem oil, which is a natural insecticide derived from an Indian plant.
Mix 1-2 tablespoons of neem oil with a gallon of water and spray on your plants to repel or kill aphids.
Garlic spray is also effective at repelling aphids, as they dislike the smell of garlic.
To make garlic spray, puree a few garlic cloves with water in a blender, strain out any solids, and mix with equal parts water before spraying onto your plants.
Wrap Up
Aphids can be tiring pests to deal with and are natural enemies of every farmer.
They are especially harmful to crops during the early days as they mostly cannot survive an infestation.
If you see your plant wilt and develop curled leaves, it’s best to check for aphids under and within the leaves.
Some aphids will cause the leaves to curl around them, protecting them from predators and insecticides.
Thank you for reading!
28 Comments. Leave new
I have MANY large oleanders on my property, that we have just noticed are COVERED with aphids. I would definitely say it is a severe infestation. Don’t think dish soap will cut it. We are in the High Desert of Cali. It is late spring, will buying lady beetles do the job or must we attempt to prune less than a third of the foliage? Please help! They are to beautiful to lose.
We do not provide extermination advice.
We have a lot…. Millions… Of these bugs. It is awful!! They are all over the kids toys, swing set and killing my willow tree. I really need help getting rid of them. I won’t let the kids outside now. I spray them with water and they come back. What should I do???
We do not provide extermination advice.
I am experiencing the same problem. They are covering my tree, and other objexts siting in my yard, like our garbage cans. I am spraying them with a mixture of Dawn dish soap and water. They are still in our tree, but I spray around the house etc and have noticed they have slowed down. After spraying, the bugs are kinda dried out, and don’t leave a purple stain like when you crush them.
In green house i planted willow seedlings from last week i oberving the coleoptra in willow ports. could you suugest me any kind of solution to get rid off from these tiny insects.
Spraying the infested plant with mild, soapy water is a long established method to control Aphid populations.
These have just shown up. We’ve lived here for 30 years with large willows and never have seen them before. Thousands upon thousands. Insecticide kills them on contact but seem to be impervious to the residue of the poison and does not affect them. Can’t spray the tree cuz it’s over 60ft tall.
I have been searching for days and I finally have somewhat of an answer. I am happy that I found this because I have the same issue as stated above and it has really been “bugging” me. Thanks for writing this!
Are Black Willow Aphid harmful to chickens? They are all over the outside of my chicken coop.
We don’t believe they will harm your chickens.
Here in Minnesota we had these insects ALL over our backyard. I’ve never seen them before until this year. I did as much research online as I could and came up with nothing till this post. I will say that we did spray with an insecticide. However we ended up spraying the hanging branches of the neighbors weeping willow tree. That worked like a charm and they haven’t come back.
Aphids are dormant from the most part well never. When dealing with these pesky creatures I suggest you hire professional help immediaty. Termnix is a good place to get services. For starter anyhing can be infested with these bugs. Take no chances if you think that than your trusing instincts.
Same here! Our Southeast Michigan yard is infested with millions of these, identical to these. They just appeared—first time in 25 years, and there is a huge willow in our backyard, being taken down as we speak. Hoping for a solution, as this is tge stuff of my nightmares!
Since you removed the tree did the aphids go away? I’m considering getting mine taken down as well but only if it will for sure solve the problem. Thanks!
It seems that this is what we’re being plagued by, here, too, in northeastern New Mexico, in 100 year old Black Willows, Salix Nigra, imported historically from somewhere “back east”. I appreciate reading these accounts so much, thank you everyone, it really helps to finally know something. Our trees are huge, so, don’t know how we’ll deal with them, and are praying they don’t come next year. These same trees had a few of the same black aphids, one year in the 1980s, and none again until this summer. This year is a far more serious infestation, and the trees are looking quite stressed, but it’s also nearing fall. Yes, the stuff of nightmares, I agree!!
Are you talking about the name of the tree or the insect?
first time in 30 years to ever see these little bugs. a pain in the azz. I have been spraying the side of the house and other objects in the yard. hoping a first freeze will eliminate them. weeping willow is over 30 years old and we never had an issue till this year. a purple/grape goo if smashed.
I’m hoping the first freeze will kill the aphids. I was told by a tree pro that the best war to kill these aphids is by using a systemic with imidacloprid around the base of the trees. This insecticide is a neurotoxin known to kill honeybees. He said it would take 5-6 weeks for it to be fully transported into the leaves and become effective. Not wanting to add to the die off of honeybees, I’m wondering about applying next season after trees flower, hoping to miss doing harm to bees. Perhaps by then, I might know if we have a return of the aphids, not ever wanting to go through another summer like this one, I will try it if nothing else presents itself. I wonder if anyone has any experience with trying this approach. Also, if anyone has a successful idea for cleaning off roofs and stones covered by months of honeydew. Beautiful flag stone paving is blackened, and so far, scrubbing with various house cleaners hasn’t done much good.
Saddened to hear any use of pesticides being discussed- when we already know our bees are dying. I have this same problem on my willow screen, but will instead do anything i can – such as letting the birds and ladybirds help by introducing bird feeders to this area – the birds can’t see the aphids unless they get up close, and ladybirds are there and feeding on them. Also, please note that the bees feed on the sticky honeydew the aphids produce so don’t use presticides please.
Dear Debbie,
We agree with you, and we were puzzled by your comment since What’s That Bug? does not provide extermination advice, nor do we promote pesticides. Upon rereading our posting, we realized one of our quotes included a comment about insecticidal soap, so we removed that sentence from the quote, replacing it with an ellipsis. Thanks for bringing this to our attention. Comments from our readers do often include extermination advice.
Have circles of peeled bark around the lower base branch (up to 4′ or so) on some of the black willows around a stream. Sometimes just one horizontal circle of peeled bark, and sometimes several of the perfectly horizontal peeled circles close together on the bark from ground up to about 4′. What is it? How can I kill it. Live in central Colorado.
We have a corkscrew willow which we believe to be hosting these aphids. They are very few that we can see on the willow itself, but they are all over our wooden deck and metal furniture. We can’t use our deck now!
First time this problem and the tree is around 15 to 20 years old, maybe more and over 40 feet tall we guess.
Very discouraging. It we hope the cold coming might slow them down and we will use dormant oil spray in the 2020 spring.
We have a corkscrew willow which we believe to be hosting these aphids. They are very few that we can see on the willow itself, but they are all over our wooden deck and metal furniture. We can’t use our deck now!
First time this problem and the tree is around 15 to 20 years old, maybe more and over 40 feet tall we guess.
Very discouraging. It we hope the cold coming might slow them down and we will use dormant oil spray in the 2020 spring.
The good news is that one year is unlike another. After the summer of 2018 when our black willows were plagued by aphids, they didn’t reappear in 2019, and the trees recovered beautifully. This year has been much rainier than last year, so, I think that had something to do with the invasion we had. I apologise for mentioning an insecticide, I hoped something knew about how to use it skillfully. With such huge trees, I couldn’t imagine ladybugs making a difference before flying away, I really appreciate knowing they amy have worked for someone else.My actual worst nightmare would be to lose my trees, and I’m so glad they’ve survived and done well again.My sympathy goes out to those who felt they had to take down these gorgeous trees.
I am an engineer at Tiny Town, Colorado. At the park we have 7 Willow trees over 60 feet tall. We have a whole bunch of sapling willows along our creek bed. We have had a commercial spray company spray the large willow near the playground, with good results. They stated that they could not spray near the creek bed. That leaves the remaining willows still infected. My question is will these Willow Aphids winter over here in Colorado? This is the first time we have been infected in the last 16 years.
I’m in Deer Creek Canyon, CO, and seeing the same on my huge willow. First time in 25 years up here. I’m hoping they die over winter. Friend at UW said to dust with flour, which constipates them. Alternative is Neem or horticultural oil. Haven’t heard of using flour before, but if it annoys the bicyclists as a side-bonus, it’s worth a try. Would need to engineer a dusting method for a tree this tall… Suggestions?
Can these black willow aphids harm your pets?