Aphids must be one of the most malicious garden pests and their occasional infestation of house plants is our own fault as we can bring some infected flowers home from the "wild". The danger of these plant lovers is that, unlike all other insects, they have powerful defenders, i.e. ants. Aphids form a symbiosis with ants, so you will have to eliminate the latter as well. In this guide you will learn many ways of getting rid of aphids: natural and powerful ones. In our list of top-7 Best Aphid Killers, we have collected the widest possible range of treatments for plants’ leaves and root system: Insect killing soap, spray, granules, sticky traps and powerful insecticides.
How to Tell Aphids Apart from Other Pests?
Aphids prefer plants with sweet juices. And by sweet, we don’t mean the common idea of sweetness. In the wild, nature sweet plants are dandelion and spurge, among vegetable crops these are tomatoes, and among domestic plants it is hibiscus. How do you know your plants have been infected? Infected plants are dry, withered and die slowly for no apparent reason. Once deprived of juices sucked out by pests, they will inevitably turn into mummies. But keep in mind that other insects, such as fungus gnats, can also drink houseplants’ juices. In this case, you will notice larvae swarming in the soil and adult flying gnats around the flowers.
If you notice disease signs on your trees, flowers, bushes or garden plantings, arm yourself with a magnifying glass to make sure it is aphids that are the pests to blame. As the University of California experts comment, aphids have soft pear-shaped bodies with long legs and antennae and may be green, yellow, brown, red, or black depending on the species and the plants they feed on. Most species have a pair of tube-like structures called cornicles projecting backward out of the hind end of their body. The presence of cornicles distinguishes aphids from all other insects. Although they may be found individually, aphids often feed in dense groups on leaves or stems. Unlike leafhoppers, plant bugs, and certain other insects that might be confused with them, most aphids don't move rapidly when disturbed.
An aphids’ life cycle is terrifying from the point of view of a farmer: in a warm climate, they breed year-round, and each individual can lay up to 12 eggs a day without mating. A young nymph changes skin four times before becoming an adult, but it happens very quickly, within a week. And if ants come onto the scene, be sure to expect trouble!
Aphids and Ants Symbiosis
Although ants are useful industrious insects, they stimulate aphid reproduction to a great extent. The matter is that tiny aphids have a special proboscis for piercing a young plant’s tender surface and sucking its juice to obtain the proteins necessary for life. Aphids emit these juices in the form of waste sugar-sweet droplets, called honeydew. Ants have found this delicious. Not only do they taste aphids, they managed to domesticate these walking confectionery factories. They began to take care of the aphids, protect them, and even transfer them to new plants, where the leaves are more gentle and juicy by gently squeezing aphids with their mandibles. They behave just like shepherds leading herds of cows, goats and sheep to grassy meadows. In winter, ants carried to underground caves part of the warded insects for wintering, according to the myrmecologists.
All in all, no matter how much you pity these tiny workers, you will have to resort to complex insecticides to get rid of ants shepherding aphids in your garden. Or at least start with organic methods.
How to Get Rid of Aphids Naturally
Diatomaceous earth is the most popular means of treating hundreds of insect species. Diatomaceous earth is a natural sedimentary rock. It contains silica, alumina and iron oxide.
Diatomaceous Earth. I have personally used it as a pesticide to treat my mom’s lot from various insects, including aphids and ants. Its action is based on destroying the protective layer on the insect’s exoskeleton leading to dehydration. We’ve poured this powder directly on pests attacking flowers and tomatoes. The ants disappeared immediately, the sprinkled aphids died the next day and in general, their population has reduced sharply. Nevertheless, most of the plants had already been badly damaged by that time. Before applying diatomaceous earth, there is no need to water the plants and soil too much as the insecticide’s performance will worsen in highly humid conditions. Safer Brand 51703 Diatomaceous Earth for ~$9.47 has worked well against pests. Check the current price
Soap solution and clay. Try treating infected plants with a soap solution. Overcast weather is preferred for this activity so that the soap drops forming non-evaporable lenses on the leaves don’t cause sunburn on plants. Soap dries the aphids but its effect may not be sufficient. You can smear tree trunks with clay, put plastic or foil skirts on them, but this method is only possible if you have large plants.
Garlic. Mix two cups of water (500 ml) with four tablespoons (20 ml) of garlic powder in a sprayer. Spray plants’ leaves, window sills and other places frequented by ward ants with this solution. Pests will be deterred by the aggressive garlic smell and will stay away from it. This treatment only repels the insects without killing them. You can also grind a few garlic cloves and arrange them around the places of aphid breeding. These insects also detest the smell of mint or catnip. Like garlic, they do not kill, but only repel insects.
Natural enemies. UC IPM scientists claim: “Natural enemies can be very important for controlling aphids. Among the most important natural enemies are various species of parasitic wasps that lay their eggs inside aphids. Many predators also feed on aphids. The most well known are lady beetle adults and larvae, lacewing larvae, soldier beetles, and syrphid fly larvae."
They are available on the market. 1 500 live ladybugs cost only from ~$10.74 and they are a best-seller in Beneficial Pest Control Insects category on Amazon.com. Lady beetles eliminate not only aphids, but also other garden pests, especially ones that move slowly: mites, scales, thrips, leaf hoppers, mealybugs, chinch bugs, asparagus beetle larvae, whitefly and others. Quick shipping guarantees that you receive live ladybugs. Price: from ~$10.74 Check the current price
Silver-colored reflective mulches. Silver-colored reflective mulches are yet another option. Its use is not as simple as it seems: if the soil is too moist, fungi will multiply and some insects (in our case those were mole crickets, which are even a bigger problem than aphids) will also be attracted. Still, give it a shot as perhaps it will prove effective in your particular case. Silver-colored reflective mulches’ prices start at ~$22.94.
If all of these methods were in vain, opt for insecticides.
Aphid Killers Comparative Chart
|Type||Active ingredients||Action||Best Use|
|Diatomaceous Earth||Organic insect killer||Contact action: the particles cut the insects' exoskeleton and cause dehydration.||Pour on dry plants and soil, don't water plants before application.|
|Live Ladybugs||Biological killer||Consume aphids.||Set the ladybugs directly on the contaminated plants.|
|Sticky traps||Glue surface||Catch flying aphids.||Supplementary outdoor control.|
|Natural Insect Killing Soap And Sprays||Neem oil, potassium salts of fatty acids and pyrethrins||Kills pest insects on contact.||Dissolve in water and spray plants every 7-10 days. Use both indoors and outdoors.|
|Killing Granules, Spikes And Liquid Concentrated Insecticides||Imidacloprid||Penetrates the roots and poisons pests feeding on plant juices.||Stick the stakes into the soil, use granules in greenhouses. This is a concentrate, profitable for use on large lots.|
There are three types of killers, distinguished by their action: repellents (as a rule, consist of natural ingredients), damaging (diatomaceous earth, fungi, parasites, systematical products) and complex ones which eliminate not only aphids, but also other pests including aphid wards, i.e. ants.
We have prepared a review of products covering the widest range of possibilities for controlling aphids.
- The first and most popular ones are organic products, based on neem oil or pyrethrins (botanical insecticide from the chrysanthemum flower).
- Insect killing soap made of potassium salts of fatty acids is also organic and can be used until harvest.
- Sticky traps are helpful for catching adult flyers at home and in the garden.
- Granules and spikes are stuck into the ground to remove insects bred at home on a hibiscus, or other potted flowers. Their active ingredient, imidacloprid, will slowly be absorbed by the plant’s root system during watering and will poison aphids.
- Imidacloprid-based concentrated liquid insecticide is the most powerful and economical control product.
Garden Safe Neem Oil Extract Concentrate
The most popular natural treatment is based on neem oil containing sharply smelling substances. In general, neem is used in India as a panacea for almost all diseases, but aphids cannot stand it. Organically oriented farmers are fond of this product. It is affordable and costs ~$15.31 per 16 oz, and can be used even when harvesting.
It is therefore no wonder that neem oil extract is not only the safest, but also the most popular means of getting rid of garden pests. It serves both as a fungicide and aphid and tick repellent. Its rating of 4.3 stars out of 5 on Amazon.com is an excellent result taking into consideration fierce competition on the market. Read over 600 customer reviews to learn more about its efficiency.
Price: ~$15.31 Check the current price
Trapro 20-Pack Dual-Sided Yellow Sticky Traps for Flying Plant Insect Like Fungus Gnats, Aphids, Whiteflies, Leafminers
Classic bright yellow sticky sheets in a 20-pack set for ~$11.99 attract all flying insects, not only aphids, but also fungus gnats. They are very easy to use, non-toxic, designed for indoor, garden and garden plants pests, and are therefore most often used in greenhouses and at home. Despite the manufacturers’ claims of the traps being ineffective against flies and mosquitoes, buyers share their successful experiences of using sticky sheets for catching mosquitoes.
In general, these sheets are irreplaceable for indoor use. However, sticky traps alone will not be able to deal with an infestation, so combine use with insecticides. Also, replace sheets covered in dead insects in time. The customers’ rating of 4.3 stars out of 5 is quite high.
Price: ~$11.99 (20-pack) Check the current price
Safer Brand 5118 Insect Killing Soap - 16-Ounce Concentrate
This killer soap solution contains potassium salts of fatty acids. The product has already been awarded a rating of 4.2 stars out of 5 and over 500 positive reviews on Amazon.com. It has a number of advantages: first, soap prevents the active ingredient from sliding off and literally wraps around the insects killing them on the spot. Second, 16 ounces for ~$15.94 will be enough for six gallons of water meaning that even the smallest pack of this concentrate will enable you to treat several acres.
Repeat treatment every 7-10 days, even right before harvesting: killer soap indeed contains almost 50% of soap which can be easily rinsed. The only restriction is that it is not recommended for use in temperatures higher than 90ºF so as not to harm the plants. If your garden is quite immense, use a double-sized pack for ~$34.98.
Price: from ~$15.94 Check the current price
Garden Safe 80422 Houseplant and Garden Insect Killer
This ~$12 spray kills pests, including aphids, on contact. Its active ingredients are natural pyrethrins, so it is safe for humans and can be used both indoors and outdoors.
This spray is hardly economical as you need to treat plants in such a manner so that, as Alan Alt, USA put it: “the liquid needs to drip off both sides of the leaf.” The experts recommend topical application on individual plants that are most infected. This spray can exacerbate allergy patients as, judging by the reviews, the fog remains intact for quite awhile after spraying, so don’t forget to ventilate the room after indoor use.
The reviews are contradictory and the product’s rating is only 3.9 stars out of 5. However, it has obvious advantages: many target pests, affordable price and natural ingredients, so give it a try.
Price: ~$12 Check the current price
The following three products are powerful imidacloprid-based insecticides: granules, spikes and a liquid concentrate. Imidacloprid can hardly penetrate fruits and its maximum concentration reaches only leaves and stems. It is also used for getting rid of ants, which makes it perfect for our case as you will kill two birds with one stone and remove all of the pests from your plants.
Bonide Product 951 Systemic House Plant Insect Control, 8 oz
This is systemic insecticidal granules for ~$8.97. Pour them topically around the plants and even dig in the soil a bit. When watered, imidacloprid will be washed off its shell and reach the plants’ root system where it will poison the parasites. It promises long lasting insect control for 8 weeks. This is a great method for getting rid of root aphids, but it is not cost-efficient on large territories. That is why it is typically used indoors on pot plants or, in case of a complex simultaneous infestation of aphids, mealybugs, midges and other insects. Seven out of ten users on Amazon.com gave a high rating to these granules.
Price: ~$8.97 Check the current price
Bayer Advanced 701710 2-in-1 Insect Control Plus Fertilizer Plant Spikes, 10-Spikes
These are popular cut-rate insecticide spikes for indoor and outdoor potted plants for ~$5.98. Their active ingredient is imidacloprid. They also contain mineral fertilizers, such as nitrogen, phosphate, soluble potash, magnesium, molybdenum. Use them just like granules: stick them into the ground near infested plants.
When watered, the combined active ingredients will penetrate the plant’s root system and poison any parasites there. The product can eradicate spider mites, aphids and thrips for up to 8 weeks in a row, acts as a barrier and is harmless. Rubber plant, gerbera, grapes, container bushes and trees are also treated well with it. However, if you own a large lot, opt for something more cost-efficient, such as a concentrated liquid insecticide.
Price: ~$5.98 (10-pack) Check the current price
Bayer Advanced 701615 12 Month Tree and Shrub Protect and Feed Concentrate
The most powerful product reviewed is the imidacloprid-based liquid concentrate for ~$69.97 per gallon. It is successfully used for treating plants, bushes and garden flowers and prevents relapse. The manufacturer promises that a single use will provide a year of protection. This is a both cost-saving and complex approach. If your garden is huge, you won’t find a better treatment for your plants.
Users give this product an unprecedented rating of 4.5 stars out of 5. “This works great to stop/prevent aphids and destructive pests. We had a terrible infestation killing shrubs and plants. I used this product at the end of winter and it protected everything for the entire season. We now use it every February for annual protection.” They claim that this is a great alternative to professional extermination which turns out to be 3-4 times more expensive. Read all reviews on Amazon.com to learn more.
Price: ~$69.97 Check the current price
Aphid Control Products Comparison Chart
Safer Brand Diatomaceous Earth
|Organic killer||Diatomaceous Earth||Don't water soil and plants before use.|
1500 Live Ladybugs
|Biological killer||Ladybugs||An environmentally friendly killing method.|
Silver-colored reflective mulches
|Repellent||–||Don't water soil and plants before use.|
Garden Safe Neem Oil Extract Concentrate
|Natural repellent||Neem oil extract||This repellent and fungicide is the most popular aphid control method.|
Trapro 20-Pack Dual-Sided Yellow Sticky Traps
|Sticky traps||Glue surfaces||Kills flying insects only.|| |
Safer Brand 5118 Insect Killing Soap
|Natural insect killing soap||Potassium salts of fatty acids||It is a cost-saving organic product for treating a large garden. Use every 7-10 days.|
Garden Safe Houseplant and Garden Insect Killer Spray
|Natural killer spray||Pyrethrins||A safe organic spray for a small-scale infestation.|
Bonide Product Systemic House Plant Insect Control
|Killing granules||Imidacloprid||Perfect indoor treatment providing long lasting insect control for 8 weeks.|
Bayer Advanced 2-in-1 Insect Control Plus Fertilizer Plant Spikes
|Killing spikes||Imidacloprid + total nitrogen, phosphate, soluble potash, magnesium, molybdenum||Dual effect of insect control and soil and plant fertilizing. Long lasting insect control for 8 weeks.|| |
Bayer Advanced 12 Month Tree and Shrub Protect and Feed Concentrate
|Killing concentrate||Imidacloprid||The most powerful and economical treatment for a large-scale outdoor infestation.|
When getting rid of aphids, remember to eliminate their protectors, namely ants, as well. You’ll find the most effective treatment methods and products in our review of 20 best ant killers.