Most of us have a love-hate relationship with insects. We love them when they’re far away, and we hate them when they’re around us. While there’s no doubt that every creature has its place in this world and serves an essential purpose, it’s hard to remember it sometimes. I can’t speak for everyone, but my memories of my amateur gardening days are still tainted by the horror of finding what seemed like millions of tiny green bugs lounging on the surface of my plants.
The worst part of garden pests like aphids visiting us in our gardens? They never come alone, and they never plan on leaving. Younger me did the only thing one shouldn’t do in that situation: panic. When dealing with an aphid infestation, speed and precision is the name of the game. While it’s all well to will the parasitic insects away, it rarely (read: never) works. However, some things do work. Luckily for you, we’ve figured out what they are. And while you may already know how to get rid of ants, wasps, spider mites or other insects, you should also know about aphids. Keep reading to get the rundown on them and find out the best DIY ways to keep them far, far away from your precious greenery.
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Aphids: What are they, and how to identify them?
Almost everyone knows about, has heard of, or seen aphids at some point in their lives. It’s hard not to, considering there are more than 4000 species of the little critters, around 250 of which are frequent garden guests. Aphids are pests that are destructive for plants and an all-around nuisance for humans. The bugs settle on plants and suck out the sap from their vascular system, depriving the plant of nutrients. However, not all pests are aphids. It is important to identify the insects inhabiting your plants so that you can purge them accordingly.
Aphids are pear-shaped, soft-bodied insects that are no longer than 7 mm when fully grown. They come in various colours, ranging from green to yellow, brown, red, and even black or white. Some aphids may have a distinctive waxy or woolly coating. It’s easy for the human eye to miss them because they’re so small and usually blend into their surroundings. Aphids are not particular about their living arrangements and can be found on most fruit and vegetable crops, flowering plants, and some trees and bushes.
There are different species of aphids, and usually, one type of aphid sticks to one kind of plant. However, some species are not shy of feeding on multiple plant species. So how else can you identify aphids? Simple, they’ll leave behind clues at the scene of the crime. Curled leaves are usually the first symptom displayed by affected plants. That’s not all, though.
When aphids feed on plants, they produce a sugary, sticky substance called “honeydew” as waste. If you spot it on or near your plants, aphids are sure to be close by. Another red flag is the appearance of ant colonies. Ants feed on it as well and tend to be found near aphid collonies. Lastly, black fungal growth called sooty mould, often found on the underside of the leaves, points towards insect infestation. The fungus feeds on honeydew produced by aphids and harms the plant.
Aphid life cycle
Aphids may be small, but they sure pack a punch. These insects aren’t exactly harmless themselves, but their presence can also be an indicator of a more significant underlying problem in your garden. However, you can’t address that problem before dealing with the aphid population unless you want to lose your plants to aphid damage.
These pests are such a menace that they multiply at incredible rates, making them seem virtually impossible to eliminate. Due to the peculiar life cycle and reproduction process of an aphid, most of the time, there is no waiting period for aphid eggs to hatch. The female aphid produces live female nymphs, up to 80 per week, that mature quickly and birth even more aphids. Therefore, by the time you’re done killing one generation of aphids, several more have taken their place.
There’s more! While most aphids don’t have wings, when the population has increased so much that it starts crowding a plant, aphids may develop wings. This will allow them greater mobility, and they can move to and colonise other plants. In the worst-case scenario, this can cause an infestation in most of your garden plants.
Why are aphids dangerous for your plants?
With all this trouble, you must probably be wondering if you can get away with doing nothing. The answer is no, and here is why.
- Aphids feed on the lifeforce of plants. When colonies of aphids start sucking out the sugar-rich plant sap, they’re depriving the plant of vital nutrients it needs to survive. A lack of these nutrients in the plant can lead to leaves yellowing, wilting, and shrivelling up.
- When aphids make homes on flowering plants and feed on them, they may affect flower and fruit production. The growth of flowers and fruit may be stunted, and they may grow up to be deformed and unviable.
- Galls, which are abnormal cell growths found on leaves or roots, are caused by insects like aphids chewing on plant parts. At best, these are unsightly. At worst, they hinder plant growth.
- Sooty mould due to aphids’ honeydew can blacken the surface of the plant leaves and branches. Ultimately, this may hinder photosynthesis, a process by which plants make their food, and cause the plant to suffer from malnutrition.
- Aphids are disease carriers and spreaders. They can spread viruses between plants, causing symptoms like mottled foliage and weak growth. Viral diseases in plants cannot be treated, so you have to dispose of any infested plants.
How to get rid of aphids step-by-step
The first step is to eliminate all the large aphid clusters by wiping or rubbing them off with a cloth or squishing them with your hands. This is especially effective when dealing with an infestation on smaller plants. Be sure to look under the leaves for aphids, as that’s often a hotspot.
Then, move towards pruning infected branches and leaves that cannot be salvaged. If a plant has become overrun with aphids, cutting back heavily infected areas can streamline efforts.
Next step, water. Using a garden hose to douse the plant with a strong stream of water should dislodge aphids. Once run off with the water, they shouldn’t make their way back to the plant. This process must be repeated several times (no more twice per day) until the population lessens. Allow the leaves to dry between sprays to reduce the risk of blight.
Sometimes, you have to fight fire with fire and insects with insects. Beneficials are those that are the natural predators of aphids. Their presence regulates aphid populations. The natural enemies of aphids include ladybugs, parasitic wasps, lacewings, and hoverflies. Aphids are the food of choice for ladybug larvae, so introducing a population of ladybugs should help you get rid of aphids on outdoor plants. Spraying some water on the plants and releasing the insects in the evening will ensure that they hang around and remove most of the aphids.
People are often wary, and rightly so, of using chemical ones as they can harm the plant or beneficial insects. Making your own insecticide using liquid soap reduces this risk and gets the job done too. Take around 1 litre of water in a spray bottle and add a few teaspoons of dish soap. To increase potency, you can also add a pinch of cayenne pepper to this mixture. Spray this concoction on the plant to kill aphids, but use a directed approach to only spray it on affected areas and preferably later on in the day. Reapply as needed. Another good idea is to dust the plants with flour to constipate the aphids and get rid of them.
Insecticidal soap for houseplants
Insecticidal soap is the insecticide of choice, especially when dealing with indoor plants. You most likely can’t drench your houseplant with a stream of water or bring insects (even though they are beneficial) inside your home, so this is the next best thing. Surfactant or fatty acid-based pesticides are less harmful than chemical pesticides and should be preferably used. Be sure not to use any broad-spectrum pesticides as these might kill good bugs as well. As before, use a directed approach and do not cover the entire plant with insecticidal soap as that will do more harm than good.
Experts and amateurs alike swear by this natural repellent to deal with aphids. This non-toxic, plant-based oil works like a charm to kill aphids, as well as other pests like mealybugs and beetles. It is incredibly potent and readily available. You can easily buy neem oil in its pure form, dilute it with water to form a 2% solution in a sprayer, and then spray it precisely on the aphids to smother and kill them. Once again, be careful to keep neem oil solution away from your beneficial friends to keep them safe.
Smart tips to control aphids and prevent an aphid infestation
Fertiliser and water
Remember how I said that aphids could be indicative of an underlying problem? Well, that problem can be an inappropriate amount of water or fertiliser. Aphids are attracted to lush, new growth, and too much fertiliser and overwatering are the top reasons for excessive new growth. The trick is to find the golden mean of fertiliser (preferably organic and slow-release) and water to ensure you don’t go above or below it.
If you keep an eye on your plants and perform regular soil checks, you should be able to catch an aphid problem before it becomes a full-out infestation. More importantly, plant checkups will allow you to determine if plants are under stress (such as during drought) and carry out pest control.
Plants under stress are more vulnerable to aphid attacks. Using the example of drought, underwatered plants have more concentrated sugar and nitrogen, which is all the more attractive for aphids. Therefore, due diligence in plant care is necessary to prevent aphids.
Diatomaceous earth (DE/diatomite) is a substance that acts as a repellant to aphids since its surface slices up soft-bodied insects. It is, however, completely safe for humans and animals. Sprinkling food-grade diatomaceous earth on plants will create a barrier that aphids cannot cross, thereby protecting plants from these pests. However, moisture washes off DE, so it needs to be reapplied after rain, irrigation, and high humidity.
Kill ants to control aphids
Ants and aphids have a symbiotic relationship through which both benefit. Ants attack the natural predators of the aphids to protect them, and the aphids, in turn, provide the ants with their favourite honeydew. As long as ants are present, the beneficial insects won’t be able to kill the aphids. Therefore, you should moderate the presence of ant colonies to make space for beneficial ones that will prey on aphids.
Companion planting is arguably the best prevention technique and is practically foolproof. Companion plants encourage aphids to inhabit the companion plant rather than other plants or discourage aphids from inhabiting plants altogether. Plants such as nasturtiums, nettles, and calendula are examples of the former. They lure aphids to themselves like moths to a flame. If these plants are planted next to valuable plants, aphids will go over there and leave the other plants alone. Companion plants such as marigolds and catnips are examples of the former. These plants, along with other strong-smelling plants like oregano, chives, sage and fennel, repel aphids away from plants.
I hope now that you’ve gone through this guide, you understand that while aphids are a big problem, they are not indestructible. In fact, if you’re quick to take action and use a proactive approach to kill aphids, you’ll be able to get rid of them quite easily and protect your plants from any damage. As always, it is best to remain vigilant and prevent an infestation in the first place using the tips outlined above. However, if the prevention fails, you don’t have to worry as you now know the cure too. Good luck!