11 Scents That Aphids Hate (And How to Use Them)
These pear-shaped insects seem to have zero preference for plants, chowing down on everything from tomato plants to apple trees to rose bushes. With a crazy reproduction rate, it’s hard to imagine being able to control aphids! Luckily, there are certain scents and smells that can be used to repel them from your vulnerable plants.
Aphids use their sense of smell to detect food, identify members of their own species, and detect predators. You can use this to your advantage by using scents like capsaicin, peppermint, thyme, rosemary, neem oil, chives, garlic, petunias, marigolds, and mums to repel aphids from your garden.
When you work hard taking care of your plants and garden, you don’t want it to be ruined by tiny aphids. Read on to find out about all the scents that aphids hate and how to use them!
What Are Aphids And Why Repel Them?
Aphids come in a variety of shapes, sizes, and colors. There are tons of different species, over 4,000 to be exact. But only about 200 of these species are considered pests to crops and gardens.
These insects are small with pear-shaped bodies, long legs, and long antennae. The tough thing about controlling aphids is their insane reproduction rate. Unlike most animals, aphids do not need to use sexual reproduction and can reproduce asexually.
Females can produce as many as 12 live-born aphids a DAY! Woah. That’s over 80 new aphids per week! And that’s just one aphid. Without hurting our brains too much with math, let’s just say aphid populations can explode very quickly.
With that being said, let’s explore some of the damage they can do:
Yellowing leaves and stunted growth: A small population of aphids is not going to wipe out your garden, but a large population can cause leaves to be yellow and will stunt the growth of plants and trees.
Honeydew: Aphids can excrete a sticky substance called honeydew. Oftentimes ants will feed on this, which isn’t the worst thing that could happen. However, sometimes honeydew attracts a sooty mold fungus that will grow on your plant’s leaves, coloring it dark brown to black.
Plant Sickness: Aphids can make plants sick through the transmission of viruses. This is particularly important because you don’t need a large aphid colony for viruses to be transmitted. It only takes a couple of minutes to transmit ailments, but it can take days to weeks for insecticides to work – which is why repelling them with scents and smells is a great preventative measure!
Some aphids attack more than just the leaves: While most aphids eat the leaves of plants, some will attack the roots, eventually killing the plant off.
Which Plants Need Protecting?
Honestly? All of them. As we mentioned before, aphids aren’t very picky about which plants they eat. The University of California has a long list of plants an aphid can affect. These little buggers will even go so far as to eat the leaves of hot pepper plants, which most critters and bugs stay away from.
However, you can usually tell which plants the aphids are favoring by either physically seeing them or by the secretions they leave behind called honeydew.
This honeydew is a breeding ground for a fungus known as sooty mold. This mold is dark in coloration but can be easily washed off with water.
Another tell-tale sign of an aphid invasion is folded-over leaves, which are caused by a toxin aphids inject into the plant. The folded leaves protect the aphids from insecticides and other control measures.
Once you spot this, you can zero in on where the aphids are proliferating from. Concentrate on the perimeter of these areas so that you can contain the aphid population. Natural predators like lady beetles and lacewing flies will help do the rest!
11 Scents That Repel Aphids
Now to the good part!
Here we’ll list 11 scents that aphids can’t stand and how you can use them to protect your garden. After all, that’s just about the only area you need to protect from aphids as they will not enter your home unless by accident on a plant being brought inside.
Use Capsaicin To Repel Aphids
Remember how we said earlier that aphids are brave enough to invade hot pepper plants? Well, the thing about it is they will only eat the leaves. They do not want anything to do with the actual pepper.
Aphids are repelled by hot pepper, which contains a chemical called capsaicin. This is what gives peppers heat and gives us the burning sensation in our mouths. The capsaicin in hot peppers irritates aphids, as they will stay away from plants as a result.
Companion planting with hot peppers won’t work but creating a spray will:
- Bring 8 cups of water to a boil
- Add in 1-2 hot peppers (think cayenne or ghost peppers) chopped
- Reduce the heat and let cook for 15 minutes
- Remove from heat and let the mixture cool completely
- (Optional) Let the mixture steep for an entire day
- Strain mixture into a spray bottle.
Be careful when spraying your mixture. Don’t spray directly on edible fruits or vegetables. Instead, spray the leaves or stalk of the plant. Be sure to spray a small area first to make sure it doesn’t adversely affect your adored plants!
Aphids are sneaky and like to hide on the underside of leaves, so be sure to spray both sides of your plant’s leaves.
Peppermint, Thyme, and Rosemary Repel Aphids
Peppermint is in a ton of products we use, from toothpaste to candies and desserts. We might like it, but aphids don’t enjoy the strong scent of peppermint.
Thyme and rosemary are also very aromatic spices and plants that aphids tend to avoid and shy away from.
Peppermint, thyme, and rosemary are such strong scents that they mess with an aphid’s own sense of smell. This is why they’re likely to stay away from anything with a minty fresh scent or a very aromatic scent. Planting peppermint, thyme, or rosemary plants in your garden can be your first line of defense against those pesky aphids. Plant them next to plants you want to protect from aphids.
An aphid depends on its sense of smell to survive, and they will avoid areas where strong scents and smells are present.
Another option is to use an essential oil like Handcraft’s Peppermint Essential Oil. Place 10-15 drops of essential oil for every 1 cup of water into a spray bottle and spray away in your garden near aphid infestations! Thyme and rosemary also come in essential oil form.
Commercial products are another option. Mighty Mint Insect and Pest Control Peppermint Oil comes in a ready-to-use bottle. Peppermint is the #1 ingredient, and there’s no need to dilute the mixture – it’s ready as soon as your mailman drops it off!
Aphids Hate Neem Oil
Neem oil is found in the seeds of the neem tree, native to South Asia. This oil has a sulfuric and garlicky scent, which aphids find revolting.
Products like Bonide Ready-to-Use Neem Oil are perfect for your garden. The good news is that neem oil is not harmful to the good guys – bees and other pollinators.
The toxic effects of neem oil only happen if ingested by bugs, so be sure to spray only on the leaves of your plants. This is the most likely area where aphids will be chowing down.
Be sure to always follow the label and directions on any products for proper application. This may need to be reapplied often to remain effective.
Use Chives And Garlic To Repel Aphids
Garlic and chives are two more plant smells you can load in your arsenal of aphid-repelling scents.
The smell of garlic and chives in the kitchen may be appetizing to us, but to an aphid, the powerful smell masks other scents they need to survive, like alarm pheromones that warn them of predators.
You can plant garlic and chives to help repel aphids from your garden, but you’ll want to crush the leaves every once in a while to help release the scent of the plant. Like hot pepper plants, aphids won’t be repelled simply by the presence of the plant.
For garlic, you can also opt for a homemade spray from essential oils like Plant Guru’s Garlic Essential Oil. Add 10-15 drops per 1 cup of water and place in a spray bottle.
If you’d rather not make your own, consider buying a pre-made product like Mama Nature’s Mosquito Juice. Don’t let the name fool you – this product’s #1 ingredient is garlic, which repels aphids! Just be sure to follow the directions on the label, as this product must first be diluted before using.
An additional option for chives would be to buy bulk dried chives and soak them in water for 24 hours. Add the mixture to a spray bottle and add 1tbsp of liquid soap to help it stick to the leaves of your garden plants.
Use The Scent Of Marigolds, Petunias, And Nasturtiums To Repel Aphids
If you’ve ever wanted a more natural way to repel aphids, this is it! While aphids love most plants, they don’t love ALL plants. Marigolds, petunias, and nasturtiums, in particular, seem to be an aphid’s least favorite buffet item.
Despite what we may think, fragrant plants aren’t always fragrant. A chemical reaction occurs every day at certain times to increase the smell of the flower. This is to attract pollinators like bees.
So, what exactly does THAT mean?
Make sure you have pollinators, or the scent of these flowers will be far less effective at repelling aphids. Marigolds, petunias, and nasturtiums all need pollinators to reproduce, so you must have bees, butterflies, hummingbirds, or even lady beetles around who can pollinate the flowers. The fragrance of these plants keeps aphids away.
This will ensure they release their fragrance daily, meaning way less work for you!
You can use all three plants or pick your favorite. Simply plant them in your garden alongside the plants you want to protect. Remember, all three of these are annuals, so they will need to be replanted every year. But it sure is worth it!
Aphids Are Afraid Of Mums
A bug being afraid of a plant? Come on…but it’s true! Mums are short for chrysanthemum, which typically come out in the fall and are planted annually. With care, they can be perennials, especially in warmer climates
Mums have a two-fold defense system for aphids. Firstly, they contain a chemical called pyrethrum. If it sounds familiar, that’s because it’s found in a ton of insecticidal products like shampoos and skin repellents.
This natural ingredient in the mum is a repellent for aphids, along with a host of other pest insects.
A mum’s second defense system was found in a 2019 study. Scientists found that mums actually produce a scent that mimics an aphid’s alarm pheromone. This pheromone is used to warn other aphids that a predator is nearby and to stay away!
This mimic scent has a dual purpose on its own: it both repels aphids and attracts their predators. Once those parasitic wasps or lady beetles catch a whiff of the alarm pheromone, they’re likely to pounce on the area and scour it for any remaining aphids.
Other Ways To Repel Aphids
Using scent deterrents is an excellent way to prevent aphids from colonizing your entire garden. However, sometimes scent repellents alone aren’t enough. Here are a few other things you can do to help control those pesky aphids.
A quick note, you can check out our full list of the best aphid repellents here.
Use Your Garden Hose
Aphids aren’t like spiderman. They won’t cling on and stick to leaves like glue. You have to water your plants anyway; why not take an extra step and try spraying some of the aphids off?
Make sure your hose is set to a stream that won’t harm any delicate plants or leaves. Gently turn the leaves of your plants over and spray them with water to remove aphids.
Depending on the size of your garden, this could be a daunting task. If you can’t get to every plant, focus on the ones that show signs of aphid feeding and focus on the nearby plants as well.
Encourage Natural Predators
You may not be thrilled to hear that an aphid’s number one enemy is a wasp. The good news is, this parasitic wasp does not sting people.
Parasitic wasps lay their eggs inside aphids, eventually killing them. Gross, I know, but bear with me. Once the eggs of the wasp hatch, those wasps also feed on aphids.
Lacewings, lady beetles, and soldier beetles are also big consumers of aphids. Lady beetles may be easy to identify, but others not so much. Do some research on what these insects look like and if you see one, instead of whacking it, leave it be so it can hunt down some aphids!
Generalist predators – those that don’t eat specific diets and might eat aphids – don’t typically go for aphids as they are not nutritionally dense. So be sure to encourage the predators that do eat aphids to stick around.
Wrapping Things Up
Aphids can be quite an annoyance in your garden or around your ornamental trees and fruits. They reproduce rapidly, growing their colony to colossal numbers in a short time. The best way to repel them is to take preventative measures.
Scents and smells will deter established aphid colonies from traveling to other plants in your garden. To recap, the 11 scents and smells that deter aphids include:
- Neem oil
If you’re having a really tough time getting rid of your aphids, you can always ask for help from a professional! Our nationwide pest control finder can get you in contact with a professional for free.
With any scent deterrent, persistence is key. Be sure to keep applying the scent often to remain effective so you can be rid of those aphids for good!
Hu, H., Li, J., Delatte, T., Vervoort, J., Gao, L., Verstappen, F., Xiong, W., Gan, J., Jongsma, M. A., & Wang, C. (2018). Modification of chrysanthemum odor and taste with chrysanthemol synthase induces strong dual resistance against cotton aphids. Plant biotechnology journal, 16(8), 1434–1445.
Li, J., Hu, H., Mao, J., Yu, L., Stoopen, G., Wang, M., Mumm, R., de Ruijter, N.C.A., Dicke, M., Jongsma, M.A. and Wang, C. (2019), Defense of pyrethrum flowers: repelling herbivores and recruiting carnivores by producing aphid alarm pheromone. New Phytol, 223: 1607-1620.
Toft, S. (2005). The quality of aphids as food for generalist predators: implications for natural control of aphids. Entomology, 102, 371-383.
Van Emden, H. F., & Harrington, R. (2017). Aphids as Crop Pests (2nd ed.). CABI.