The main insect repellent essential oils are citronella, lemon eucalyptus, lemongrass and peppermint, however different creatures respond to essential oils in different ways, due to whether the plant feels that insects can be of any use to it or not. Today we’re looking at some of the extraordinary research done into insect repellent essential oils and at the end, I’ll share a couple of DIY recipes.
I don’t think I’ll ever forget the day our Managing Director, Jake asked me about insect repellent essential oils. The timing was pretty amazing really, because I was in the middle of writing my book about Melissa essential oil. Melissa means bee, and beekeepers use Melissa (lemon balm) to attract swarms. I was up to my armpits in data about how plants communicate with insects and, truth be known, I was pretty chuffed when he asked how much I knew. I bet no-one's smugness ever dissipated as quickly as mine did that day, when he replied “ Ok so that essential oils used for bug repellent covered, so and what about getting rid of iguanas? I wish someone had been videoing me, because my crash down to Earth must have been a picture. Needless to say, iguana’s aren’t something you need to think about much when you live on the border of England and Wales.
The great thing about my job is you collect so much information about so many things. I have an encyclopedic knowledge of stuff about funerary practices of Ancient Egypt, and now, if for some strange reason an iguana were to stroll up my path, I would also know what to do. But, every bit of this Wisdom Keepers herbal knowledge has been hard won. It culminated in VINEVIDA having a superset of insect repellents for sale, of course.
Are There Really Insect Repellent Essential Oils?
Is it just another bit of hype about things that essential oils can do? Because, let’s be honest, there is plenty of that around! It’s a valid question. You know, it’s even something I asked myself at one time. Well, you know, this is one of the topics I love most in aromatherapy, how plants interact with the outside world. Because in case you haven’t realized it yet, when you smell an essential oil, what you are actually doing is eavesdropping on a conversation between the insect and plant kingdoms.
Let’s just go back to Melissa for a moment, because that is a great way in.
Why Do You Use Melissa Essential Oil To Attract Bee Swarms?
Bees respond to it because it smells exactly like a pheromone called Nasonov that the bees secrete to say something akin to “Follow Me”. Bees use Nasonovit to show new flying bees the way back to their hive on their first training flights, and to mark the location of a new home for their swarm when it leaves their hive.
Hence, when scout bees are out foraging, they smell Melissa and think, “Wait, what…? Some other bee has marked that as a new home…we don’t want to be missing out!” . Honey bees, in particular, are inquisitive creatures always on the lookout for somewhere cool to go when the colony reproduces, so they nip in to take a look around. (If there is already a colony in there, they will have to get past the guard bees, who will demand they at least have pollen to pay their way, so if there is no welcome at the entrance that immediately tells them this is a vacant hive).
Within a couple of days, the smell is stronger, only this time, it smells like the Melissa plant, but it’s no. It’s the bees marking the hive with Nasonov.
Follow Me…This is Home, Smells Exactly Like Melissa Essential Oil
When the swarm arrives, you may have seen them collecting somewhere in a ball? Then, scout bees come back and forth from the hive, back to the colony ball, signaling why they believe their spot they have found is the best place to go. Everything that happens in the hive is democracy. They will stay in that ball until everyone is in agreement that this is a good choice. As each bee comes and makes her mark (this is women’s work, by the way) the smell gets stronger until all the scouts agree and then they move in. It’s incredibly fast. From marking a hive to getting a swarm takes about a week. (Although, it is usually finding an old piece of comb where brood bees have been hatched that is often the secret ingredient).
Come Hither, My Little Pretties
So, you might ask, why is it significant that the Lemon Balm plant smell the same as the bee pheromone.
Well, here’s the thing, it’s not just honey bees that communicate that way. Lots of solitary bees do too, including little mason and leaf cutter bees. If you are not familiar, they look like little bumble bees, usually with ginger bums and these are the main pollinators of the Lemon Balm.
They land on the plant that copies their smell to find out why it’s asking them to “Follow me”, they smell its delicious nectar, and discern its pollen and what happens then?
They dive in to have have sex…
Yes. You read that right.
Only the Queen Bee and the drones have bee sex. Worker bees, or as I like to call them, the sisters, foraging in flowers are actually the reproductive agents of the plants. They carry pollen - which is essentially the plants semen, and then deposit it into the female sexual orifice of another plant. (Actually plants even have ways of ensuring they can’t self pollinate too, but that’s a description for another day.)
Melissa smells like bees, because she needs bees to pollinate her.
And that is the secret to understanding insect repellent essential oils to know that plants talk to insects and animals through the chemicals that make the smells that we enjoy.
Bees Love Melissa
There is enough literature available to tell you that if you wear melissa essential oil a bee is less likely to sting you, but personal experience says they only really do that if honey bees think you are a threat. They are brave little warriors so if you are in their space enough to be that annoyed, they will still sting you to protect their sisters. Put melissa oil on a sting (in a lotion) it does heal much faster.
Bumble bees and little carder bees in particular really enjoy hanging out with a human who smells of melissa. You may find they try to sit on you, which I love, but that’s not what you came here to find, is it?
You want to know about insect repellent essential oils
Why Are Essential Oils So Effective as Bug Repellents?
If you imagine that a plant has roots and is anchored to the spot, it has no way to get out of the fierce sun's rays, or to run away from a massive iguana that’s planning to consume it alive. So, it makes these chemicals. Sometimes, they are to attract pollinators as I’ve said, but other times, it might be to make its leaves taste nasty.
Often a plant generates the chemicals to help it to heal after it has been overly nibbled, or to stop any other plants from germinating close by that could steal its nutrients. We can see how, actually, sitting very quietly, plants are their own stationary weapons factories.
Now, when we think of it like that, we can see how, what humans have appropriated as luxury perfumes, are in fact natural pesticides. These are what animals already naturally interact with. The chemicals that plants make to protect themselves are what we use as insect repellent essential oils.
What to Look for in EOs Natural Insect Repellents
I think it’s fair to say there are three key insect repellent essential oils. These are eucalyptus citriodora, citronella and peppermint. As you’ll see over the next few paragraphs, they are not the only ones, but these do come up time and again as being the most antisocial towards bugs.
Looking at the science behind insect repellent essential oils is fascinating. Take Eucalyptus citriodora, for example. Studies show that it does attract some species to pollinate it - but eighteen species to be exact - it has now evolved to be wind pollinated, releasing its pollen into the air by day. (Battacharya, 2005). This is clearly a good strategy for it, since so many insects prefer to stay away.
How to Use Essential Oils as an Insect Repellent
Choice of essential oils aside for a moment, an important factor in understanding how to use them is to think about how the plants use the volatiles. They release them into the air, allowing them to evaporate. The same is true of essential oils. Most of the main insect repellent essential oils are what perfumers call top notes. That is they have small molecules and you smell them quickly because they release into their air fast. Clearly this would be a good strategy for a plant. Get rid of the beggars fast! The problem is that unless we have a fixative, they evaporate…then they are gone.
There are some good base notes that work well, like vetiver and patchouli, but for the most part, you are either going to want to use an alcohol fixative, or to re-apply your oils every two to three hours.
I find lotions and sprays make the best insect repellents, and don’t forget about candles too.
Safety of EOs as Repellents
In addition, insect repellent essential oils like citronella can be skin irritants, especially if they are oxidized, because they are a little older. Always buy a new bottle of citronella to use, and use very small dilutions, especially if you are going to use them on young skins.
Also, please remember that whilst essential oils do not have side effects, they do have many main effects.
Have a quick run down in your head of what else an oil might do.
Remember that eucalyptus slows respiration, for example, so that would not be safe to use on young children, except for on their backs.
Please don’t be tempted to spray it around a pram or a crib, for example.
In the same way, ylang ylang would not be a great plan for someone who has low blood pressure either.
As in all cases, we do not recommend using essential oils, topically, in the first 16 weeks of pregnancy. However, I think you’d be fairly safe with the odd spritz of spray around you.
Essential Oils To Repel Wasps
Your best ally is going to be citronella for both bees and wasps, which is very strange when you think how similar it smells to lemongrass and Melissa essential oils.
As well as using insect repellent essential oils, you could also try luring wasps away from where you are sitting. Put a bowl of strawberry jelly down the bottom of the garden, away from where you’re sitting and where the children play. They are hungry for sugar so if you provide them with what they want, they’ll have no reason to chase the kids’ lemonade.
Essential Oils to Repel Ants
So, ants are one of those species that we can live perfectly happily with, until we don’t.
When they are outside, it should really be a case of out of sight out of mind, but if you find them in your house, then potentially they are after food. They steal supplies and anything left behind is spoiled. Likewise, for a short period each year, they gain wings and head off on their mating flight and so there are these vile swarms everywhere. Horrible.
Ants are one of the most prolific creatures on the planet and a massive genus. Their global population is estimated to be somewhere between 10 and 100 quadrillion! Believe it or not there are over 13,800 species known across the planet, with about 1000 of them over there with you in the USA.
Whilst they might all look similar, they do have quite differing habits.
Carpenter ants for example are second only to termites in terms of destruction potential. They create mayhem by chewing and tunneling inside moist wood to make their nests. You might have seens some of the telltale signs like bits of insulation or sawdust shavings scattered around.
Or Fire ants, notorious for their sting that can trigger allergic reactions.
But we do need ants. They are important creatures in our ecosystem. They turn and aerate the soil and help water and oxygen to reach the roots of plants. They take seeds down into their tunnels to eat, then their waste provides food for many different organisms. We value them but we don’t want them destroying the patio or raiding the kitchen.
Now ant research is really big in China believe it or not, and they have done lots of work with eugenol from clove oil and menthols in mints. They did a fascinating experiment with fire, ants that showed when they put clove powder down, 3 hours ours later 99% of the ants had gone and any left at 6 hours had died. Most of them had the sense to simply get out of the way.
There was another great study, published last year by the University of Maine. Their study focussed on red ants and they compared the effects of using neem oil, d-limonene, which is a constituent you’d find in citrus oils mainly, spearmint and peppermint essential oils. The neem and limonene were impressive and repelled the ants for upto 3 weeks, but the reason I choose to recommend peppermint oil for bugs is because they continued to repel the insects right through the experiment which was for a massive 15 weeks long. (Bernard, 2020).
Methyl salicylate also stops them from digging. From an outsider's point of view, that is fascinating. I wonder if it seems too cold for them, or if they somehow fear how vigorously it would thin their blood, which is what it does to humans, of course. Wintergreen essential oil is almost 95% methyl salicylate. (Chien, 2019) Menthol and euganol also stop the digging, menthol is also cold, and eugenol feels hot.
What’s interesting is one of the best results seen in any of the experiments was using patchouli, which has always been a traditional solution in Asia, and indeed Patchouli killed all of the ants it came into contact with (Albequerque, 2013)
Interestingly the government has a list of acceptable ingredients you can and can’t use in commercial preparations. Patchouli isn’t on the list of acceptable ingredients, and I wonder if that’s because it was too effective. After all, we can’t go round killing whole colonies can we?
Again, although it doesn’t smell like it, patchouli is another member of the mint family.
Essential Oils To Repel Bedbugs
I don’t think I need to go into the nuts and bolts of why we don’t want these horrible little things, again, they actually don’t like many essential oils. However, trials show they don’t like to land anywhere where they can smell the constituent geraniol and that rosemary oil will kill them. (Feldlaufer, 2015)
Geraniol is a prevalent constituent of lemon, ginger, nutmeg, lavender, lime, orange, and rose. It is the main constituent of geranium and palmarosa essential oils and is also found in large quantities in lemongrass oil.
Bleuch, the less said about bedbugs the better.
Let’s move on.
Ok. I’ll admit. This is not much better. As soon as you start thinking about this you’re going to start itching. We’ve got chamomile for that vile bit of psychology!
But the challenges of making something for head lice, aren’t really in the essential oils because there is tons of research, tons of studies and volumes full of proof of how to deal with both head lice and their eggs, the nits.
The bigger challenge is that we’re not spraying concrete to get rid of ants, this is a treatment to go on delicate kids’ heads. And probably small kids, because as every good mother knows, nit heaven is in the primary school classroom. Little one’s playing together, huddling in corners, lolling on each other in story time, it’s just great. Even the laziest louse can just casually stroll from one head to another.
A female louse will lay about 10 eggs every day. Research shows that both lavender and tea tree kill almost half of those. (Barker, 2011)
Obviously the longer you use the preparation and with a combination of good combing, you can eventually get on top of the problem. Tea tree is an insect repellent essential oil, from the pure point of view that lice don’t seem to like its smell. Hopefully that will also reduce the number of infestations you have.
It goes from heinous to abhorrent, doesn’t it? Lice to roaches.
It’s so interesting to read some of the research though because it really tells a hidden story of the world that we as humans wouldn’t really perceive, or we take for granted. First, the eucalyptus tree is an incredibly healing plant that has evolved in some of the most challenging conditions on the planet. It grows in desert land and it grows in tropics. It’s adapted its needs for water, but it’s also created this raft of chemicals to deal with threats from insects, predators and germs.
There was a fantastic study, done by the Department of Plant Protection in Iran, where they tried different plant species against different insects.
Anopheles stephensi is a mosquito which is one of the most powerful vectors of Malaria in India, and you know what cockroaches are, of course. So this is a telling result. 2.2 minutes of exposure killed all the mosquitoes who encountered it, but cockroaches managed to endure 1403 minutes, (Zibaee, 2015) which, if your math needs a little help, is 23 hours and a few minutes to spare.
They do say that roaches are the most hardy species don’t they, and there's all these urban tales to say they can survive a nuclear blast, but what they can’t endure for more than a day, is being exposed to certain essential oils including eucalyptus.
To give a bit of perspective to this, VINEVIDA aren’t the only people developing these kinds of product lines. It’s a noble endeavor to want to reduce the number of chemicals we’re dispatching into the environment, but let’s be clear, these things need to actually work. This isn’t just an irritating buzzing fly we’re talking about here, it’s a carrier of one of the deadliest diseases known to man. According to the World Health Organization, mosquito bites result in the deaths of more than 1 million people every single year. Finding essential oils that repel mosquitoes is a very important quest.
So if you want proof of how excited people are by the fantastic results we’re seeing in the laboratories, try this for size.
Insect Repellent Essential Oils and Mosquitoes
The number of patents for mosquito repellents containing essential oils have almost doubled, every four years, since 1998. A 2011 review of the patent literature found that a third of all patents registered contained essential oils as their main ingredients. In over half of those, eucalyptus and citronella were the active components..
Both insect repellent essential oils have extraordinary abilities and perhaps it’s something to do with the lemony fragrance because Lemon Eucalyptus is especially useful as a deterrent. I think, at this point, scientists are in agreement that it is probably the best mosquito repellent. A study published by the Journal of American Mosquito Control compared the effects of lemon eucalyptus with the chemical repellent Deet. Deet provided 100% protection, but for three hours, lemon eucalyptus almost matched that, providing a massive 95% protection. And that three hours is an important factor of course, because after that the fragrance has evaporated, because there is no synthetic fixative, so we would have to reapply.
That said, in perfumery, the best fixative oil we have is beautiful thick, deep vetiver. But vetiver has repellent qualities of its own, so it’s the ideal oil to add to try to prolong that fragrance for as long as we can.
It’s the female mosquito that does most damage. She needs extra protein to lay her eggs, so she voraciously hunts human blood to supplement that. She likes to breed in stagnant water. In India, vetiver roots have been lowered into stagnant wells to clean the water for over 5000 years.
There is an ancient set of medical texts, which relate that you will rarely find mosquitoes where vetiver is growing. They just don’t like its fragrance. A study published in the Journal of Entomology in 2018 tested that claim, focussing on two specific chemicals vetiverol and isolongifolene. Even in isolation, separated from the rest of the constituents of the plants, these achieved upto 98% mortality of mosquitoes.
Again, too, even though there’s not much science to draw on at this point, I think I would agree with most internet pages around using peppermint oil for bugs.
Incidentally, last year I wrote a piece specifically around mosquitoes and essential oils for mosquito bites.
Essential Oils That Repel Ticks
Tics are a vital food source for lots of reptile life, but since they are such terrible vectors of disease, quite frankly they are in the most part, a nuisance to the mammal population. They may or may not be a problem to you depending on what area you live in and the pastimes you have, including paddling or where you walk your dog. Tics can be harmless, but they can also be dreadful spreaders of disease.
Most people will group tics with insects like mosquitoes and fleas, because they are blood feeders, but actually, since they have eight legs, they are arachnids.
Although both males and females are problematic, the outer shell of a male tic prevents him from expanding too much on a single meal, but a female requires copious amounts of blood to allow her to lay her eggs, and so these have a voracious appetite. Again, there are many different types of ticks, and each species will have their own eating habits which will determine how long they remain attached to you to feed. In some cases though they can take so much blood from a dog that they can make it deficient in certain minerals.
They attach themselves to the host animal and then secrete a kind of cement-like substance to secure them, then place a feeding tube into the host. Their saliva contains anesthetic properties, so the host is often unaware they are being robbed, until it’s too late. The main problem being that if the host has a bloodborne disease, then the tick will pass it from the first host to the next and next and so forth.
One particular problem is Lymes disease that can present as muscle pain, lethargy, dizziness, temperatures and rashes, and it can be very difficult to diagnose.
Insect Repellent Essential Oils Also Repel Tics
Presumably ticks don’t like strong smells at all, but it’s hard to know. A 2017 study done in Croatia tested a whole barrage of oils against the ticks and to be honest the critters didn’t seem to be particularly enamored with the smells of any of them. The ones the tics liked least were red thyme, lemon eucalyptus and clove again. Their study showed it repelled 91% of ticks in total. So not all of them, but nothing that a bit of vigilance couldn’t help.
Incidentally, that patchouli thing happened again. Experiments show it killed all of the ticks in the study, but again, we haven’t put it into the blend because it's not an accepted substance allowed in pesticides. But, we do sell patchouli essential oils so you might think that I’d suggest also buying some of that, and you might be right but I couldn’t possibly comment!
Beyond Insect Repellent Essential Oils… Who Else Do The Plants Have Issues With?
There are loads of other ways that plants engage with the world. Some release secondary metabolites (the correct terms for the essential oil before it gets distilled) to prevent other oils germinating near them, or even to recruit other creatures to see off the ones that are attacking it.
So, there aren’t just insect repellent essential oils…. Mice, rabbits, deer…they can all be rather too partial to a nibble on a leaf.
Essential Oils That Repel Rodents
You would not believe the amount of research there is into repelling rodents. But if you have ever had an infestation, I’m sure you get it. Rats in particular are shag-nastys with incredibly short gestation periods. They can have litters of upto 22 young, although eight or nine is more usual, and gestate for just 21 days. They can have upto 7 litters in a year, so you are looking at around 100 young from one female and that’s not counting their potential to interbreed.
If you enjoy feeding the birds, it’s almost certain that you’ll also be entertaining rats. They like to eat the food, but they are not fussy about what the food is, and are more than happy to feast on wires, cables or wood. They are also dreadful vectors of disease spreading all manner of bacteria, even down to the plague, of course! More likely though is Weils disease which can come from getting rat urine into scratches. If you put your hand into a pond, for example, you can be at risk from Weils.
We know extraordinary amounts about how essential oils affect rodents, because rats and mice form the basis for most experiments for human medicine, of course. They have incredibly powerful senses of smell and we know that they, like snakes, smell in stereo, which helps them to identify predators or food to an accuracy of about 1cm. Amazingly their affinity with smell is so strong they can be trained to sniff out landmines and to find cases of tuberculosis.
Constituents exist in mints that dampen rodent desires to mate and chemicals found in cinnamon do all manner of things to repel them. Some discourage them from gnawing, others depress their appetites and they hate cinnamon so much that it is classed as a repellent in its own right. Presumably, like we saw in snakes, they too are irritated by the fumes but that’s unclear.
Essential Oils to Get Rid of Moles
Moles make me laugh. There’s nothing horrible about them at all. They are the cutest little things, all small, blind and velvety, but then they create utter mayhem in the garden. The worst danger they bring is mental instability because they drive you insane!
Again, they hate menthol in mints and also castor oil.
Essential Oils to Get Rid of Slugs and Snails
So, the world of essential oils and slugs is a bonkers thing in its own right, because there are all these scientists, presumably in white coats, mooching around greenhouses, surrounded by cobwebs and dead spiders painting essential oils into the insides of their plant pots .
The outcome of which again is that various mints repel slugs and in some cases even kill them and constituents in clove oil kill snails. A massive boost for anyone who wants to save their cabbages but is worried about leaving slug pellets around by kids or pets. Likewise, if a bird happens to pick up a treated snail, there is no evidence that it will do the bird any harm either.
Essential Oils to Get Rid of Spiders
There is very little interesting to say about spiders except that they don't really seem to like strong smells so that gives you a massive range of tools to use to deter them. We chose a blend that smells nice and would seem at home around the ceiling of any house in September when they all decide to move in.
DIY: Essential Oil-Based Bug Repellent and Bug Bite Relief Blends
- 50ml Water
- 1 teaspoon Alcohol (Vodka works well)
- 10 drops Ylang Ylang Essential Oil (Cananga odorata)
- 3 drops Citronella Essential Oil (Cymbopogon nardus)
- 3 drops Lemon Eucalyptus (Corymbia citriodora)
Method of Preparation: Importantly, beware of using old oils in this recipe. The monoterpenes oxidize quickly and could cause skin sensitization. Disperse the essential oils into the alcohol then add to the water in a spritzer bottle.
Method of Use: Re spritz around you, every hour or so.
- 2oz Aqueous Cream (Buy it over the counter at the pharmacy)
- 10 drops Ylang Ylang Essential oil (Cananga odorata)
- 3 drops Citronella Essential oil (Cymbopogon nardus)
- 3 drops Patchouli Essential oil (Pogostemon cablin)
Method of Preparation: Importantly, beware of using old oils in this recipe. The monoterpenes oxidize quickly and could cause skin sensitization.
Method of Use: Smoothe over exposed skin. Reapply every two hours.
A Final Word on Insect Repellent Essential Oils
Remember, you are going to need to dilute your insect repellent, and to replenish them every couple of hours or so. If you want an easy way in of course, why not buy some of the Vinevida ready mixed preparations?