Tuesday, 23 June 2020

Natural and Effective Herbal Bug Repellents

Hartington, Derbyshire
Hartington, Derbyshire © Debs Cook

Out with Simon yesterday for a lovely walk along the Hartington stretch of the Tissington Trail, and we hadn't gone very far when Simon started swatting and flaying his arms about trying to deter some flying beastie from eating him. Luckily I was carrying some of my trusty home made Bug Busting Spray (recipe at end of this post) with me. Its one of those things I always carry in my bag in the warmer months of the year. A couple of squirts of the spray and he was no longer worried about the flying beasts that were troubling him moments before, after he'd been sprayed, you could visibly see the beasties flying away to avoid him, and he declared I 'rocked' lol!

Not everyone knows how to make their own bug busting spray, so they reach for sprays that contain things like DDT or other chemical nasties. All that you need is a few bottles of essential oils in your bug busting armoury and a carrier to ensure you get the irritating beasties to buzz off and leave you alone, so you can get on with enjoying the your summer walks, picnics or just sitting in the garden with a good book and a G&T!

Long before the advent of using man-made chemicals like DDT (dichloro-diphenyl-trichloroethane) which was first synthesised in the late 19th century, to eradicate bugs, man was using plant based products to deter them, we have plants that have natural chemicals in them which can be used to get rid of pests: -

Pyrethrum derived from the Dalmatian chrysanthemum (Tanacetum cinerariifolium) which contains a series of constituents called pyrethrins that attack the nervous systems of all insects, and inhibit female mosquitoes from biting.

Derris there are several plants in the Derris family that contain a compound called rotenone including the Tuba Root (Derris elliptica), and other roots from members of the derris family. Rotenone is a powerful broad-spectrum insecticide and fish poison, however the use of derris as an insecticide was banned by the EU back in 2010 due to its potential neurotoxicity.

Quassia comes from a small evergreen tropical shrub known as Bitter Ash (Quassia amara) it is another plant that was utilised for its insecticidal properties having been particularly effective dealing with aphids and  the Colorado potato beetle, the plant contains the compounds quassin and neoquassin which both have insecticidal properties.

Tobacco (Nicotiana tabacum) was used to provide the compound nicotine to make an insecticide until the late 20th century, at the end of WWII around 2,500 tons of nicotine were being used on crops to eradicate pests, but the use declined in the late 20th century due to the discovery that the effects of nicotine on on humans and livestock were poisonous.

The four plants above being now know to contain toxic components that were shown to be do more harm than good, not only to the environment but to our health as well, have been replaced by more environmentally friendly products in more recent history. If you’re a gardener you may be interested in my article on Herbal First Aid for the Garden which looks at using herbs to eradicate pests and diseases in the garden, many of those same herbs can be used to help protect us.

Over the past 10 years research has been carried out on the ability of using ‘plant extracts as potential mosquito larvicides’. The plants being tested include to eradicate mosquito larvae include:- Ashwaghanda, Eucalyptus, Holy Basil, Moringa, Orange, Pepper and Turmeric. In 2011 researchers in Thailand looked at the ‘Efficacy of herbal Essential Oils as Insecticide’, focusing on Sweet Basil, Citronella, Clove, Eucalyptus, Lemongrass, Orange and Ylang-Ylang essential oils, as a means of using their insecticidal properties to control three different types of insects, the Anopheles dirus, the bug species which plays a major role in malaria transmission. Culex quinquefasciatus aka the Southern House Mosquito and Aedes aegypti aka the Yellow Fever Mosquito, of the oils studied, the study concluded that lemongrass oil had the most potential “to be used as an insecticide against 3 species of mosquitoes”.

Wild Bergamot is among two Monarda plants that are being studied to act as a mosquito repellents, especially on the Yellow Fever Mosquito, a study conducted by the Department of Pharmacognosy, at the University of Mississippi in 2013 concluded that: - "Systematic bioassay-guided fractionation of essential oils of both Monarda species was performed to identify the active repellent compounds, and isolated pure compounds were individually tested for repellency. Of the isolated compounds, carvacrol, thymol, eugenol, and carvacrol methyl ether were found to be the repellent compounds. Active repellent compounds were also tested for larvicidal activity against 1-day-old Aedes aegypti larvae. Thymol was the best larvicide among the tested individual compounds (LD50 of 13.9 ppm)."

Rose Geranium Flower

Essential Oils with Bug Busting Properties

Horse Flies MidgesMosquitoes
Ticks
Citronella
Cedarwood
Eucalyptus
Lavender
Lemon
Lemongrass
Patchouli
Peppermint
Rose Geranium
Tea Tree
Thyme
Citronella
Eucalyptus
Lavender
Marjoram
Neem
Rose Geranium
Spearmint
Peppermint
Basil
Cinnamon
Citronella
Clove
Eucalyptus
Lavender
Lemon
Lemongrass
Melissa (Lemon Balm)
Peppermint
Rosemary
Rose Geranium
Thyme
Citronella
Eucalyptus
Grapefruit
Juniper Berry
Lavender
Marjoram
Peppermint
Rose Geranium
Thyme


Five of the Best Essential Oils that Naturally Repel Bugs

Scanning across the lists there are five oils common to eradicate all pests, these being Citronella, Eucalyptus, Geranium, Lavender and Peppermint oils, so having those 5 oils in your bug busting armoury will enable you to reduce the number of flying beasties that can make summer a misery.

1. Citronella – This oil is one of the most popular oils for keeping mosquitoes at bay because it has brilliant insect repelling properties, it contains citronellol, citral, citronellal, geraniol, nerol and the terpene ketone borneol which all add to the insect repelling properties of the oil. The geraniol in particular is a most effective plant-based mosquito repellent and is found in other oils including bergamot, jasmine, lemon, mandarin, melissa and rose. Oils like lemongrass and melissa can be used as a substitute if you don’t have any citronella oil, you can add citronella oil to candles and vaporisers’ outdoors to keep mosquitoes at bay, as well as using the oil is sprays for the body and surroundings.

2. Eucalyptus - Has natural insecticidal and anti-parasitic properties so can be added used in sprays to deter flying insects and pests, the oil has been studied as a repellent against the mosquito, in particular two of the constituents found in eucalyptus, namely p-menthane-3,8-diol and eucamol and whether they are as effective as DEET, in some cases the constituents found in eucalyptus were found to be more effective. The 1996 study conducted by the Department of Medical Parasitology, at the London School of Hygiene and Tropical Medicine concluded that “Repellents, applied to the legs and feet at doses chosen as used in practice, gave complete protection from biting for between 6 and 7.75 h, depending upon the formulation type, with no significant difference between PMD and deet in terms of efficacy and duration of protection.

3. Geranium – The oil of geranium is a well-known tick repellent, studies have also found it to be effective at eradicating head lice, the oil contains four major constituents: - citronellol (38%), geraniol (16%), citronellyl formate (10.4%), and linalool (6.45%) which are all have natural insecticidal properties. A study on the Insecticidal and Biting Deterrent Activity of Rose Scented Geranium Oils concluded that “rose-scented geranium essential oils and pure compounds from this study have shown promising results as insecticides, which warrants further research to establish them as potential biopesticides. One of the pure compounds, geranic acid, showed highest biting deterrent activity, which was statistically similar to that of DEET. Further research, through intensive in vivo bioassays, is needed to explore the possibility of using this compound as a deterrent/repellent in human protection.” Geraniol is found in the five oils we’ve selected here and as well as being kryptonite for ticks, it’s also a very effective plant-based mosquito repellent.

4. Lavender – This fragrant essential oil is most often associated with its ability to relax the mind and help to de-stress the body, but lavender is also a good oil for helping to banish bugs like flies, moths and mosquitoes. Ketones in lavender oil include camphor which acts as an natural repellent, and the oil has been used for its insecticidal and vermifuge use for centuries, during the medieval period water made from lavender flowers was used as a hair rinse to help prevent head lice and the herb was often scattered around the floors to prevent pests in the home such as moths, fleas and lice.

5. Peppermint - Another useful oil to have on hand is peppermint oil, it’s the arch nemesis of all the biting beasties in our table above, it’s also on the fly exclusion zone for house flies and fleas hate it, as do ants. A few years ago on a holiday in France, the cottage we were staying in was plagued with ants. I always take a basic herbal kit with me that contains a variety of herbal products which includes some essential oils and peppermint is one of those oils. I smeared the peppermint oil around the doors, windows and any other places the ants were getting in to the cottage and within an hour we saw a decrease in ant numbers, by day 3 there were NO ants getting in anywhere, and you could see them taking a wide berth to avoid the peppermint, result!

You can chose also to make your own special blends targeted at one specific insect using theessential oils listed in the table above, or make my Bug Busting Spray.

Mrs Cook's Bug Busting Spray

100ml Distilled Witch Hazel, Perfumers Alcohol or Vodka
10 Drops Citronella Essential Oil
10 Drops Eucalyptus Essential Oil
10 Drops Lemongrass Essential Oil
10 Drops Lavender Essential Oil
5 Drops Geranium Essential Oil
5 Drops Tea Tree Essential Oil
120ml Glass or Plastic Spray Bottle with Cap

Method: The spray is simplicity in itself to make, simply take a clean glass or plastic spray bottle large enough to hold 110ml of liquid, you can use plastic but sometimes essential oils can eat away at the plastic if left long term. Add the witch hazel to the bottle and add the essential oils to this. To use shake the spray bottle to make sure that all the essential oils are mixed in with your carrier solution and spray the bug repellent on to the skin.

N.B. I use perfumers alcohol to make my spray but this isn't so easy to obtain, so use Distilled Witch Hazel which should be available at a local chemist or pharmacy or failing that use Vodka instead, try to get one that is 100 proof, standard 80 proof (40% alcohol) is fine.

Disclaimer: Whilst every effort has been made to source the most up to date and accurate information, I cannot guarantee that remedies in my articles are effective, when in doubt, consult your GP or a qualified Medicinal Herbalist. Remember also that herbal remedies and essential oils can be dangerous under certain circumstances therefore you should always seek medical advice before self-treating with a home made remedy, especially if you are pregnant, breast feeding or suffer from any known illness which could be adversely affected by self-treatment.

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