Essential Oils and Botanicals
Over the next year, we will be writing several posts that focus on the myths surrounding DIY pest control. There are several interesting topics on the slate and for this post we will be addressing the use of essential oils to control pests. Essential oil(s) can be defined as any volatile oil(s) that have strong aromatic components and that give distinctive odor, flavor or scent to a plant. With regards to pest control, there are several articles that can be found on the internet (particularly Pinterest) which would have you believe that there’s an essential oil cure for any pest. These articles/methods can be very appealing as they promise success through using a natural and safe solution. While essential oils do have productive uses, there are several reasons why essential oils don’t always work well for controlling pests. Homeowners, many of them desperate to get rid of the pests plaguing their home, end up wasting precious time and money on essential oil-based, DIY pest control.
Several articles have claimed that peppermint (Mentha peperita) oil can be used to get rid of mice. The recommendation is to put peppermint oil on cotton balls and scatter them around your house where mice tend to enter. The articles also advise you to re-apply the peppermint oil regularly, as the smell dissipates quickly. So, why peppermint oil? The authors of these articles claim that peppermint oil is overwhelming and confusing to mice and acts as a deterrent. However, there is no scientific evidence supporting this claim. Peppermint oil will not deter mice, nor will it get rid of mice already living inside your home. At most, it will cause them to move to another location within your home. Also, peppermint oil is toxic to cats, whose livers are unable to metabolize some of the compounds in the essential oil. If exposed to peppermint oil (either orally or topically), cats can suffer symptoms that include drooling, vomiting, respiratory distress, and even liver failure. Unfortunately, as the popularity of essential oils rises, veterinarians have reported increased rates of poisoning.
Another common article found about DIY pest control is the use of tea tree (Melaleuca alternifolia) oil to kill bed bugs. The recommended method of using tea tree oil to combat bed bugs is diluting 20 drops of oil in a spray bottle and spraying the bed sheets. This simple approach is, unfortunately, ineffective. Bed bugs may only be killed by direct contact with undiluted tea tree oil, which is harmful to humans. Furthermore, in a bed bug infestation, there can be hundreds of bed bugs harboring in your mattress, furniture, and even walls well out of sight. If you were to kill every bed bug you saw with tea tree oil, there would still be many more hiding from you.
However, there are several essential oils whose properties have had success in controlling pests. Citronella (Cymbopogon nardus) essential oil has been used for over fifty years both as an insect repellent and an animal repellent. I am sure that many of you have observed this by utilizing citronella candles in your yard to help repel mosquitoes. While peppermint oil will not deter rodents, it will repel ants, lice, moths, and flies. Spearmint (Mentha spicata) and basil (Ocimum basilicum) are also effective in warding off flies. Catnip (Nepeta cateria) essential oil is also highly effective for repelling mosquitoes, bees and other flying insects.
Nevertheless, it is difficult to always rely on essential oils as pesticides due to lethal effects on insect pest species varying widely. The quality of essential oil is influenced by geography, weather, how was the plant was stored and packaged, along with many other factors. Each plant is unique, and it’s not possible to create the same oil every time to where products perform consistently. Also, essential oils require greater application rates and need frequent reapplication when used outdoors. Lastly, the efficacy of these materials falls short when compared to synthetic pesticides and/or treatments conducted by pest management professionals. While you may be able to successfully get rid of a few pesky insects with essential oils, it is not effective for all insects or an infestation occurring in your home.