Why Can Lavender Repel Moths?
Linalool is a common ingredient in fragrances, but the only mention of it having a repellent effect was on mosquitos, not moths. Other fragrance compounds, such as the aptly called lavandulol and lavandulyl acetate, were also found to be unsuccessful at repelling moths. These are not the only compounds that contribute to lavender’s aroma; the essential oil of lavender is made of over 300 different compounds. Many may not even contribute to the scent at all, but that doesn’t mean they’re not responsible for the moth repelling properties. As it so happens, that is exactly the case in this situation.
A pair of tiny bags of dried lavender hang alongside our clothing in the wardrobes of our apartment. We keep them there, like many other people do, to keep moths away from our clothing, However, I realized a few weeks ago that, in the midst of conversation, that I had no idea whether there was actual science behind the belief that lavender is effective at repelling moths at all. So, like any good scientist, I set out to see if lavender actually did possess anti-moth properties or is just an old wife’s tale, entirely devoid of scientifically backed evidence.
A good place to start was to look into the compounds that make up lavender’s chemical composition. After all, it’s likely that it is one of these compounds that is keeping the moths at bay. Linalool and a closely related chemical, linalyl acetate, are the primary components of lavender’s fragrance. Linalool is a common ingredient in fragrances and personal care items, but the only mention of it having a repellent effect that I could find was on mosquitos, not moths. Other fragrance compounds, such as the aptly called lavandulol and lavandulyl acetate, were also found to be unsuccessful at repelling moths.
These are certainly not the only compounds that contribute to lavender’s aroma; the essential oil of lavender is actually made up of over 300 different compounds. Many may not even contribute to the scent at all, but that does not mean they are not responsible for the moth repelling properties of the plant. As it so happens, that is exactly the case in this situation.
The terpene family includes the components listed above, as well as a host of other fragrance compounds found in lavender. 1,8-cineole and camphor, two such compounds present in lavender, tend to be important contributors to the plant’s ability to repel moths. Other terpenes with insecticidal properties include alpha-pinene, found in conifers, and camphene found in rosemary, which contains both 1,8-cineole and camphor, but with a lower repelling effect than lavender.
Given that chemical evidence, you might be wondering about mothballs? These have been utilized for ages and done so due to the toxic nature (for moths) of the chemicals they release as they evaporate being toxic to moths. Unlike lavender, the reason mothballs are effective is clearly known. Naphthalene was a component in older mothballs, but 1,4-dichlorobenzene is used in the contemporary variety. As these chemicals slowly evaporate from mothballs, they assist in moth deterrence.
However, scientists have recently expressed concern with both naphthalene and 1,4-dichlorobenzene as both are unclear about the effects of their prolonged exposure to humans. The more these compounds are reviewed by the increasingly concerned scientific community, the more countries are actively pulling these off the market, with multiple EU countries banning the use of naphthalene altogether. Luckily, dried lavender provides another effective method of repelling moths from our clothing.