While both scenarios present a set of challenges (in the supermarket: beating the weekend rush, using coupons before their expiration dates, enduring the dreadful parking lots, etc.), wild food foraging can seem to pose the more immediate threats (misidentification, embracing the elements of nature, etc.).
One of the challenges of being a wild food enthusiast in Pennsylvania is exposure to ticks. These small arachnids, particularly the deer ticks (i.e. blacklegged ticks), are no small threats, as they are vectors for illnesses including Lyme disease, ehrlichiosis, and anaplasmosis.
Typical precautionary measures include wearing long sleeved pants and shirts, wearing light colored clothing to easily spot the presence of ticks, and using repellents.
But which repellents are effective and safe?
DEET is one of the most popular tick repellents, yet researchers question its safety not only on human health, but on the health of the environment as well (1). Permethrin is another synthetic repellent recommended for protection against ticks, and even though it is indicated for topical application, the EPA classifies this insecticide as a weak carcinogen with toxic effects on fish and aquatic invertebrates (2).
Fortunately, researchers have analyzed alternative (i.e. more natural) ways to protect oneself against deer ticks. Let’s take a look at some of them:
An extract of Alaska cypress (Cupressus nootkatensis) has been shown to be effective at killing nymphal ticks, with effects lasting up to 21 days after treatment (3). This is important, for the reason that most humans are infected through the bites of these small and barely detectable nymphs.
Chinese weeping cypress (Cupressus funebris) has also been shown to effectively repel deer tick nymphs.
Junipers are coniferous plants in the cypress family (Cupressaceae). The same study that analyzed the repellent activity of Alaska cypress found that an extract of Eastern red cedar (Juniperus virginiana) was effective at repelling larval ticks.
Additionally, the oils of common juniper leaves (Juniperus communis) and Chinese juniper wood (Juniperus chinensis) are effective repellents against deer tick nymphs. In one particular study, common juniper leaf oil was just as effective as DEET (4).
Balsam torchwood (Amyris balsamifera) is an aromatic bush whose oil has been used traditionally as an antiseptic. An essential oil from the plant has been researched and shown to be an effective deer tick repellent (5).
Osage orange (Maclura pomifera) is a small tree in the mulberry family known for its “monkey ball” fruits. In the same study that analyzed balsam torchwood’s activity against ticks, researchers found that a primary constituent of the essential oil of Osage orange, known as elemol, effectively repelled deer ticks.
The compound isolongifolenone, derived from this Neotropical tree (Humiria balsamifera), has been shown to be an effective insect repellent. In one study, isolongifolenone repelled deer ticks as effectively as DEET (6).
Geraniol is the main compound found in the oils of rose, palmarosa, and citronella. It is also a component of geranium oil and lemon oil. As part of a plant based repellent, geraniol has been shown to be effective against deer ticks (7).
Lemon eucalyptus (Corymbia citriodora) is an Australian tree whose oil contains a compound known as menthoglycol. While no research has looked at its effect on deer ticks, a prospective cross-over field trial showed that application of the oil reduced the number of castor bean ticks attached to human participants by about 63% (8). The castor bean tick is a European hard-bodied tick that, like the deer tick, can transmit the bacteria responsible for Lyme disease.
And there we have it: 7 natural tick repellents that have been scientifically researched for their effectiveness. Many products derived from the aforementioned plants can be found commercially (i.e. sprays, creams, essential oils).
If you live in an area known to be at high risk of acquiring Lyme disease (check out this U.S. map to see if you are), consider implementing safe, yet effective strategies to protect yourself during your time spent in the wild.
Of course, there are many more plants that have the ability to repel ticks; if you have a particular strategy that works well for you, please share with us!