Frankincense, also known as olibanum, is an aromatic resin harvested from Boswellia trees, primarily grown in Africa and the Arabian Peninsula. The resin is collected by “tapping” the tree bark, causing the sap to bleed out and harden into “tears.” Historically, frankincense has been a highly valued commodity used in religious ceremonies, perfumes, and traditional medicine for thousands of years. Its distinct, woody, and spicy scent has led to the belief that it can deter insects, a claim modern science is now evaluating.
Scientific Evaluation of Repellent Properties
The efficacy of frankincense as an insect repellent depends heavily on the preparation method, particularly whether the essential oil or the resin smoke is used. The essential oil, steam-distilled from the resin, has demonstrated both repellent and insecticidal properties against various pest species. Studies have shown frankincense essential oil possesses significant toxicity against the larvae of the southern house mosquito, Culex quinquefasciatus, and adults of the common house fly, Musca domestica.
The oil has also shown strong anti-insect activity against specific agricultural pests, such as the spiny bollworm, Earias insulana, and the hollyhock seed beetle, O. lavaterae. In laboratory settings, a 100% concentration of frankincense essential oil resulted in a complete knockdown effect against the beetle species O. lavaterae. Furthermore, when incorporated into specialized microcapsule formulations and applied to cotton fabric, frankincense oil achieved 100% mosquito repellency in testing.
Burning the frankincense resin produces aromatic smoke, a method utilized historically by the Egyptians to repel wheat moths in grain silos. Burning the resin releases volatile compounds into the air that flying insects often avoid. While the results are promising, the duration of frankincense’s repellent effect is shorter than that of synthetic commercial products, requiring more frequent use for continuous protection.
Chemical Components Driving Insect Avoidance
The anti-insect properties of frankincense are attributed to its complex chemical profile, which is dominated by organic molecules known as monoterpenes. Frankincense essential oil can contain up to 75% monoterpenes, which are highly volatile and contribute to the resin’s powerful aroma. These compounds interfere with the insects’ olfactory systems, effectively masking the scents that draw them to humans or food sources.
The most prominent monoterpenes identified in frankincense oil include alpha-pinene, limonene, and alpha-thujene. These components are also found in other plant-based repellents. These volatile chemicals are the tree’s natural defense mechanism against pests, and the extracted essential oil concentrates this protective effect.
The specific concentration and ratio of these monoterpenes are responsible for the oil’s effectiveness against various insects. The strong, resinous scent acts as a natural deterrent, signaling to pests that the area is unsuitable for feeding or breeding. This chemical composition grants frankincense the dual function of both repelling and, at high concentrations, acting as an insecticide.
Safe Application Methods for Repelling Pests
Frankincense can be used in two primary ways for pest control: as an essential oil or by burning the raw resin. When using the essential oil for topical application on the skin, dilution with a carrier oil is mandatory to prevent irritation or sensitization. A common dilution ratio involves mixing a few drops of frankincense oil into a teaspoon of carrier oil, such as coconut or jojoba oil, before applying it to exposed skin.
For non-topical application, the essential oil can be diffused indoors using an electric diffuser, which disperses the volatile monoterpenes to deter airborne insects. Alternatively, a homemade spray can be created by adding up to 40 drops of the essential oil to a small spray bottle containing water and witch hazel. This mixture must be shaken well before each use, and reapplication is necessary every hour or so for continued efficacy due to the oil’s volatility.
For those who prefer the traditional method, burning a small piece of the raw frankincense resin on a charcoal disc releases aromatic smoke that deters flying pests. This method should only be performed in well-ventilated areas to avoid excessive smoke inhalation. Frankincense essential oil should never be ingested, and any topical application should first be tested on a small skin patch.