Cloves, derived from the dried flower buds of the Syzygium aromaticum tree, are a common spice valued for their distinct aroma and flavor. They are traditionally used as a natural remedy for deterring insects.
The Active Compound and Its Effects
The primary compound responsible for the insect-repelling properties of cloves is eugenol, which typically constitutes 70% to 85% of clove oil’s composition. Eugenol works by interfering with the sensory receptors of insects, overwhelming their olfactory senses. This disruption makes it difficult for pests to locate hosts or food sources.
Eugenol also acts as a neurotoxin to many insects, affecting their nervous systems and potentially leading to paralysis or death upon direct contact. Scientific studies indicate that eugenol targets mitochondria within insect cells, inhibiting energy production and causing cell death.
Research supports the effectiveness of clove oil as an insect repellent. For example, a 10% clove oil solution demonstrated 100% repellency against Aedes aegypti mosquitoes for up to two hours in one study. Eugenol has shown repellent activity against various arthropods, including Aedes aegypti and Anopheles stephensi mosquitoes, triatomines, beetles, and ants. While eugenol is the major repellent compound, other components like eugenyl acetate in clove oil do not offer significant protection.
Using Cloves as a Repellent
Cloves and clove oil are used in several practical ways to deter insects. Whole cloves can be placed in problem areas, while clove essential oil is often used to create do-it-yourself (DIY) sprays. These sprays typically involve diluting clove oil with water or other carriers, and sometimes combining it with other essential oils like citronella or eucalyptus to extend its effectiveness. Diffusers or cotton balls soaked in clove oil can also release the scent into the air.
Laboratory tests suggest effectiveness against mosquitoes, sometimes comparable to synthetic repellents. Cloves are also commonly used against ants, mites, ticks, and spiders. American cockroaches are particularly vulnerable to clove bud essential oil, though German cockroaches may require higher doses for control. The strong aroma of clove oil can also help deter flies. Reapplication is often necessary, especially for outdoor use, as clove oil can break down quickly in the environment.
Safety and Limitations
While cloves offer a natural approach to insect repellency, important safety considerations exist, particularly with clove oil. Highly concentrated clove oil can cause skin irritation, including redness, itching, or a burning sensation, if applied directly without proper dilution. A patch test on a small skin area is advisable before broader application to check for reactions. Topically, clove oil should be diluted with a carrier oil, such as coconut or jojoba oil, typically at a ratio of 10-15 drops per 30 ml.
Ingestion of clove oil is unsafe, especially for children. Even small amounts can lead to severe side effects, including seizures, liver damage, and fluid imbalances. For pets, eugenol can be toxic in large quantities or when undiluted. It can cause symptoms such as excessive drooling, vomiting, respiratory issues, and liver injury in dogs; cats are particularly sensitive due to their inability to metabolize certain compounds. Ensure good ventilation when diffusing clove oil around pets and store all essential oils safely out of their reach.
The effectiveness of cloves as an insect repellent can be less potent or shorter-lived compared to commercial synthetic repellents like DEET. Homemade clove preparations, especially those with low eugenol concentrations, may offer limited protection. Clove oil’s high volatility means it degrades quickly when exposed to air, reducing its sustained repellent action.