Cloves are the fragrant flower buds of a tree called Syzygium aromaticum. This species of tree is evergreen, and produces crimson flowers when the buds are allowed to open. Cloves are used mainly in cooking, because they have a strong, aromatic flavor similar to cinnamon, that can compliment a wide range of other foods. They are also used in medicines, fragrances, and other consumer products.
Clove Essential Oil
Harnessing this powerful essential oil.
What are Cloves?
Clove Oil and its Components
Clove oil is rich in a diversity of fragrant compounds. The primary component of clove is eugenol, which can account for up to 90% of the oil content. Among the other components, b-caryophyllene, trans-caryophyllene, and 2-methoxy-4-(2-propenyl)-phenol have been recognized for their insecticidal properties.
The tree that produces cloves evolved to produce these compounds for a very specific purpose. Like many other fragrant, oil-rich plants, this tree uses these oils to defend its fragile buds from insects. By extracting the essential oil of clove, we can harness the power of these natural compounds. The essential oil of clove has been widely studied as an insecticide and antimicrobial agent, and is effective against numerous pests and pathogens.
The components of clove oil are also effective herbicidal agents. Clove oil can control broad-leaved weeds but is especially effective against grassy weeds. When applied properly, clove oil can significantly inhibit the growth of weeds, leading to decreased root and shoot length, chlorophyll content, and cellular respiration.
A photo of dried cloves. Image from Wikimedia.
Pest species which can be treated effectively with clove oil:
- Trichoplusia ni, the cabbage looper
- Sitophilus zeamais, the maize weevil
- Culex pipiens, the common house mosquito
- Bradysia procera
- Acanthoscelides obtectus, the bean weevil
- Haematobia irritans, the horn fly
- Stomoxys calcitrans, the stable fly
- Cosmopolites sordidus, the banana weevil
- Callosobruchus maculatus, the cowpea weevil
- Rhyzopertha dominica, the lesser grain borer
- Sitophilus oryzae, the rice weevil
- Tribolium castaneum, the red flour beetle
Further Reading
Ahuja, N., Batish, D., Singh, H., and Kohli, R. (2014). Herbicidal activity of eugenol towards some grassy and broad-leaved weeds. Journal of Pest Science.
Bakaze, E., Kofler, J., Dzomeku, B., and Wuensche, J. (2020). Natural compounds with potential insecticidal properties against banana weevil Cosmopolites sordidus. American Journal of Sciences and Engineering Research.
Correa, Y., Faroni, L., Haddi, K., Oliveira, E., and Pereira, E. (2015). Locomotory and physiological responses induced by clove and cinnamon essential oils in the maize weevil Sitophilus zeamais. Pesticide Biochemistry and Physiology.
El Gohary, E., Mo’men, S., Hamam, F., and Farag, SH. (2021). Insecticidal, repellency, and histopathological effects of four extracts of clove oil (Syzygium aromaticum) against Culecx pipiens (Diptera: Culicidae). Egyptian Journal of Aquatic Biology & Fisheries.
Hong, T., Perumalsamy, H., Jang, J., Na, E., and Ahn, Y. (2018). Ovicidal and larvicidal activity and possible mode of action of phenylpropanoids and ketone identified in Syzygium aromaticum bud against Bradysia procera. Pesticide Biochemistry and Physiology.
Jairoce, C., Teixeira, C., Nunes, C., Nunes, A., Pereira, C., and Garcia, F. (2016). Insecticide activity of clove essential oil on bean weevil and maize weevil. Revista Brasileira de Engenharia Agrícola e Ambiental.
Jumbo, L., Haddi, K., Faroni, L., Heleno, F., Pinto, F., and Oliveira, E. (2018). Toxicity to, oviposition and population growth impairments of Callosobruchus maculatus exposed to clove and cinnamon essential oils. PLoS ONE.
Mittal, M., Gupta, N., Parashar, P., Mehra, V., and Khatri, M. (2014). Phytochemical evaluation and pharmacological activity of Syzygium aromaticum: A comprehensive review. International Journal of Pharmacy and Pharmaceutical Sciences.
Showler, A. T. (2017). Botanically based repellent and insecticidal effects against horn flies and stable flies (Diptera: Muscidae). Journal of Integrated Pest Management.
Zeng, L., Lao, C., Cen, Y., and Liang, G. (2010). Study on the insecticidal activity compounds of the essential oil from Syzygium aromaticum against stored grain pests. 10th International Working Conference on Stored Product Protection.
