Citronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon (lemongrass). The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol, and geraniol. These chemicals find extensive use in soap, candles and incense, perfumery, cosmetic, and flavouring industries throughout the world. Citronella oil is also a plant-based insect repellent and has been registered for this use in the United States since 1948. The United States Environmental Protection Agency considers oil of citronella as a biopesticide with a non-toxic mode of action.
Research also shows that citronella oil has strong antifungal properties, is effective in calming barking dogs, and has even been used as a successful spray-on deterrent against pets destroying household items.
Citronella oil is classified in trade into two chemotypes:
Both types probably originated from Mana Grass of Sri Lanka, which according to Finnemore (1962) occurs today in two wild forms--Cymbopogon nardus var. linnae (typicus) and C. nardus var. confertiflorus. Neither wild form is known to be used for distillation to any appreciable extent.
Citronella oil from Cymbopogon species should not be confused with other similar lemony oils from Corymbia citriodora and Pelargonium citrosum.
Direct application of citronella oil has been found to raise the heart rate of some people.Health Canada banned the oil's use as an insect repellent in 2012 but later lifted the ban in February 2015.
At present, the world annual production of citronella oil is approximately 4,000 tonnes. The main producers are China and Indonesia - producing 40 percent of the world's supply. The oil is also produced in Taiwan, Guatemala, Honduras, Brazil, Sri Lanka, India, Argentina, Ecuador, Jamaica, Madagascar, Mexico, and South Africa.