Where does citronella oil come from?

Citronella oil is derived from the drying of a grassy plant called Cymbopogon Nardus. It is a natural product as opposed to a chemical repellent such as is used in a bug spray repellent.According to the EPA, citronella oil has been used for over 50 years as an insect repellent. It works to repel insects without harming or killing them. Citronella oil repels varies insects such as mosquitoes, black flies, flies and ticks.It has a distinctive odor which makes it difficult for some insects to locate a host.