The term farnesene refers to a set of six closely related chemical compounds which all are sesquiterpenes.

The beta isomer exists as two stereoisomers about the geometry of its central double bond.

Both isomers are also insect semiochemicals; they act as alarm pheromones in termites[2] or food attractants for the apple tree pest, the codling moth.

[3] α-Farnesene is also the chief compound contributing to the scent of gardenia, making up ~65% of the headspace constituents.

[5] Several plants, including potato species, have been shown to synthesize this pheromone as a natural insect repellent.