Essential oils are produced in the oil glands of plants. They're extracted for human use by steam or water distillation or through the use of solvents. Essential oils are most often used in aromatherapy to improve health and well being. But some essential oils are also effective insect repellents. Essential oils are an alternative to chemical insect repellents. Wear the oil dabbed on the skin and sprayed lightly on hair or clothing to repel insects. Dilute essential oils in a neutral oil such as almond or olive oil before applying to skin.
The essential oil of lemon grass contains citronella, which has long been a popular mosquito repellent, most often used in outdoor candles.
Essential oil from lavender repels insects, hence lavender's popularity as a moth repellent in clothing chests and linen closets.
Tea Tree Oil
Tea tree oil, from the Australian tea tree, is also effective at repelling insects, according to Colorado State University's Cooperative Extension Service.
Oil of pennyroyal is an effective repellent for fleas, ticks and mosquitoes. The Cooperative Extension Service of Colorado State University cautions that oil of pennyroyal is very toxic and should be used with caution by a certified herbalist.
The fruit of the Osage orange tree, also know as hedge apples of bowd'ark, contains an essential oil that researchers at Iowa State University have demonstrated repels German cockroaches, the brown cockroach found in many areas of the country. The oil can be applied as a barrier to keep cockroaches out of the home.