Mosquito control is a gnarly problem, no matter which part of the world in which you live. Researchers have evaluated a large number of repellants and insecticides, and it's difficult to find any hard evidence for the efficacy of lemon juice, lemon oil or citric acid as a mosquito deterrent. One animal professional claims that lemons help repel mosquitoes from dogs, though, and lemon oil is sometimes recommended as a folk remedy for mosquitoes. You can't hurt yourself by experimenting, but you may suffer a few mosquito bites in the process.
The Scoop on Lemons
According to entomologist Susan M. Paskewitz, a number of essential oils can be effective mosquito repellants, including peppermint, clove, cinnamon and many others, but lemon oil isn't on her list. Hearing that the combination of citric acid in limes and the fragrance of cloves combine to effectively repel mosquitoes, Natalia de Cuba Romero put the idea to the test. It didn't work; she was driven from her patio by the marauding scavengers. The fact that few researchers even mention lemons in regards to mosquito control is powerful evidence against their efficacy. Nevertheless, animal professional Karen Rosenthal claims that lemons can be used as a topical application and ingested treatment to keep mosquitoes away from dogs.
A Lemon-Based Bug Spray
Rosenthal's recipe for a lemon-based spray for treating dogs may or may not be effective for humans, but it's safe. Squeeze six lemons into a quart of water, bring the solution to a boil, then let it steep for two hours and pour it into a spray bottle. You can spray this liberally on your arms and legs, in your hair and virtually everywhere on your body except in your eyes.
Make Your Own Lemon Oil
Another way to use lemons is to combine them with olive oil and apply the mixture topically to your skin or things you wear, such as belts or bracelets. Rosenthal recommends putting the oil on your pet's collar to repel mosquitoes. To make the oil, peel two lemons, immerse them in 1 cup of olive oil and boil the mixture on low heat for 20 minutes.
Sounds Like Lemons
Lemon oil and lemon eucalyptus oil are two different things, and the idea that lemon oil repels insects may be a simple matter of confusion. Lemon eucalyptus oil comes from the lemon eucalyptus tree (Eucalyptus citriodora), which is hardy in U.S. Department of Agriculture hardiness zones 9 to 11; the U.S. Environmental Protection Agency recommends it as a safe, nontoxic alternative to DEET for repelling mosquitoes. Citronella grass (Cymbopogon nardus) -- hardy in zones 10 to 12 -- and lemongrass (Cymbopogon citratus) -- hardy in zones 10 to 11 -- both contain citronella oil, which can be applied topically or made into candles for area control. Finally, lemon balm (Melissa officinalis) -- hardy in zones 3 to 9 -- contains citronellal, a compound that mimics citronella. Crushing the leaves and rubbing them on your skin is a folk remedy for mosquitoes.