Perhaps the most exciting development in natural mosquito repellents involves nepetalactone isomers found in catnip (Nepeta cataria) and catmint (Nepeta parnassica) essential oils. Nepetalactone has been shown to interact with antennae of Aedes aegypti, and may represent a biologically active compound (12). Catmint essential oil was tested for landing and biting rates for Aedes cretinus and Culex pipiens, and then compared to the rates for DEET repellency. When formulated at 20% in ethanol and applied dermally, catmint essential oil was an effective repellent against Aedes cretinus for ~3hrs, and against Culex pipiens for ~2hrs (13). The single isomer Z,E-nepetalactone was also effective against mosquitoes when diluted at 10% in ethanol and applied to skin (13). Compared to DEET, catnip essential oil was found to be a better spatial repellent against Aedes aegypti, Anopheles albimanus, and Anopheles quadrimaculatus, and almost as good a contact repellent (12).
The protection period reached up to 8hrs, with complete repellency (landing and biting) (2). One of the most effective tested formulations included catnip essential oil at 2% and may chang essential oil at 2% by volume. These dilutions were not an irritant to the skin, and pose a safe and effective basis for a natural mosquito repellent (2), however, Tisserand and Young (9) suggest a maximum concentration of 0.8% for may chang essential oil.
Based on these data, I suggest using a repellent containing catnip and may chang essential oils, emulsified in an aqueous solution. Both catnip and may chang essential oils are safe for topical use in adults, pregnant women, and children (9), and are pleasant smelling.
READ MORE ABOUT MOSQUITO REPELLENTS MADE FROM ESSENTIAL OILS AT AROMACULTURE MAGAZINE-May 2017 issue