MadSci Network: Botany |
Citronella is an oil from the leaves of citronella grass (Cymbopogon nardus) and C. winterianus. Plants contain thousands of secondary products which are chemicals that often deter animals, including insects, from feeding on them. Therefore, it is logical that citronella oil may be an insect repellant because that is probably its function in the plant. The plant itself has no reason to repel mosquitoes because mosquitoes do not eat plants. Therefore, it appears a lucky coincidence for people that citronella oil repels mosquitoes. It seems doubtful that the plant inself is as good a mosquito repellant as citronella oil in candles or applied to skin or clothing. The reason is that the plant has a waxy surface layer, the cuticle, that prevents the oil from evaporating. Aromatic plants generally have much less aroma than the aromatic chemicals extracted from them. You can try this for yourself with familiar plants such as onions, garlic, catnip, mints, etc. Crush a leaf and the smell is much stronger than from an intact leaf. Therefore, it is unlikely that a garden of citronella grass will protect you from mosquitoes more effectively than citronella oil in a candle or applied to your skin. It might make an interesting experiment. Native to Ceylon, C. nardus can be grown outdoors in south Florida and southern California. Reference About Citronella
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