Lemongrass repels mosquitoes, ticks, fleas, and several agricultural pests, though its effectiveness varies significantly by insect type and how the oil is applied. The plant’s repellent power comes primarily from citral, a compound that makes up roughly 60 to 70% of lemongrass essential oil and interferes with the way insects detect human and animal hosts.
Mosquitoes
Mosquitoes are the insect most commonly associated with lemongrass, and for good reason. The oil has demonstrated at least 50% bite deterrence against Aedes aegypti, the species responsible for spreading dengue, Zika, and yellow fever. That said, protection from lemongrass-based products is short-lived. A topical formulation containing 1% lemongrass oil provided meaningful repellency for only about 2 to 3 hours in controlled testing.
To put that in perspective, a University of Florida evaluation of commercial herbal repellents found that a product containing 1% lemongrass oil (alongside citronella, peppermint, cedar, and geranium oils) offered just 19 minutes of mosquito protection. DEET-based repellents at standard concentrations typically last 4 to 8 hours. So while lemongrass does repel mosquitoes, you’ll need to reapply it far more frequently than a conventional repellent.
Lemongrass also shows activity against Anopheles funestus, a major malaria-carrying mosquito species in sub-Saharan Africa. Lab studies found that lemongrass oil and its components caused total mortality in mid- to late-stage larvae of this species, suggesting the oil works not just as a repellent but can kill mosquito larvae on contact at sufficient concentrations.
Ticks
Lemongrass essential oil disrupts the ability of blacklegged ticks (Ixodes scapularis, the species that transmits Lyme disease) to detect and respond to butyric acid, one of the key chemical signals ticks use to locate hosts. Research published in Current Research in Insect Science found that both lemongrass oil and its individual components, citral and geraniol, significantly inhibited this host-finding behavior in lab-reared and wild adult female ticks. The effect was comparable to DEET in the same experimental setup.
This is one area where lemongrass performs relatively well compared to synthetic repellents, at least in laboratory conditions. Whether that translates to reliable real-world protection on hiking trails is harder to confirm, since tick encounters depend heavily on vegetation contact and duration of exposure.
Fleas and Ectoparasites
Lemongrass oil appears in several commercial flea products marketed for pets, typically at concentrations between 1.5% and 4.5% and blended with other essential oils like peppermint, thyme, and clove. However, the evidence here comes with an important caution. A retrospective study covering 2006 to 2008 found that plant-derived flea products containing these essential oil mixtures were associated with potentially adverse effects in dogs. The ASPCA lists the lemongrass plant itself as toxic to dogs, cats, and horses, with symptoms including stomach upset in dogs and cats, and difficulty breathing and weakness in horses.
If you’re considering lemongrass as a flea deterrent for your pets, the safety profile is not straightforward. Essential oil concentrations that might repel fleas can also irritate or harm the animal.
Agricultural and Garden Pests
Beyond biting insects, lemongrass essential oil has documented insecticidal activity against the black cutworm, a destructive moth larva that feeds on a wide range of crops and garden plants. The oil’s citral content interferes with a key enzyme in the insect’s nervous system and disrupts a signaling chemical that regulates movement and behavior, ultimately causing paralysis and death. This makes concentrated lemongrass oil a potential tool for organic pest management, not just a repellent but an actual contact insecticide at higher doses.
Growing Plants vs. Using the Oil
A common question is whether simply planting lemongrass in your yard will keep bugs away. The short answer: not very well. A living lemongrass plant releases only trace amounts of volatile compounds into the surrounding air. The repellent effect depends on concentrated oil, which requires the plant’s leaves to be crushed, distilled, or otherwise processed to release meaningful quantities of citral. Standing near a lemongrass plant on your patio won’t create a bug-free zone.
If you want to use the plant itself, crushing a few leaves and rubbing them on exposed skin will release some oil, but the concentration and duration of protection will be far lower than using a prepared essential oil product.
How to Use Lemongrass Oil as a Repellent
Lemongrass essential oil should never be applied undiluted to skin. It’s potent enough to cause irritation or sensitization. For adults, a 2 to 5% dilution works well, which is roughly 10 to 30 drops of essential oil per ounce of carrier oil such as coconut, jojoba, or almond oil. For children or sensitive skin, drop the concentration to 0.5 to 1%.
A simple spray can be made by mixing 10 to 15 drops of lemongrass oil per ounce of witch hazel or distilled water and shaking well before each use. For more targeted application, a roll-on using 5 to 7 drops in a 10ml roller bottle filled with fractionated coconut oil works for wrists, ankles, and behind the ears.
Regardless of the method, plan to reapply every 30 minutes to 2 hours depending on the concentration. The volatile compounds in lemongrass evaporate relatively quickly, especially in heat and wind. This is the fundamental trade-off with plant-based repellents: they’re gentler and carry fewer chemical concerns, but they don’t last.
Regulatory Status
The U.S. Environmental Protection Agency classifies lemongrass oil as a “minimum risk” pesticide, meaning products containing it are exempt from the standard federal registration process required for conventional pesticides. It’s approved for both food and non-food uses. This classification reflects its low toxicity to humans, but it also means lemongrass-based repellent products undergo less rigorous efficacy testing than DEET or picaridin products before reaching store shelves. A “minimum risk” label tells you the ingredient is considered safe, not that the product has been proven to work at the concentration it’s sold in.