No-see-ums, also known as biting midges or sandflies, are tiny blood-sucking insects that are difficult to see, hence their common name. Measuring only about 1/16th to 1/8th of an inch, these pests can easily slip through standard window screens, delivering a bite that results in an itchy, red welt. Female no-see-ums require a protein-rich blood meal to produce eggs, and they locate hosts by sensing exhaled carbon dioxide, body heat, and sweat. Effectively repelling these persistent biters naturally involves a two-pronged approach: using plant-based topical deterrents and modifying the surrounding environment to make it less hospitable.
Essential Oils and Plant-Based Repellents
Natural repellents utilize plant compounds that interfere with the insects’ highly developed sense of smell.
Oil of lemon eucalyptus, derived from the leaves of the lemon-scented gum, is a potent natural option. Its active component is para-menthane-3,8-diol (PMD). The strong, aromatic scent of this oil has been shown to rival some synthetic repellents in deterring a broad range of insects.
Citronella oil is another well-known repellent, traditionally used in candles and sprays, which contains the compound citronellal. This oil’s powerful citrus-like aroma creates a repellent barrier that midges and other insects find highly unpleasant.
Other essential oils also provide significant repelling effects against biting midges, including lavender, peppermint, and cedarwood. Lavender oil, which contains linalool, has been shown to be effective, while peppermint and cedarwood oils are known to have strong scents that act as direct deterrents. These botanical extracts work because they contain compounds that are naturally designed to protect the plants from insect predation.
Modifying the Environment to Deter No-See-Ums
Eliminating the conditions and habitat where no-see-ums breed is the most effective long-term strategy. They are strongly attracted to moist, humid environments and typically lay eggs in damp soil, muddy areas, or decaying vegetation. Eliminating standing water, improving yard drainage, and removing leaf litter and overgrown shrubs reduce breeding sites.
No-see-ums are notoriously weak fliers, making simple airflow a highly effective deterrent. Installing outdoor fans near seating areas or using ceiling fans on porches creates a strong breeze that prevents the midges from landing and biting. This method is particularly useful during peak activity times, typically dusk and dawn.
For effective physical exclusion, install fine-mesh screening, often referred to as no-see-um mesh. Additionally, reducing bright outdoor lighting or using warmer, indirect lights can help, as the females are sometimes attracted to light sources.
Proper Application and Safety Precautions
Essential oils are highly concentrated and must always be diluted before being applied directly to the skin. For a topical repellent, a dilution rate of 5% to 10% is generally recommended for adults. This means mixing approximately 30 to 60 drops of essential oil per ounce of a carrier oil. Suitable carrier oils include lightweight options like jojoba, coconut, or almond oil, which help spread the active ingredients evenly and adhere them to the skin.
Before applying a new repellent mixture liberally, performing a patch test on a small area of skin is essential to check for any adverse reactions. Natural compounds evaporate quickly, offering a shorter duration of protection than synthetic alternatives. Users should plan to reapply natural repellents every one to two hours, especially during periods of high midge activity or when sweating.
For sensitive populations, such as young children or pregnant individuals, a lighter dilution of 1% to 2% is often advised. Alternatively, the repellent can be applied only to clothing instead of the skin. While essential oils are natural, they can still be potent, so caution must be taken to avoid contact with the eyes and mouth during application.