The horsefly is a bloodsucking insect with a painful bite. While there are many commercial horsefly repellents available, most of them contain DEET, which can cause an allergic reaction. Fortunately, there are several home remedies that are reputed to repel horseflies.
Essential Oils
The essential oils of eucalyptus, tea tree, lavender and sandalwood can be used to create a natural horsefly repellent. These oils can be mixed with water in a spray bottle and sprayed on as needed.
Garlic
Garlic is credited with being the most powerful natural horsefly repellent there is. Crushed garlic can be mixed with water and sprayed on in the manner of essential oils, but this smells rather unpleasant. Eating the garlic works as well, by causing your body to secret compounds that repel flies.
Elder
The leaves of the elder bush, Sambucus nigra, have an unpleasant odour when bruised. Carrying a flowering twig of this plant, or rubbing bruised leaves on one's skin, will prevent flies from settling on a person. An infusion can also be prepared by seeping the leaves and twigs in hot water overnight, then straining it and using the liquid in a spray bottle.