Horseflies are painful pests that feed on the blood of all mammals, including humans. The flies trace and find their prey by targeting the prey's appearance, movement and smell. Most fly control methods target the horsefly's olfactory senses. Plant-derived essential oils are known to repel horseflies because of their strong odor.


Citronella oil is a natural insect repellent obtained from lemon grass; it is an ingredient in repellent sprays, both homemade and commercial. While making your homemade fly repellent, beware of the petroleum-based citronella oil product to which citronella scent is added and marketed. Use 100 percent pure plant-derived citronella natural essential oil to avoid skin-sensitivity issues.

Natural Repellents

Essential oils made from eucalyptus, peppermint, lavender, tea tree and pine needles also keep the bloodsuckers at bay. Commercially available fly repellent sprays and lotions come as oil-based and water-based natural herbal extracts and essential oils. Chemical repellents scented with citronella and enriched with other botanical ingredients like lanolin and aloe are also marketed for application to animal skin. You can make natural insect repellents by using water; an emulsifier; and essential oils like citronella, eucalyptus, cedar wood, geranium or cinnamon oils, which have a strong natural smell that masks the mammal's smell and thus keep horseflies away.

Garlic and Apple Cider Oil

Garlic is an organic horsefly repellent. You can make garlic into a solution that you can spray by mixing the garlic with water in a 1-to-5 ratio. After consulting with a vet, you can add garlic to horse food in powdered or freshly ground form; although this process takes time to produce the desired effect, the garlic-scented horse secretes are known to deter horseflies. Another option is to mix small amounts of apple cider vinegar with the animal’s drinking water; consuming this solution is known to change the blood pH of the horse, thus keeping horseflies away. Cider vinegar, coupled with essential oils, is also used in home sprays as the sharp odor may repeal horseflies.

Herbs That Repel

Companion planting with herbs is an insect-control technique in which you grow herbs along with other vegetables in your garden to repel destructive insects and attract beneficial insects. Companion herbs benefit your garden plants and serve your pest-control needs. You can grow herbs like basil, spearmint, bay, lemon balm, catnip, lavender and tansy in pots; these strong smelling herbs work magic on keeping horseflies away from your garden and house. You can enjoy your stroll in the garden in hot, muggy weather without worrying about horseflies if you rub fresh herbs on your exposed skin or spray an extract of leaves from the herbs to have a fly-free zone.