Current weather and delay conditions for (GRU) Sao Paulo-Guarulhos International Airport Conditions
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.
Chapter Five: DEET. N,N-Diethyl-m-toluamide, also known as DEET or m-DET, is an aromatic amide that is an effective insect repellent for control of biting flies, biting midges, black flies, chiggers, deer flies, fleas, gnats, horse flies, mosquitoes, no-see-ums, sand flies, small flying insects, stable flies, and ticks.