Barrier Parasite Repel Spray. The Barrier Parasite Repel Spray is a 100% natural insect repellent that is ready to use and can rid the animal of all known ectoparasites for up to 24 hours. Parasite Repel can help deter all types of mites, biting and blood sucking lice, midges, ticks and black flies. Barrier Parasite Repel Spray offers a kind and gentle formula that can be applied directly to raw, exposed and broken skin to help soothe and calm the area. The Barrier Repellent offers a horse friendly, quiet, fine action trigger spray than can be adjusted to produce a fine wide mist or a sharp jet spray.