Durvet Permethrin-10 Long-Lasting Fly Repellent with up to 28 days of residual activity for just pennies a horse! This long-lasting fly spray features a new, exclusive, safer formula. (Residual activity for up to 28 days*) Our best results came from mixing from 2 to 4 ounces of concentrate in a gallon of water and for some extreme infestations up to 6 ounces per gallon for spot treatments on the ears, face, and along the backline. ( Mfg suggests starting at 2 ounces per gallon and increasing the amount if needed in heavy infestations.) Durvet Permethrin-10 virtually no odor when mixed with water. Effective against one of the widest range of insects available. Among the many pests this fly spray is effective against are: horn flies, face flies, lice, ticks, deer ticks, mosquitoes, and many other pesky insects.
