Farnam Tri-Tec 14â ¢ Insecticide. Farnam Tri-Tec 14â ¢ Insecticide is a powerful insecticide that can be used to disinfect the horse's environment and kill annoying insects. Farnam Tri-Tec 14â ¢ Insecticide is effective against horseflies, stable flies, house flies, face flies, horn flies, deer flies, mosquitoes, deer ticks, gnats, lice and also the carriers of west nile disease, lyme tick disease, swamp fever and many more. Farnam Tri-Tec 14â ¢ Insecticide contains cypermethrin, pyrethins and strong polymers to ensure it stays in place and effective for up to 14 days. Read more… Do not use on the horse or other animals. Harmful to the environment. Collect from store only. CANNOT be delivered.