Good sanitation is the foundation of any successful fly control program. In most cases, removing fly breeding material is the most feasible means of breaking the fly's life cycle. However, this may be hard to do under some circumstances, and you may have to go to chemical control. Insecticides can be applied to walls, ceilings, and rafters of barns and sheds where flies are resting to help decrease the number of flies. In barns, space sprayers, foggers and misters can be very valuable. You may also use fly control insecticides on the horse. Under severe fly conditions, fly control should be an integral part of the owner's daily horse care activities. Insecticides that seem to work best whether used in spray systems or applied directly on the horse are those that contain pyrethrins. Granular baits are also very good as a supplement to other fly control measures.