Most flies emerge sometime from May through August. Some species of horse flies have two generations per year in coastal Georgia. Most species of horse flies and deer flies have a 1-year life cycle. In other cases, a full generation and a partial second are produced within a single year. Chemical control of horse flies and deer flies is difficult.
Some repellents give temporary relief.
Large-scale pesticide applications to control adult horse flies and deer flies have only been moderately successful. Treatment of salt marshes to control larvae is impractical because of the large areas which larvae inhabit. Vegetation should be kept low around the trap.