North Shore Greenhead Fly Program

Greenhead program - in streamIn the early sixties, public demand for relief from the nuisance of greenhead flies resulted in the organization of the North Shore Greenhead Fly Program. The project developed an environmentally friendly method of controlling greenheads. Several years of research led to the development of the greenhead fly trap. The project became routine operation of annual deployment, retrieval and maintenance of traps. The operation continues today with the exceptions of the development of Octenol  as an attractant which is now used in the traps.

The Greenhead fly (Tabanus nigrovittatus) is a species of biting horse fly commonly found around coastal salt marshes of the Eastern United States. The biting females are seen as an excessive pest to humans and animals, seeking out a blood meal in daylight hours, attacking persistently. These flies have a short life span, appearing in early July, and extending through August. Greenheads are not life threatening but they are a huge nuisance and threat to tourism. They are fairly resistant to pesticides; in return the district sets almost 400 traps out in six towns in June, along the creeks of the salt marsh, to prepare for the invasion of the Greenhead fly. These traps are 4 foot tall black boxes with legs, giving a silhouette appearance of a grazing animal. This entices the flies to bite the underbelly of the trap, which has a small opening for the flies to go into and get stuck inside the box. Single traps can capture hundreds of flies per day, preventing further reproduction, creating a huge reduction in greenhead overall annoyance. The trap is simple, yet highly effective. Traps are set by walking out to the marsh or by boat along the creeks. Location of the traps are key, trap location is subject to change based on the district’s research and historical data for said salt marsh.









Octenol is short for 1-Octen-3-ol and also known as mushroom alcohol or ox breath. It is a chemical that attracts biting insects such as mosquitoes and greenhead flies. It is contained in ox breath, human breath and sweat. Octenol is used, sometimes in combination with carbon dioxide, to attract insects in order to kill them with certain electronic devices. Its odor has been described as moldy, meaty or vaguely similar to anise or licorice.