Control Project Activities

What are we doing to control Greenhead Flies on Cape Cod?

In order to control the number of greenhead flies, the Cape Cod Greenhead Fly Control District (CCGCD) has been using blue box traps.  

Traps only attract females that are searching for a bloodmeal. The box trap has been used by the CCGCD for over 40 years. This box acted as a visual attractant. Over 800 traps are deployed in Barnstable County each year.

Where are the traps placed?

All box traps are placed on the salt marsh. Traps are not as effective when placed in yards because the majority of flies complete their lifecycle on or around the salt marsh. Further, the traps are not competing with any structures for the fly’s attraction when the traps are placed on the marsh.

Why are the traps painted blue?

All traps are painted blue because the color blue has been proven to be the most attractive color to blood-seeking greenhead flies.

Have you heard about artificial ox-breath?

The Cape Cod Greenhead Fly Control District, with funding through the Kelley Foundation, a study in 1992 to determine the effectiveness of adding a scent bait to the traps. Previous studies demonstrated that tsetse flies and mosquitoes were attracted to octenol, popularly known as artificial ox-breath. We found that by adding octenol to our traps we could attract up to three times as many flies as we were with the empty traps. Half of the traps are baited with octenol each year.

How many flies are caught in a box trap?

Anywhere up to 30,000 flies are found in each trap at the end of the summer.