After several years of refinement in trap design as well as the study of optimal trap location, we are confident that such traps will capture flies in numbers great enough to decrease the salt marsh greenhead problem in local areas. What we don't know is whether or not the continual removal of large numbers of these flies over several seasons will reduce the size of the total fly population. To put the results of these studies to good use, we are encouraging all interested coastal dwellers to build and maintain one or more of these simple trapping devices. Essentially the trap is a four-sided box having a screen top and open bottom. This box stands on legs so that its bottom is about 2 feet above the marsh surface.
Flies enter the trap from below and move into secondary traps on the top of the box.
The design is simple. The sides of the box can be made of a number of materials including plywood, cardboard, or plastic sheeting tacked to wooden framing. Build a box 15 x 32 inches on a side fastened to corner posts. Also nail a strip to the top of each side for later attachment of the screen top. The bottom of the box remains open.