When cows head to the barn for water on Dick Thompson's farm, they pass through this fly control structure. Insecticide wicks and screen traps help control the flies . Cows walking from the barns to pasture pass through the fly trap, which has folded screens in the sides and several plastic jars holding insecticide wicks in the center, suspended by rope from the top of the structure. Flies enter through holes punched in the bottom or base of the Z fold.
Flies fly up and also toward the light, which comes from the outside.
The flies don't go back through the hole. Thompson cleans out the flies by opening a hinged door at the bottom of each of the six boxes. Overall, the structure is 36 inches wide and 68 inches tall where the cows pass through, and about 11 feet long. Each of the side boxes is made of 1x8-inch boards. The box is 36-inches wide and 60 inches tall.