Things You'll Need
- Plastic soft drink bottles
- Raisins
- Wood chips
- Water
- Roll of string
- Scissors
Instructions
Remove the caps from the bottles.
Add approximately 1/8 cup raisins to each bottle for each 16-oz of capacity. For example, add 1/8 cup raisins to a 16-oz bottle, 1/4 cup raisins to a 1-liter bottle and 1/2 cup raisins to a 2-liter bottle.
Add about six wood chips to each bottle to provide the flies a place to land when they enter the trap.
Cover the bottom of each bottle with approximately 3 inches of water. Do not add more water or it will dilute the sugar content of the raisins.
Set up the traps. If possible, place one trap at the base of each fencepost around the pasture on the outside of the fence. If you do not have enough bottles to accommodate every fencepost, select posts in the areas where you have seen the largest concentration of flies or space the bottles out evenly around the pasture.
Tie the necks of the bottles to the fencepost with the string. This will keep the bottles from falling down or being knocked over by horses.
Check the bottles frequently. As the raisins begin to break down, they will begin to ferment. This will both aid in attracting flies to the bottles and will make the flies intoxicated as they consume the fermented solution, causing them to fall into the solution and drown.
Empty the traps when you see that more than half of the surface of water is covered with flies.