There are more than 100 varieties of horse flies in the state of Texas alone. According to the Texas A&M website, they are not only pesky because they are flies, but they are also capable of inflicting a painful bite on human and animal skin. This can cause the bitten area to swell and remain painful for days. One of the reasons horse flies are attracted to water is because they lay eggs near water sources. Since the females are the biters, it is especially important to keep them away from swimming pools.
Horse Fly Prevention Methods
Remove any trash or food sources from a swimming pool area. Flies are drawn to garbage for food, so cover any trash cans and keep them as far away from the pool as possible.
Purchase a commercial fly light trap at a garden or home improvement store. This will attract the flies to the light, and then destroy them when they touch the device.
Hang sticky fly strips around the pool's area, high enough so that that people won't walk into them. Change them often.
Homemade Fly Trap
Mix 2 cups of water, ½-cup of sugar and ½-cup of vinegar together to make fly bait, according to instructions found on Show Horse Promotions website.
Cut an empty soda bottle in half and turn the top upside down. Place in the base of the soda bottle.
Pour a few tablespoons of fly bait into the trap.
Punch four holes on the sides of the trap with an ice pick and loop string on the holes so that the trap can hang from a wall or fence.
Hang several traps around the pool area and discard them when they are full of dead flies.