Homemade Fly Repellents for the Yard | eHow
Flies naturally dislike the taste of soap, and simple dishwashing soap can be quite a powerful bug repellent. To make your own fly repellent, simply mix a few teaspoons of your favorite liquid dishwashing soap into a gallon of water. Use that pre-mixed concoction to fill a spray bottle each time you go out to your garden or lawn.