Here's a link that has all kinds of recipes for homemade fly repellant. I've used a few of them myself but I have yet to find anything that works after you have a sweaty horse and go riding in the woods where the deer flys are rampant. I've been chased out of the woods numerous times because those things are relentless and bite the heck out of my horse.
If you don't want to stand behind our soldiers who are in danger zones, please stand in front of one.
If you really open your ears and eyes, you will see that there is alot of great advice given on here. You just have to see it and hear it without closing off your mind.
VanHalen 26 yr QH Stallion R.I.P. 4/11/82 - 5/8/08 24 wonderful years together.
Scout 25-28 yr Paint/Draft Cross Gelding
Glistening 13 yr Arab/Saddlebred Mare