This works! Take it from a paranoid worrywart.
Go buy a healthy supply of Deep Woods Off. I use it on myself and on the head, ears and neck of my horse. I don't like ticks either, nasty little bloodsucking monsters.
Oh, and don't spend so much time worrying or being afraid that you don't enjoy your time with horses.
What am I afraid of? I don't like to fly (but do), I won't take a cruise (I've seen the Posidon Adventure), and Bigfoot. : ) I also don't like trails with a steep drop of to the center of the earth on one side.