Uhggggh! I hate spiders (major shivers). I usually combat them with a combination of a broom, my dad's Shop-Vac, and some creative "singing" and "dance steps."
Sometimes it's a losing battle, the webs are back the next morning. Shoot, I just vaccumed my own room yesterday afternoon, and by evening, there was a giant daddy-long-legs-type bugger hanging in the corner that I'd just swept.
I've heard the plug-in repellers for mice also work some on spiders, but I don't know if they bother horses, I've never tried them.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown