Are these bots located in certain parts of the country or can they be found anywhere?
As far as the regular bot flies, I have found them on my horses from PA to SoCal and now in Tennessee. I grew up in NE Ohio and was picking bot eggs off my horses back in the 60's, so they've been around forever.
I don't know about the throat bots. The .edu website I posted is from Hawaii. I now live in Middle Tennessee and I never saw them until I moved here.
Putting warm water on bot eggs will trick them into thinking the horse is licking them, so their a bit easier to get off until the water cools down.
Someone on one of the forums said they rubbed their horses' legs with mineral oil and that kept the bots from laying eggs but the legs gathered layers of dirt every day that needed cleaned off.
Fly spray generally doesn't work because bot flies don't land on the horse. They literally shoot the eggs out of their tailshaft onto the horse - yuk.
For me, it seems like every other day the horses come in loaded with eggs and the temps can be the close to the same on both days. I don't get that, but it seems to be pretty much the routine.
It's a lot of work no matter what we try