Yes, there are bot knives or bot blocks available. Bot blocks are available at any tack shop and TSC should carry them.
Bot knives might be at the tack stores or TSC but I have to order them thru Valley Vet.
Tip for getting the eggs off easier, is to put warm water on them and immediately scrape them off. Warm water tricks the eggs into thinking the horse is licking them, so they loosen themselves from the hair. That's why they don't come off in the cold rain
As a last resort, if I've missed any in a really difficult place, I don't show so I will take a dollar pair of children's scissors and cut the hair off
Bot flies do not land on the horse --- they hover and shoot the eggs thru their tails, onto the horse
There is also a throat bot fly which is different. It will lay eggs deep in the hairs of the throat and jowel area. These eggs have the ability to self migrate into the mouth
. I often have to pull that hair backward to find them.
It's almost impossible to get throat bot eggs off the horse. The best removal method I Have found for throat bots is to smother them in any kind of ointment that isn't harmful to the horse. It can be an antibiotic ointment, hemorrhoid ointment, etc. I use ointments as they are not as messy as creams.
Once the eggs are smothered to death, they can generally be pulled off with your fingernails -----
Where I live, it seems like the bot flies have on and off days where they go looking for a horse. THIS day I might not see any eggs and three days later I may find a spray of several hundred on them --- and not always both horses, not always the same horse -----
The sooner you get the eggs off your horse the better. Whatever that self-sticking "glue" is that attaches the eggs to the hair makes the horse itch, then the horse starts licking and biting, which then removes the eggs into their mouths.
Best time to de-worm for bots is right after the first hard frost. We didn't have a hard frost last year so I de-wormed in mid -December for bots. Whatever paste you buy, be sure the list of worms includes bots