Well, what are the rules here? Wasp the size of a horse obviosuly couldn't fly as fast.
I'd use a flame thrower. Because I'm sure it doesn't need any advanced skill, just pull the trigger and burn that mofo!
I would use my bare hand and bite to kill this bug. Trust me, I have kill countless bugs because I hate them or they in my way or my place. Flies fear me. The horse-size wasp will flee from me. Like Blackbeard flee from Akainu.