That would take a lot of resources though. We'd have to be able to like successfully gather enough laborers to do that work. Although i guess if the world was in a giant bug crisis most people would be willing in the first place.
I actually have no idea. I wouldn't know if size has anything to do with immunity to chemicals. It would depends on the situation. Or i have a better idea, just get a GIANT shoe. I don't think it can build immunity against that~