Flight school for crop duster pilots can require up to 30 hours of practice. But first you have to get arial instrument certified which requires a week or so of testing. After that you can start out in small planes and take a couple laps and just learn basics. After so many hours at that plane you move up to next level which you than learn more about crop dusting soon you'll get to fly with an instructor and dust a field yourself. After 30 hours of practice you get your ag pilot license and can go out on your own and start your career as a pilot. Then after this if you choose you can move up to the next level all the way up to commercial.