those budworms

where do they come from moths ?
i thought. but i dont have much moths but lotsa bud worms
where do i start at killing em i use bt in the beggining stages but this been goin on for months and i cant get rid of em thinkin maybe theyre in the soil or something ?

ok i found some good info on their lifecycle n stuff from below but can i use bt on the soil every 2 or 3 days maybe or will it not mix with my ferts? anybody tried