when i was a kid (late 50's) me and my buddy would collect the caterpillars for a bate shop along the river. we supplied them about 500 a week as long as the worms lasted, about 11/2 weeks. we laid several sheets on the ground around the tree trunk and then hit it with a sledge hammer and down came the worms. do it a couple times and you had the 500 caterpillars. we got 1 cent each, we lived about 20 miles from the Ohio river and he came to pick them up.