I bought hornworms once for my bearded dragon and I believe I got them from Mulberry Farms, and if so they have hornworm chow that they sell, but I think I remember looking up how to raise them and some website list possible trees, leaves, etc you can feed them on.
Here is a list of a recipe for solid food but I don't know how viable it is for moths, just says for the worms:
http://www.entm.purdue.edu/Entomolog...nduca.diet.htm
or even check out this website:
http://insected.arizona.edu/manduca/manual.html