I tried to find any info on silkworms being used for discus food but couldn't find anything except Hikari Discus Bio-Gold uses silk worm pupa in its ingredients.
To be honest, I think you would save alot of money if you try your own food preparation skills and make a mix of your own. There are alot of recipes in this section. Making your own mix, gives you the comfort of knowing exactly whats going into your fish and you get to watch how they develop from something you made.
Sorry I couldn't be of much more help.
Eddie