Hi Spiffy......
Your right, I was assuming that hornworms would have the same switching issues as silkworms, as well as saturniid Moths (I raised Larva on a walnut leaf powder based Bug Burger) , and Phasmids (I have been playing around for a few years now with Phasmid gel diets using Bramble and Euacalyptus leaf powder based formulas (different formulas) I just assumed that hornworms would be difficult to switch also, so wanted to make sure people considered the possibility.
As far as bug burger being a complete diet, I spent a lot of time developing and researching the formula and ingredients (It contains over 50 ingredients), and it should meet the nutritional requirements of most all non host specific grain/leaf eating insects quite well. One of our customers has been using it exclusively for more than a year with hornworms, so I would assume that this would be more than just a few generations.
The only concern expressed was that when mixed at 3:1 the worms were producing excessively runny poops, and this was resolved by reducing the ratio to about 2.5:1.
Cheers, Allen