Stan LOVES Katydids... unfortunately they are friggin imPOSSIBLE to catch.... Honestly from all that I have looked through the rule of thumb I found was that bright is bad.... And I may be wrong but I don't know of any tobacco areas around Granbury so I think your good I have asked around with different herp owners in the Dallas area and have found that most of the hoppers in our area have been fed off with no problem... The only time I've ever heard it was bad was when they did all the west nile sprays in our area but that was where I lived I can't speak for Granbury... I WOULD love to get a colony of these guys going though my chams love hoppers
To make your research less of the burden. The only grasshoppers in North America that are poisonous to my knowledge are lubbers (the brightly colored hoppers).