No, but I know salt is good for kiling off slugs so maybe the diluted solution will do the trick with caterpillars. As my garden is totally organic I can't see a little salt doing any harm. It will certainly save me going round daily picking the little horrors off my plants.
Word of warning though I wouldn't spray it on plants in ful sun as it can scorch the leaves.
BTW welcome to A4A Bun nice to have you around here too!!