Hi there, I think it's because it's a species that could survive here and thus become a threat to our tomato industry as its their food plant. Pity as they look so yummy, I would like to try and raise another similar species, like hawkmoth larvae or something, I think I'll stick to silkworms. Tom at the silkworm store is very helpful if you need to ask anything , my first lot I bought was the colony, you get young silkworms, a container and enough ready made chow to feed them through, it was a good way to dip your toe into finding out whether you want to keep them again,
Good luck.