Funny that...
I tipped out a pot with a failed tom plant still in, and there were several small white grubs wriggling around. They were no much bigger than a grain of rice, but easily discernible, and squashable of course!
The tom had been nibbled around the roots, but no other toms had the problem, thank goodness!
I'm trying tom cuttings for the first time this year, (a chum is away for a long holiday, so I'm nurturing some plants for when they get back), and there are about fifteen, so I hope they work, but it's amazing how easy it is!