Shoots pinched at base

This is my first season growing hops, and it's off to a slow start. My rhizome put out one shoot, which grew to about an inch tall, then pinched off at the base. It continued to grow for a little while, but then dried up and died. A new shoot was just coming up at the time, but now it's done the same thing, pinched at the base. I can't see any insects that might be doing it. I've pretty much written this season off as unsuccessful, but I don't want to repeat the same problems next year. Any thoughts? Thanks!

Is it actually pinched or did part of it get eaten? Cutworms chew plants off at ground level and hide about 1/2 cm down in the dirt during the day.

I double checked, and they're actually pinched. A few millimeters above the soil level the stem is just shriveled up for another 1 mm or so. If it might be anything to do with water, I would think I'm probably over watering instead of under watering, which doesn't make sense with the dried out appearance of the shriveled band.

pictures go a long way