What stand population do you have left? Two things in your favor- the slug looks pretty big so may be near done eating. Also they do the most damage to cotyledon stage beans. But that one looks extra ambitious.

I had over half a field eaten by them in late May. Replanted and a little but not much feeding on the replant. I guess their life cycle was about over. Makes you sick when you see half your beans mowed off.

edit to add: We no-tilled into existing stand. It was very spotty damage, either good stand or decimated. Planted at an angle and changed the population on the go, from a half rate to a full rate depending of course on the existing stand. Worked good.