Question
I had a fully grown row of scarlet runner beans. Then whole stems stated dying. I found that the stems had been severed anywhere from 12 in. above ground to about 36in. What could be doing this.

Thanks Peter

Answer
Some kind of chewing insect - you could try BT, an organic worm and caterpillar biologic control, or at dusk you could use Rotonone (a powder) which is an all purpose organic insect killer...but wash it off early in the morning because it will also kill bees and other beneficial insects.