This is a fiber string, installed to give the Pickeling cucumber's something to climb on.
Very interesting how we decided to use fiber,( we were told to by an experienced Gardener, We asked for advice, he most graciously gave freely of his advice. ) We decided to use wire. The Gardener said Why did you ask then? Now you know the rest of the story. Fiber it is then!!!! By Gollies !!!!.