Problem With Running Butter Beans
What is the cause of silver steaking on running butter beans and some streaking in the hull of beans? After streaking is on leaves, plants do not produce.
It sounds like a virus of some type. You might consider taking samples to your local agricultural extension office for testing and recommendations. In the meantime, this article might help: http://www.clemson.edu/extension/hgic/pests/plant_pests/veg_fruit/hgic2200.html