Q.Raising Sweet Potato Plants
After putting potatoes under sand and sawdust, our potatoes are rotting in the ground in just a few weeks. We have been raising and selling plants for over 40 years and have not had any problems until the last 4 years. We switched from Centenials to Bolegards a few years back and wondered if that had made the difference, or do we need of a fungicide?

Certified GKH Gardening Expert
It does sound like it is a fungus or disease, but which would be hard to tell which without knowing more about the symptoms. This article lists some possible diseases it could be and how to correct them:
http://www.clemson.edu/extension/hgic/pests/plant_pests/veg_fruit/hgic2214.html

The patatoes are looking like they had been baked and left out to rot. It seems that the whole patatoe rots at once. You hit the skin and punch through and its all rotten. They rot almost in 2 to 3 weeks. We do use horse manure, but we have used it too for many many years