Beginner Gardening: potato problems, 2 by qterhrs

qterhrs wrote:
This is the first time I've tried growing potatoes and they started great but now they look like they have some kind of disease. Planted Yukon Gold & Red Norland in grow bags with a mix of garden soil, shredded leaves, coir and container potting mix. Having a bigger problem with the red potatoes but they are both affected. Does anyone know what this is and how to prevent it for future plantings. Thanks.