Potato blackleg

Hi everyone, i'm new to growining veg and have come here for some very welcome advise. I grew a mixture of veg last year in a small raised bed and was very happy with the results so i got a bit more brave this year. My wonderful partner who isn't at all intrested in growing anything, made me two raised beds side by side with a path down the middle for easy weeding. In one bed i have carrots,beetroot, cabbage,cauliflower, broccoli, brussels, onions and lots of salad leaves. This bed looks fantastic and it's thrieving. I can't say the same about the other bed. I kept this bed for potatoes only. Everything went well, i chitted them, they were fine, i planted them, they were fine, they came through, they were fine, i built them up, they were fine, then it has all gone wrong. I noticed after heapping them up one plant didn't come through. At first i just thought bad luck i still have 19 plants it'll be fine. But then a few days later one of the plants that had come through started to wilt. Then yesterday i noticed another one wilting. I was horified. I've looked on the internet and worked out they have blackleg, i've dug out the tree plants that have been effected but i don't know what to do now. I'm worried in case it spreads to the others. Reading about blackleg it seems as if the tubers are the problem not the soil. I'm devistated, can anyone out there give me some hope for my remaining plants and some advise about what to do next.
Sorry to go on a bit but its like a member of my family getting more and more sick but i can't do anything to help.