The message
from Noydb contains these words:


That looks (to the untrained eye) like a fungal disease, quite possibley
septoria. If so, give it a shot of a copper or sulfur based fungicide every
8-10 days and destroy (burn or remove from the property) all dead plant
material / deep plow the area in the fall.

Bill
--
Zone 5b (Detroit, MI)
I do not post my address to news groups.

Could be the dreaded potato blight which is what you could be talking
about with septoria.

I hope the potatos are being moved around rather than in the same spot
as thats just fatal for em.