Q.What Has Caused Dark Lines On Skin And Inside Of Potato.
Grown five bags of potatoes. Few potatoes in one bag affected others OK. Don’t know if compost can be put back onto vegetable plot without causing further problems.
Certified GKH Gardening Expert
Uh oh. That's a bad one. Looks to be potato pink rot. Treatment with fungicides will, almost always, lead to the disease developing a resistance and becoming much worse.
Here is an article that will help: