After blooming, lower leaves wilt. When cut a creamy yellow to light brown rot shows just beneath the skin. Later the skin of the potato cracks and the center breaks down, leaving a thin outer shell. Plant only certified seed potatoes. Dispose of infected plants in the garbage.
Tubers are small, irregularly shaped, knobby and show a black scurf.
This fungus attacks plant stems below the ground and interferes with movement of food down to the tubers. Plant in newly turned soil. Plant when soil is warm and plant shallow and hill gradually as the shoots grow. Cut off green parts as these are poisonous to people and lifestock. Keep tubers well covered with soil and move harvested potatoes into dark storage within 1 day of digging.