Symptoms and Control Methods of Potato Black Heart

[Disease Diagnosis]

Mainly the tuber storage organ is affected. In the central part of the tuber, irregular patterns of black to blue-black form, developing from a spot to a patch into black heart. As it develops severely, the entire tuber can become discolored. The affected black heart area has a clearly defined edge. In the later stage, the black heart tissue gradually hardens. At room temperature, the black heart area can soften and turn ink-black. Different tubers vary greatly in their reaction to black heart.

[Cause]

This is a physiological disease caused by insufficient oxygen supply to the internal tissues of the tuber, resulting in respiratory suffocation. Under different environmental conditions, the changes from internal pinkish-brown discoloration to necrosis, up to the black heart formed by severe development, are all caused by oxygen deficiency. When oxygen is excluded from or cannot reach the internal tissues of the tuber, black heart gradually develops. At the same time, the development of black heart is affected by temperature. At lower temperatures, black heart develops more slowly; but at excessively low temperatures (0-2.5°C), black heart develops more rapidly; and at extremely high temperatures (36-40°C), even with oxygen present, black heart still develops because oxygen cannot diffuse rapidly through the tissues. Therefore, excessively high or excessively low extreme temperatures and excessively sealed storage conditions (poor permeability) all aggravate the black heart condition.