Tuber Internal Growth Defects: Blackheart

Blackheart can develop around harvest, in storage and in transit as inside trucks. It is caused by an oxygen deficit at the center of the tuber. Oxygen deprivation results in asphyxiation, loss of respiration, and death of cells.

External Appearance:

Blackheart in potatoesIt can not be detected externally.

Diagnostic Method:

Cut longitudinally.

Internal Appearance:

Blackheart appears as an internal browning to blacking of center tissue. Usually, there is no cavity. Pattern is irregular but margins are well defined. Affected tissue is firm, not soft as with leak, but, when temperature is greater than 65oF, it may turn soft and inky. There is no odor as with leak.


Any pre-harvest, storage and transit condition that prevents oxygen from reaching the tuber center will result in blackheart. These conditions are commonly poor ventilation, water-logging, long exposure to high field temperatures (>90oF) before harvest, and prolonged storage at low temperatures (<35oF). Tubers used as seed can have lower vigor and stand since tuber starch reduced in bulk and may not support emergence.

Cooking Appearance:

Boiled or baked tubers will be black in the center. Chips usually have a black center or a hole. Fries will be black in the middle or be split in two.

Control Measures:

  1. Good ventilation in storage prevents blackheart.
  2. Avoid poorly drained ground. Avoid flooded areas.
  3. Avoid closed bins, deep piles and poor ventilation.
  4. Avoid poorly aerated trucks and storage.
  5. Avoid temperature extremes, inhibit diffusion of oxygen through tuber.