Potato Defect Identification

A number of defects can arise during harvesting and storage of potato tubers. Damaged crops cost the UK potato industry over £200/ha and care needs to be taken at every stage of the production system to minimise this cost.

Planning ahead, routine maintenance and adapting machinery settings to the conditions are key areas to reducing the risk of damaging tubers and preventing avoidable defects.

Symptoms may be present at harvest, some defects can aid disease development and spread through stored tubers and some will only develop significantly during storage. 

The links below provide a guide to the visual symptoms of many common defects. 

At Sutton Bridge Crop Storage Research, a combination of techniques are used to provide a very accurate identification of the cause of tuber defects – contact us for further advice or information.

Our disease and defects poster is also a useful visual summary of what may be affecting your potatoes. Download using the link below.

Download the potato diseases and defects poster

Related content

Potato defects gallery

Browse the images below to identify which defects may be affecting your potatoes. Each defect features a link to further information on the symptoms, causes and controls.


Blackheart is an internal defect caused by low oxygen and high carbon dioxide levels in the tuber. It occurs where the respiration demand for oxygen exceeds the available supply.

This might be due to low oxygen levels in the environment, such as field flooding, or high tuber respiration rates, usually in response to temperature extremes.

Crops are most vulnerable around harvest time where respiration rates are likely to be higher.

a potato with a face drawn on it

Potato bruising and damage

During 2006, we carried out a bruising survey which highlighted the huge effect bruising and damage can have throughout the supply chain.

In a typical business, bruise and damage can cost up to £1,250/ha but averages at £200/ha. So it's very important to try to reduce the risk of damage and bruising.


Exposure of tubers to light, either in the field or during storage, will result in the formation of chloroplasts that contain chlorophyll, the green pigment associated with the irreversible condition called greening

a couple of potatoes

Hollow heart and internal browning

Hollow heart and internal browning are different stages of the same internal defect however they commonly occur separately.

Internal browning is most likely to develop at tuber initiation or when the tubers are small but hollow heart can develop at any tuber growth period.

a piece of food

Internal sprouting

Internal sprouting is a physiological condition where a tuber has a sprout growing either inside it or passing through an adjacent tuber.

Sometimes the sprout may furrow the tuber surface. Usually a combination of factors is necessary for the problem to arise.

a close-up of a seashell

Pit rot

Pit rot is a grouping of defects with similar looking symptoms.

The name refers to the old fashioned straw-covered potato pits or clamps from which the problem was particularly noticeable.

Poor ventilation, high carbon dioxide and low oxygen levels are likely to contribute to the problem.

a close-up of a potato