Watercore of Apples

WHAT IS WATERCORE?

Watercore is a physiological disorder of apple fruit characterized by water-soaked tissue around the vascular bundles or core area due to the spaces between cells becoming filled with fluid instead of air. Affected tissue is water-soaked and glassy looking.

Generally damage is not visible on the skin, and it is only when fruit are cut that the damage is seen. In severe cases flesh can be affected right up to the skin, which then darkens over affected areas.
Some varieties are more susceptible to the disorder than others. These include Braeburn, Sundowner, Fuji, Lady Williams and Red Delicious.

WHAT IS WATERCORE?

Watercore is more of a problem in arid and semi-arid areas. Low night temperatures in autumn and high day temperatures when apples are nearing maturity favour watercore. Low fruit calcium and high levels of nitrogen may increase the chance of watercore in susceptible varieties.

HARVEST

Apples with watercore have high levels of the sugar sorbitol in the intracellular spaces.

In Japan, fruit with radial watercore command a premium price and are known as “honeyed apples”.
They are specially graded and sold quickly.

CONTROL

There are no known cures for affected fruit. Picking fruit before watercore develops and at the correct stage of maturity will help reduce losses. Adequate calcium nutrition and careful use of nitrogen fertilisers can minimise damage in susceptible varieties.