Bitter pit

Bitter pit (also bitter pit to Middle Low German stip ( p) e = point ) is a deficiency in apples.

Damage

On the shell small, sunken, usually only pinhead-sized, brown spots are seen. These spots are not only present on the shell, but also in the underlying flesh. At these locations, the pulp is also brown and somewhat corky and tastes slightly bitter. The symptoms of bitter pit sometimes occur until some time after the harvest or aggravated by storage and are therefore often late, usually only when the apples are brought for consumption from the warehouse, discovered. The apples but you can still eat without hesitation or for example to process applesauce.

Cause

Cause of bitter pit is a calcium deficiency in the fruit. Often, however, enough calcium in the soil. As the tree is used as the calcium due to a too high nitrogen range for the growth of wood instead of fruit growth. Also a too heavy pruning can stimulate the tree to strong growth of wood, making the calcium will not be used for fruit. An oversupply of potassium and magnesium in the soil calcium is also not taken in sufficient quantities.

Susceptibility

Particularly vulnerable are large-fruited varieties of apples, such as Jonagold or Boskoop.

Countermeasures

By pruning, which counteracts both excessive shoot growth and excessive fruit load, this can reduce the risk of bitter pit. A further option is administration of foliar fertilizers, for example, calcium nitrate or calcium chloride.