Calcium
Calcium is a vital component in cell walls and is involved in the movement of sugars and starches within the plant.
Identification
- Calcium deficiency does not usually cause foliar symptoms but does show as fruit disorders,
- Bitter pit of certain apple varieties and breakdown of Spartan apples have been related to a lack of calcium,
- A shortage of calcium in the developing fruit causes these disorders,
- There may be ample in the soil and leaves but it does not move to the expanding fruit since calcium is immobile in the plant
Bitter pit:
- The physiological breakdown of cells under the skin, causing slight depressions generally concentrated at the calyx end of the fruit,
- The tissue in these depressed areas is darkened, dry and spongy with a bitter taste,
- In some instances the symptoms may not be apparent on the fruit surface but appear under the skin,
- Large fruit from trees with light crops are more likely to have bitter pit.
- Spy is frequently affected by this disorder,
- With the right conditions, bitter pit can occur on Delicious, Idared, Crispin, Cortland, Empire, Honeycrisp and other varieties,
- The bitter pit sensitivity of some of the newer cultivars is not accurately known at this time,
- Bitter pit may not be evident at harvest but develops in stored fruit and can result in extensive loss from storage.