Excessive K can lead to Mg deficiency. Low Mg levels, particularly in vineyards and apple orchards are becoming more common. Zn, Mn and B deficiencies have been found in Ontario orchards. All of these disorders can be most readily identified by leaf analysis. Leaf analyses does not provide a good indication of the Ca status of the fruit.
Fruit analyses is a much better indicator.
Research has established levels of Ca in various apple cultivars needed to avoid Ca related fruit disorders. Fruit analyses may be used to indicate the long-term storageability of apples. Bunch stem breakdown of certain grape cultivars and gummosis of Italian prune plum have also been related to low levels of Ca in the fruit and avoided by foliar application of Ca. Fruit analyses may be used in Ontario to manage some of these problems. This information is provided as a public service, but we cannot guarantee that the information is current or accurate.