It is important that potassium concentrations are in balance with other cations, particularly calcium, as preferential uptake of potassium over calcium will significantly increase the risk of rotten fruit and physiological disorders.
How to minimise apple rots and storage diseases
Many disease-causing pathogens attack apple trees often leading to rotten fruit and storage rots. A balanced crop nutrition programme leads to a more robust, healthier tree more able to resist infection.
Diseases may damage the fruit directly, making it unattractive or inedible, but also weaken the apple tree by injuring or invading the leaves, trunk and branches. Damage to apple trees reduces productivity and increases susceptibility to winter injury or attack by additional pests. The most common diseases are rust, scab, different rots and fire blight.
Calcium helps prevent storage rots
Calcium increases cell wall strength making fruit and other tissues better able to withstand disease attacks. Storage rots including Gloeosporium rot and penicillium can be minimized by use of calcium. Repeated foliar applications are the most effective at alleviating this kind of damage.
Potassium excess interferes with calcium uptake
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