Citrus nutrition advice

Crop load determines fruit yield and size and a too high fruit number can result in small fruit. The use of careful thinning and growth regulators can reduce the number of fruit to an optimum amount per tree.

Crop load determines fruit yield and size and a too high fruit number can result in small fruit. The use of careful thinning and growth regulators can reduce the number of fruit to an optimum amount per tree.

Trials have shown that balanced nutrition with N, P, K, and the micronutrients, boron, iron, manganese and zinc, will help to improve citrus yield through increasing fruit weight. It is important to make sure that these nutrients are not limited during...

Citrus fruit number needs to be carefully managed and a strong supply of virtually all major and micronutrients is critical to fruit set and fruit number. Application of fertiliser prior to flowering and then through to fruit set and early fruit fill is...

Peel thickness requirements vary depending on the citrus type and market needs. Thicker peels provide higher levels of oil extraction and offer a greater resistance against pests and better shelf life. In the fresh fruit market a thicker peel is regarded...

Peel splitting is often caused by extreme fluctuations in soil moisture as well as temperature and humidity.

Creasing - the occurrence of narrow sunken furrows on the rind surface which makes processing more difficult as the peel disintegrates and is difficult to separate from the pulp and juice. Plugging - the removal of the peel in the stem end area of the...

Good crop nutrition, particularly with calcium and potassium, will maintain the integrity of the peel, helping to reduce the incidences of blemishes.

The albedo or mesocarp is the white spongy material located between the fruit segments and the outer leathery peel or flavedo. Albedo breakdown is the loss of cohesion in the cells if this white layer under the skin and any stress imposed on this as a...

The TSS content of the fruit is usually obtained from assessing the 0Brix of the fruit. The TSS or sugar content measures and includes the carbohydrates, organic acids, proteins, fats and minerals of the fruit. It represents from 10-20% of the fruit's...

During the ripening process fruit acids are degraded, the sugar content increases and the sugar/acid ratio reaches a higher value. A high level of acidity - common in under-ripe fruit - makes the fruit taste sour. Conversely, over-ripe fruits have very...

Vitamin C helps the body maintain healthy tissues and strong immune system and a cup of orange juice can contain almost 100mg of the vitamin. Good crop nutrition with balanced supplies of potassium, boron, copper, iron, manganese, molybdenum and zinc...

The TSS/Acid ratio is a key characteristic determining the taste, texture and feel of fruit segments. It is the sugar/acid ratio which contributes towards giving many fruits their characteristic flavor. It is also an indicator of commercial and sensory...

Juice content is particularly important in processed oranges but also in fresh fruit. A crop nutrition program - backed by good irrigation and water supply to help stimulate nutrient uptake during fruit production and improve the juice content is...

Citrus blight disease results in the wilt and decline of trees in groves. The cause of the disease has not been determined yet. There is no known cure for citrus blight and once trees begin to decline, they never recover. Severe pruning of blighted trees...

Root rot, due to Phytophthora spp., can be controlled by systemic fungicide use. However, good crop nutrition that helps maintain root health and productivity will also help restrict the disease's development.

HLB, also known as citrus greening disease, is fatal for citrus trees. Once a tree becomes infected, there is no cure and it will die. Spread by an insect called the Asian citrus psyllid, the disease, first found in Southern California in 2012, destroys...

Any unnatural coloration of citrus leaves needs to be investigated. A darker greening, while uncommon, could be a result of a nutrient deficiency. While rarely seen, copper deficiency leaves are dark green and enlarged. Stems are also more slender than...

Loss of leaf is a significant issue for citrus, slowing the growth of the tree and reducing fruit fill. Immediate action is needed to redress leaf drop. This includes checking for nutrient imbalances and revising fertilizer programs.

Leaf curl on citrus trees is usually associated with insect infection in particular aphid infestations on young leaves. This curled appearance remains after the aphids have gone. Leaf miner damage also causes leaf curl.

Any type of leaf yellowing in citrus needs investigation. Loss of green color indicates poor growth and tree productivity will suffer as a result. Symptoms of iron chlorosis, or yellowing in citrus, appear first on young shoots. Under severe deficiency,...

As with leaf yellowing, any blotching or other irregularity in citrus leaf color needs to be checked. Pay particular attention to where the blotching occurs; note the symptoms and if in any doubt have tissues analysed.

While most citrus trees will shed and lose leaves, any bronzing should be checked. Leaf bronzing is a typical symptom of phosphorus deficiency. Leaves are smaller than normal and older leaves die at the tips and margins. As the deficiency progresses,...

Citrus trees that lack apical dominance tend to grow in a more chaotic and less controlled way. Where citrus trees lose their apical dominance and send out multiple shoots, check for boron deficiency.

As citrus trees mature the upper foliage shades out the lower leaves, defoliation can occur and branches and twigs may die. The development of a certain amount of such wood is natural but excessive limb death, particularly in the tree interior and base...

Gum formation in the pockets on the trunk or branches of citrus trees is typically due to a Phytophthora spp. The wood beneath the blister shows a pink-orange color and it can be exacerbated by freeze damage, high water tables and salt accumulation....

Browse the complete list of all citrus articles to learn how crop nutrition affects citrus yield, quality, health and more.