KIWI – Actinidia chinensis

China is the country of origin of Actinidia chinensis, a fruit that can be found in prairies and forests. It is also widespread in tropical and semi-tropical regions and in temperate regions.

The plant moved first to New Zealand and South Africa, where it was widely cultivated across the countries.

In China, Actinidia chinensis is known by the name Yang Tao. It was called Kiwi by a company based in New Zealand that exports this fruit. In fact, Kiwi is a type of bird and the symbol of New Zealand.

Not all environmental conditions are convenient for the cultivation and successful growth of kiwi. In fact, it must be cultivated in areas characterized by hot, humid summers and warm winters, starting from coastal regions, up to an altitude of 2,000 meters.

Kiwi can adapt to low temperatures during winter that drop down to -15⁰C for a relatively short period of time. However, if the temperature drops in March, it can cause significant damage to new generations and flowers. Early frosts in autumn can also widely affect the plants, especially fruits that take time to ripen.

In regions that are exposed to active winds, building windbreaks prior to cultivation is highly recommended, as the winds could break young branches, lead to dry leaves and cause their loss, as well as interrupt pollination during blooming seasons.

Kiwi is a photophilic plant, yet intense sunlight could burn the leaves and fruits. Therefore, humidity during winter must not drop below 60%, and the ideal temperature for its growth is 15⁰C.

Cultivation of this fruit can only be successful using a deep, rich and well-drained soil that contains high levels of organic matter.

As for levels of lime in the soil, they should minimal, not exceeding 5%.

Excess lime in the soil could cause pale leaves, as the plant would be unable to absorb the right amount of iron, and those symptoms could get worse in case the pH of the soil exceeds 7.5.

A well-aerated soil is a key element for the success of Kiwi cultivation. Supplemental irrigation of trees during the season remains necessary, while making sure not to add too much moisture to the soil, as it could slow the growth of trees and lower the rate of vitamin C.

Maintaining sufficient levels of moisture in the soil, especially during summer from June to September, is a key element to a successful Kiwi cultivation. As for irrigation, it should be identified according to the nature of the soil and the prevailing climate, mainly the temperature, winds, and other factors that dictate the timeframe and required levels of irrigation.

Irrigation must be interrupted 2 weeks prior to harvest, allowing the fruit to ripen well, the plant to grow and the branches to become rigid in order to resist cold winters.

Kiwi can be affected by a number of diseases that could damage the roots, plant, flowers and fruits.

The most serious disease affecting this plant is Armillaria root rot, one that could could kill the plant entirely, and prevent farmers from cultivating in the affected soil unless it is sterilized, which can be hard to do.

Fungal pathogens could cause the loss of leaves and some braches to wither. They could be prevented by taking some measures, including removing the affected parts of the plant, destroying them away from the field and implementing the appropriate pest control.

The plant flowers are also exposed to a bacteria known as Pseudomonas viridiflava, which prevents them from maturing. Symptoms of Pseudomonas viridiflava appear as yellow spots on the flowers, and the only way to address them is through some preventive measures, such as sterilizing pruning shears before and after pruning. Removing and burning pruning residues, as well spraying grass and pests could cause the transmission of this bacteria to the trees.

Eng. Ibrahim Younes